Učinci hidroksipropil metilceluloze (HPMC)

Poboljšanje svojstava obrade smrznutog tijesta ima određeni praktični značaj za realizaciju velike proizvodnje visokokvalitetnog povoljnog parnog kruha. In this study, a new type of hydrophilic colloid (hydroxypropyl methylcellulose, Yang, MC) was applied to frozen dough. Učinci 0,5%, 1%, 2%) na svojstva prerade smrznutog tijesta i kvalitetu parnog kruha procijenjeni su kako bi se procijenila učinak poboljšanja HPMC -a. Utjecaj na strukturu i svojstva komponenti (pšenični gluten, pšenični škrob i kvas).
Eksperimentalni rezultati farinalnosti i istezanja pokazali su da je dodavanje HPMC -a poboljšalo svojstva obrade tijesta, a rezultati skeniranja dinamičke frekvencije pokazali su da je viskoelastičnost tijesta dodana HPMC -om tijekom razdoblja zamrzavanja, a struktura mreže tijesta ostala je relativno stabilna. In addition, compared with the control group, the specific volume and elasticity of the steamed bread were improved, and the hardness was reduced after the frozen dough added with 2% HPMC was frozen for 60 days.
Gluten od pšenice materijalna je osnova za stvaranje strukture mreže tijesta. Experiments found that the addition of I--IPMC reduced the breakage of Yd and disulfide bonds between wheat gluten proteins during frozen storage. Osim toga, rezultati nuklearne magnetske rezonancije niskog polja i diferencijalnog skeniranja pojava prijelaza i rekristalizacije vodenog stanja su ograničeni, a sadržaj zamrzavajuće vode u tijestu je smanjen, što suzbija učinak rasta kristala ledenog kristala na mikrostrukturu glutena i njezina prostorna konformacija. Scanning electron microscope showed intuitively that the addition of HPMC could maintain the stability of gluten network structure.
Škrob je najzastupljenija suha tvar u tijestu, a promjene u njegovoj strukturi izravno će utjecati na karakteristike želatine i kvalitetu konačnog proizvoda. X. Rezultati rendgenske difrakcije i DSC pokazali su da se relativna kristalnost škroba povećavala i da se entalpija želatinizacije povećala nakon zamrznutog skladištenja. S produljenjem vremena zamrznutog skladištenja, moć oteklina škroba bez dodavanja HPMC -a postupno se smanjivala, dok su karakteristike želatinizacije škroba (vršna viskoznost, minimalna viskoznost, konačna viskoznost, vrijednost propadanja i vrijednost retrogradnog) značajno povećane; Tijekom vremena skladištenja, u usporedbi s kontrolnom skupinom, s povećanjem HPMC dodavanja, promjene kristalne strukture škroba i svojstva želatinizacije postupno su se smanjivale.
Aktivnost proizvodnje fermentacije plina kvasca ima važan utjecaj na kvalitetu fermentiranih proizvoda od brašna. Kroz eksperimente utvrđeno je da bi, u usporedbi s kontrolnom skupinom, dodavanje HPMC -a moglo bolje održavati fermentacijsku aktivnost kvasca i smanjiti brzinu povećanja izvanstaničnog smanjenog sadržaja glutationa nakon 60 dana zamrzavanja, a unutar određenog raspona, zaštitni učinak HPMC -a bio je pozitivno povezan s njegovom dodatnom količinom.

Key words: steamed bread; frozen dough; hidroksipropil metilceluloza; wheat gluten; pšenični škrob; kvasac.
Sadržaj



1.1.2 Research status of steamed buns……………………………………………… ． ． ………… 1
1.1.3 Uvod smrznutog tijesta ........................................................................... 2

1.1.5 Research status of frozen dough……………………………………. ....................................... 4
1.1.6 Primjena hidrokoloida u poboljšanju kvalitete zamrznutog tijesta ……………… .5
1.1.7 Hydroxypropyl methyl cellulose (Hydroxypropyl methyl cellulose, I-IPMC) ………. 5
112 Svrha i značaj studije ............................................................ 6 6
1.3 Glavni sadržaj studije ........................................................................... 7

2.1 Uvod ................................................................................................... 8
2.2 Eksperimentalni materijali i metode ................................................................... 8
2.2.1 Eksperimentalni materijali ................................................................................... 8


2.3 Eksperimentalni rezultati i rasprava …………………………………………………………． 11
2.3.1 Indeks osnovnih komponenti pšeničnog brašna ……………………………………………… .1L

2.3.3 Učinak dodavanja HPMC -a na zatezna svojstva tijesta ……………………… 12



2.4 Sažetak poglavlja ........................................................................................... 21

3.1 Uvod ................................................................................................... 24
3.2.1 Eksperimentalni materijali ............................................................................... 25

3.2.3 Eksperimentalni reagensi ………………………………………………………………. ………………25
3.2.4 Eksperimentalne metode ...................................................................................... 25


3.3.2 The effect of adding amount of HPMC and freezing storage time on the freezable moisture content (CFW) and thermal stability……………………………………………………………………. 30
3.3.3 Effects of HPMC addition amount and freezing storage time on free sulfhydryl content (C vessel) …………………………………………………………………………………………………………. ． 34

3.3.5 Učinci količine dodavanja HPMC -a i vrijeme zamrzavanja na sekundarnu strukturu glutena ………………………………………………………………………………………………………….


3.4 Sažetak poglavlja ........................................................................................................... 43

4.1 Introduction .............................................................................................................................. ． 44
4.2 Eksperimentalni materijali i metode ............................................................． 45
4.2.1 Eksperimentalni materijali ........................................................................ ………… .45
4.2.2 Eksperimentalni aparat ............................................................................... 45

4.3 Analiza i rasprava ..............................................................................................． 48
4.3.1 Sadržaj osnovnih komponenti pšeničnog škroba ……………………………………………. 48

4.3.3 Effects of HPMC addition and freezing storage time on the shear viscosity of starch paste………………………………………………………………………………………………………………………………………. 52
4.3.4 Učinci količine dodavanja HPMC -a i smrznuto vrijeme skladištenja na dinamičku viskoelastičnost paste od škroba ……………………………………………………………………………………….

4.3.6 Effects of I-IPMC addition amount and frozen storage time on the thermodynamic properties of starch ………………………………………………………………………………………………………. ． 57


Poglavlje 5 Učinci dodavanja HPMC -a na stopu preživljavanja kvasca i aktivnost fermentacije u zamrznutim uvjetima skladištenja …………………………………………………………………………………. ． 62
5.1Introduction ...................................................................................................................................． 62
5.2 Materijali i metode ................................................................................... 62

5.2.2 Experimental methods . . . ． ． ……………………………………………………………. 63
5.3 Rezultati i rasprava ................................................................................................ 64
5.3.1 Učinak dodavanja HPMC -a i vrijeme zamrzavanja na visinu dokaza tijesta …………………………………………………………………………………………………………………………………………

5.3.3 Učinak dodavanja količine HPMC -a i vremena zamrzavanja na sadržaj glutationa u tijestu …………………………………………………………………………………………………………………………… "
5.4 Sažetak poglavlja ............................................................................................... 67

6.1 Conclusion ................................................................................................................................. ． 68
6.2 Outlook .........................................................................................................................................． 68

Slika 1.1 Strukturna formula hidroksipropil metilceluloze ………………………. ． 6



Figure 2.4 The effect of HPMC addition and freezing time on the elasticity of steamed bread………………………………………………………………………………………………………………………………. ． 20
Figure 3.1 The effect of HPMC addition and freezing time on the rheological properties of wet gluten…………………………………………………………………………………………………………………………. 30
Figure 3.2 Effects of HPMC addition and freezing time on the thermodynamic properties of wheat gluten………………………………………………………………………………………………………………. ． 34
Figure 3.3 Effects of HPMC addition and freezing time on free sulfhydryl content of wheat gluten……………………………………………………………………………………………………………………………... ． 35



Figure 3.7 The effect of HPMC addition and freezing time on the microscopic gluten network structure…………………………………………………………………………………………………………... ． 43
Figure 4.1 Starch gelatinization characteristic curve ..............................................................． 51
Slika 4.2. Thiksotropija fluidne paste od škroba ............................................................................ 52
Figure 4.3 Effects of adding amount of MC and freezing time on the viscoelasticity of starch paste……………………………………………………………………………………………………………………... ． 57

Figure 4.5 Effects of HPMC addition and freezing storage time on the thermodynamic properties of starch…………………………………………………………………………………………………………. ． 59

Slika 5.1 Učinak dodavanja HPMC -a i vremena zamrzavanja na visinu dokaza tijesta ………………………………………………………………………………………………………………… ... 66
Slika 5.2 Učinak dodavanja HPMC -a i vrijeme zamrzavanja na stopu preživljavanja kvasca ………………………………………………………………………………………………………………………． 67
Figure 5.3 Microscopic observation of yeast (microscopic examination) …………………………………………………………………………………………………………………………. 68

Popis obrazaca
Tablica 2.1 Osnovni sadržaj sastojka pšeničnog brašna …………………………………………. 11
Tablica 2.2 Učinak dodavanja I-IPMC-a na faringena svojstva tijesta …………… 11
Tablica 2.3 Utjecaj I-IPMC dodavanja na svojstva zatezanja tijesta …………………………… .14


Tablica 3.1 Sadržaj osnovnih sastojaka u glutenu ……………………………………………… .25
Table 3.2 Effects of I-IPMC addition amount and freezing storage time on the phase transition enthalpy (Yi IV) and freezer water content (e chat) of wet gluten………………………. 31
Table 3.3 Effects of HPMC addition amount and freezing storage time on the peak temperature (product) of thermal denaturation of wheat gluten…………………………………………. 33
Tablica 3.4 Vrhovni položaji sekundarnih struktura proteina i njihovih zadataka ………… .37

Tablica 3.6 Učinci dodavanja I-IPMC-a i vrijeme zamrzavanja na površinsku hidrofobnost pšeničnog glutena …………………………………………………………………………………. 41
Tablica 4.1 Sadržaj osnovnih komponenti pšeničnog škroba ……………………………………… 49
Tablica 4.2 Učinci količine dodavanja HPMC -a i smrznuto vrijeme skladištenja na karakteristike želatinizacije pšeničnog škroba …………………………………………………………………………………………………………………………
Table 4.3 Effects of I-IPMC addition and freezing time on the shear viscosity of wheat starch paste…………………………………………………………………………………………………………………………. 55
Tablica 4.4 Učinci I-IPMC količine dodavanja i zamrznuto vrijeme skladištenja na termodinamička svojstva želatinizacije škroba ……………………………………………………… .60
Poglavlje 1. predgovor
1.1Resarni status u zemlji i inozemstvu
1.1.1 Uvod u parni kruh
Kruh s parom odnosi se na hranu napravljenu od tijesta nakon provjere i pare. As a traditional Chinese pasta food, steamed bread has a long history and is known as "Oriental Bread". Budući da je njegov gotov proizvod hemisferičan ili izdužen oblika, mekan u ukusu, ukusan po ukusu i bogat hranjivim tvarima [L], već je dugo bio popularan među javnošću. It is the staple food of our country, especially the northern residents. Potrošnja čini oko 2/3 prehrambene strukture proizvoda na sjeveru i oko 46% prehrambene strukture proizvoda od brašna u zemlji [21].


1)Development of new characteristic steamed buns. Through the innovation of steamed bread raw materials and the addition of functional active substances, new varieties of steamed breads have been developed, which have both nutrition and function. Uspostavio je standard za ocjenu za kvalitetu raznog zrnca na pari kruha glavnim komponentama; Fu et a1. (2015) added lemon pomace containing dietary fiber and polyphenols to steamed bread, and evaluated the antioxidant activity of steamed bread; Hao & Beta (2012) studied barley bran and flaxseed (rich in bioactive substances) The production process of steamed bread [5]; Shiau et a1. (2015) evaluated the effect of adding pineapple pulp fiber on dough rheological properties and steamed bread quality [6].
2)Research on the processing and compounding of special flour for steamed bread. The effect of flour properties on the quality of dough and steamed buns and the research on new special flour for steamed buns, and based on this, an evaluation model of flour processing suitability was established [7]; Na primjer, učinci različitih metoda mljevenja brašna na kvalitetu brašna i parenih peciva [7] 81; The effect of the compounding of several waxy wheat flours on the quality of steamed bread [9J et al.; Zhu, Huang, &Khan (2001) evaluated the effect of wheat protein on the quality of dough and northern steamed bread, and considered that gliadin/ Glutenin was significantly negatively correlated with dough properties and steamed bread quality [lo]; Zhang, et a1. (2007) analyzed the correlation between gluten protein content, protein type, dough properties and steamed bread quality, and concluded that the content of high molecular weight glutenin subunit (1ligh.molecular-weight, HMW) and total protein content are all related to the quality of northern steamed bread. imaju značajan utjecaj [11].
3) Istraživanje pripreme tijesta i tehnologiju izrade kruha. Research on the influence of steamed bread production process conditions on its quality and process optimization; Liu Changhong et al. (2009) showed that in the process of dough conditioning, process parameters such as water addition, dough mixing time, and dough pH value have an impact on the whiteness value of steamed bread. It has a significant impact on sensory evaluation. Ako uvjeti procesa nisu prikladni, uzrokovat će da proizvod postane plava, tamna ili žuta. Rezultati istraživanja pokazuju da je tijekom postupka pripreme tijesta količina dodane vode doseže 45%, a vrijeme miješanja tijesta je 5 minuta, ~ kada je pH vrijednost tijesta bila 6,5 ​​u trajanju od 10 minuta, vrijednost bjeline i senzorna procjena parenih peciva izmjerenih brojilom bjeline bili su najbolji. When rolling the dough 15-20 times at the same time, the dough is flaky, smooth, elastic and shiny surface; when the rolling ratio is 3:1, the dough sheet is shiny, and the whiteness of the steamed bread increases [l to; Li, et a1. (2015) explored the production process of compound fermented dough and its application in steamed bread processing [13].
4) Istraživanje poboljšanja kvalitete kruha s parom. Istraživanje dodavanja i primjene poboljšanih kvaliteta kruha; Uglavnom, uključujući aditive (poput enzima, emulgatora, antioksidanata itd.) I ostalih egzogenih proteina [14], škroba i modificiranog škroba [15], itd. Dodavanje i optimizacija odgovarajućeg procesa, posebno je primjećena da su se u posljednjih godina bili u kompletima koji su bili razvijeni i proizvodi. patients with Coeliac Disease [16.1 cit.
5)Preservation and anti-aging of steamed bread and related mechanisms. Pan Lijun i sur. (2010) optimizirao je kompozitni modifikator s dobrim efektom protiv starenja eksperimentalnim dizajnom [l ne; Wang, et a1. (2015) studied the effects of gluten protein polymerization degree, moisture, and starch recrystallization on the increase of steamed bread hardness by analyzing the physical and chemical properties of steamed bread. Rezultati su pokazali da su gubitak vode i rekristalizacija škroba glavni razlozi starenja parnog kruha [20].
6)Research on the application of new fermented bacteria and sourdough. Jiang, et a1. (2010) Application of Chaetomium sp. fermented to produce xylanase (with thermostable) in steamed bread [2l'; Gerez, et a1. (2012) koristili su dvije vrste bakterija mliječne kiseline u fermentiranim proizvodima brašna i procijenili njihovu kvalitetu [221; Wu i sur. (2012) studied the influence of sourdough fermented by four kinds of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus, sanfranciscemis , Lactobacillus brevis and Lactobacillus delbrueckii subsp bulgaricus) on the quality (specific volume, texture, fermentation flavor, etc.) of northern steamed bread [23]; i Gerez, et A1. (2012) used the fermentation characteristics of two kinds of lactic acid bacteria to accelerate the hydrolysis of gliadin to reduce the allergenicity of flour products [24] and other aspects.
7) Istraživanje o primjeni smrznutog tijesta u pari kruha.
Među njima je parni kruh sklon starenju u konvencionalnim uvjetima skladištenja, što je važan faktor koji ograničava razvoj proizvodnje parnog kruha i preradu industrijalizacije. After aging, the quality of steamed bread is reduced - the texture becomes dry and hard, dregs, shrinks and cracks, the sensory quality and flavor deteriorate, the digestion and absorption rate decreases, and the nutritional value decreases. This not only affects its shelf life, but also creates a lot of waste. Prema statistikama, godišnji gubitak uslijed starenja je 3% proizvodnje proizvoda od brašna. 7%. With the improvement of people's living standards and health awareness, as well as the rapid development of the food industry, how to industrialize the traditional popular staple noodle products including steamed bread, and obtain products with high quality, long shelf life and easy preservation to meet the needs of the growing demand for fresh, safe, high-quality and convenient food is a long-standing technical problem. Based on this background, frozen dough came into being, and its development is still in the ascendant.
1.1.3 Uvođenje za smrznuto tijesto
Smrznuto tijesto nova je tehnologija za preradu i proizvodnju proizvoda od brašna razvijenih 1950 -ih. Uglavnom se odnosi na uporabu pšeničnog brašna kao glavne sirovine i vode ili šećera kao glavnih pomoćnih materijala. Baked, packed or unpacked, quick-freezing and other processes make the product reach a frozen state, and in. For products frozen at 18"C, the final product needs to be thawed, proofed, cooked, etc. [251].






Kolači i drugi proizvodi od tjestenine imaju različite stupnjeve primjene [26-27]. Prema nepotpunim statistikama, do 1990. godine 80% pekara u Sjedinjenim Državama koristilo je smrznuto tijesto; 50% of bakeries in Japan also used frozen dough. twentieth century


The frozen dough technology undoubtedly provides a feasible idea for the industrialized production of traditional Chinese food such as steamed bread. However, this processing technology still has some shortcomings, especially under the condition of longer freezing time, the final product will have longer proofing time, lower specific volume, higher hardness, Water loss, poor taste, reduced flavor, and quality deterioration. Osim toga, zbog zamrzavanja
Tijesto je višekomponentna (vlaga, protein, škrob, mikroorganizam itd.), Višefazna (kruta, tekuća, plin), multi-skala (makromolekula, male molekule), multi-infer sučelje (sučelje čvrstog plina), sučelje, tako i sučelja, pakiranog meka).
Most studies have found that the formation and growth of ice crystals in frozen foods is an important factor leading to the deterioration of product quality [291]. Ice crystals not only reduce the survival rate of yeast, but also weaken the gluten strength, affect the starch crystallinity and gel structure, and damage the yeast cells and release the reducing glutathione, which further reduces the gas holding capacity of gluten. In addition, in the case of frozen storage, temperature fluctuations can cause ice crystals to grow due to recrystallization [30]. Stoga je kako kontrolirati štetne učinke stvaranja i rasta kristala ledenog kristala na škrobu, glutenu i kvascima ključ je za rješavanje gornjih problema, a to je i vruće istraživačko polje i smjer. In the past ten years, many researchers have been engaged in this work and achieved some fruitful research results. However, there are still some gaps and some unresolved and controversial issues in this field, which need to be further explored, such as:

b) Budući da postoje određene razlike u tehnologiji obrade i proizvodnje i formuli različitih proizvoda od brašna, još uvijek nedostaje istraživanja o razvoju odgovarajućeg posebnog smrznutog tijesta u kombinaciji s različitim tipovima proizvoda;


1.1.5Research Status smrznutog tijesta
S obzirom na gore navedene probleme i izazove smrznutog tijesta, dugoročno inovativno istraživanje primjene tehnologije smrznutog tijesta, kontrolu kvalitete i poboljšanje proizvoda zamrznutih tijesta i povezani mehanizam promjena u strukturi i svojstava materijalnih komponenti u sustavu zamrznutog tijesta i propuštanja kvalitete u polja u polja Frotzen Duugh. Konkretno, glavna domaća i strana istraživanja posljednjih godina uglavnom se usredotočuju na sljedeće točke:
I. Utvrdite promjene u strukturi i svojstvima smrznutog tijesta produljenjem vremena skladištenja zamrzavanja, kako bi se istražili razlozi pogoršanja kvalitete proizvoda, posebno utjecaja kristalizacije leda na biološke makromolekule (protein, škrob itd.), Na primjer, kristalizaciju leda. Formiranje i rast i njezin odnos s vodenim stanjem i distribucijom; changes in wheat gluten protein structure, conformation and properties [31]; changes in starch structure and properties; changes in dough microstructure and related properties, etc. 361.

Ii. Optimization of frozen dough production process, frozen storage conditions and formula. During the production of frozen dough, temperature control, proofing conditions, pre-freezing treatment, freezing rate, freezing conditions, moisture content, gluten protein content, and thawing methods will all affect the processing properties of frozen dough [37]. Općenito, veće stope zamrzavanja proizvode kristale leda koji su manji i ravnomjernije raspoređeni, dok niže stope zamrzavanja proizvode veće kristale leda koji nisu ravnomjerno raspoređeni. In addition, a lower freezing temperature even below the glass transition temperature (CTA) can effectively maintain its quality, but the cost is higher, and the actual production and cold chain transportation temperatures are usually small. In addition, the fluctuation of the freezing temperature will cause recrystallization, which will affect the quality of the dough.
Iii. Using additives to improve the product quality of frozen dough. Kako bi poboljšali kvalitetu proizvoda smrznutog tijesta, mnogi su istraživači napravili istraživanja iz različitih perspektiva, na primjer, poboljšavajući toleranciju na niske temperature materijalnih komponenti u smrznutom tijestu, koristeći aditive za održavanje stabilnosti strukture mreže tijesta [45.56], itd. Upotreba aditiva je učinkovita i često korištena metoda. Uglavnom uključuju, i) pripravke od enzima, poput, transglutaminaza, o [. Amilaza; ii) emulgatori, kao što su monogliceridni stearat, Datem, SSL, CSL, Datem itd.; iii) antioxidants, ascorbic acid, etc.; iv) polysaccharide hydrocolloids, such as guar gum, yellow Originalgum, gum Arabic, konjac gum, sodium alginate, etc.; v) other functional substances, such as Xu, et a1. (2009) added Ice-structuring Proteins to wet gluten mass under freezing conditions, and studied its protective effect and mechanism on the structure and function of gluten protein [y71.
Ⅳ. Uzgoj kvasca antifriza i primjena novog antifriza kvasca [58-59]. Sasano, et a1. (2013) obtained freeze-tolerant yeast strains through hybridization and recombination between different strains [60-61], and S11i, Yu, & Lee (2013) studied a biogenic ice nucleating agent derived from Erwinia Herbicans used to protect the fermentation viability of yeast under freezing conditions [62J.
1.1.6Aplikacija hidrokoloida u poboljšanju kvalitete zamrznutog tijesta
Kemijska priroda hidrokoloida je polisaharid, koji se sastoji od monosaharida (glukoza, ramnoza, arabinoza, manoza itd.) Do 0 [. 1-4. Glycosidic bond or/and a. 1-"6. Glikozidna veza ili B. 1-4. Glikozidna veza i 0 [.1-3. Visoki molekularni organski spoj formiran kondenzacijom glikozidne veze ima bogatu sortu i može se otprilike podijeliti u: ① Derivati ​​pol-celuloze (MC) (MC), karboksim-celuloza, karboksim-celuloza (MC) konjac gum, guar gum, gum Arabic ; ③ seaweed polysaccharides, such as seaweed gum, carrageenan; ④ microbial polysaccharides, such as Xanthan gum .Polysaccharide has strong hydrophilicity because it contains a large number of hydroxyl groups that are easy to form hydrogen bonds with water, and has the functions of controlling the migration, state and distribution of water in the food system. Therefore, the addition of hydrophilic colloids gives food Many functions, properties, and qualities of hydrocolloids are closely related to the interaction between polysaccharides and water and other macromolecular substances. At the same time, due to the multiple functions of thickening, stabilizing, and water retention, hydrocolloids are widely used to include in the food processing of flour products. Wang Xin et al. (2007) studied the effect of adding seaweed polysaccharides and gelatin on the glass transition temperature of dough [631. Wang Yusheng et al. (2013) believed that compound addition of a variety of hydrophilic colloids can significantly change the flow of dough. Change the properties, improve the tensile strength of the dough, enhance the elasticity of the dough, but reduce the extensibility of the dough [delete.
1.1.7hidroksipropil metil celuloza (hidroksipropil metil celuloza, I-IPMC)

Due to the existence of hydrogen bonds in the linear molecular chain and crystalline structure, cellulose has poor water solubility, which also limits its application range. However, the presence of substituents on the side chain of HPMC breaks the intramolecular hydrogen bonds, making it more hydrophilic [66l], which can quickly swell in water and form a stable thick colloidal dispersion at low temperatures Tie. As a cellulose derivative-based hydrophilic colloid, HPMC has been widely used in the fields of materials, papermaking, textiles, cosmetics, pharmaceuticals and food [6 71]. Konkretno, zbog svojih jedinstvenih reverzibilnih svojstava termo-geliranja, HPMC se često koristi kao komponenta kapsule za lijekove za kontrolirano oslobađanje; U hrani se HPMC koristi i kao površinski aktivni tlak, zgušnjavanje, emulgatori, stabilizatori itd. I igraju ulogu u poboljšanju kvalitete srodnih proizvoda i ostvarivanju određenih funkcija. Na primjer, dodavanje HPMC -a može promijeniti karakteristike želatinizacije škroba i smanjiti snagu gela paste od škroba. , HPMC može smanjiti gubitak vlage u hrani, smanjiti tvrdoću jezgre kruha i učinkovito inhibirati starenje kruha.
Iako se HPMC u određenoj mjeri koristi u tjestenini, on se uglavnom koristi kao sredstvo protiv starenja i sredstvo za zadržavanje vode za kruh itd., Koji mogu poboljšati volumen, svojstva teksture i rok trajanja roka [71.74]. Međutim, u usporedbi s hidrofilnim koloidima kao što su guar guma, ksantanska guma i alginat natrija [75-771], nema mnogo studija o primjeni HPMC-a u smrznutom tijestu, može li poboljšati kvalitetu parnog kruha prerađenog iz smrznutog tijesta. There is still a lack of relevant reports on its effect.

1.2Reastragentna svrha i značaj
Trenutno je aplikacija i velika proizvodnja tehnologije zamrznutog tijesta u mojoj zemlji u cjelini još uvijek u fazi razvoja. Istodobno, postoje određene zamke i nedostaci u samom smrznutom tijestu. These comprehensive factors undoubtedly restrict the further application and promotion of frozen dough. on the other hand,this also means that the application of frozen dough has great potential and broad prospects, especially from the perspective of combining frozen dough technology with the industrialized production of traditional Chinese noodles (non-)fermented staple food, to develop more products that meet the needs of Chinese residents. It is of practical significance to improve the quality of the frozen dough based on the characteristics of Chinese pastry and the dietary habits, and is suitable for the processing characteristics of Chinese pastry.

1.3 Glavni sadržaj studije
Općenito se vjeruje da je tijesto tipičan složeni sustav meke tvari s karakteristikama multikomponentnih, višefaznih, višefaznih i više faza.
Učinci dodavanja količine i smrznuto vrijeme skladištenja na strukturu i svojstva smrznutog tijesta, kvalitetu proizvoda smrznutog tijesta (parni kruh), struktura i svojstva pšeničnog glutena, strukture i svojstava pšeničnog škroba i fermentacijske aktivnosti kvasca. Based on the above considerations, the following experimental design was made in this research topic:
1)Select a new type of hydrophilic colloid, hydroxypropyl methylcellulose (HPMC) as an additive, and study the addition amount of HPMC under different freezing time (0, 15, 30, 60 days; the same below) conditions. (0%, 0,5%, 1%, 2%; isto u nastavku) o reološkim svojstvima i mikrostrukturi smrznutog tijesta, kao i o kvaliteti proizvoda od tijesta - parenim kruhom (uključujući specifični volumen parnog kruha), tekstura), istražite učinak dodavanja HPMC -a i na evaluaciju na paru na prepuštenu svojstvo na obradu obrade obrada svojstava smrznutog tijesta;

3) Iz perspektive mehanizma poboljšanja, učinci različitih dodataka HPMC -a na svojstva želatine, svojstva gela, svojstva kristalizacije i termodinamička svojstva škroba u različitim uvjetima vremena skladištenja zamrzavanja.

Poglavlje 2 Učinci dodavanja I-IPMC-a na svojstva prerade smrznutog tijesta i kvalitetu parenog kruha

Generally speaking, the material composition of dough used for making fermented flour products mainly includes biological macromolecular substances (starch, protein), inorganic water, and yeast of organisms, and is formed after hydration, cross-linking and interaction. Razvijen je stabilan i složen materijalni sustav s posebnom strukturom. Numerous studies have shown that the properties of the dough have a significant impact on the quality of the final product. Therefore, by optimizing the compounding to meet the specific product and it is a research direction to improve the dough formulation and technology of the quality of the product or food for use; on the other hand, improving or improving the properties of dough processing and preservation to ensure or improve the quality of the product is also an important research issue.
Kao što je spomenuto u uvodu, dodavanje HPMC -a u sustav tijesta i ispitivanje njegovih učinaka na svojstva tijesta (Farin, izduženje, reologija itd.) I konačna kvaliteta proizvoda dvije su usko povezane studije.


2.2.1 Eksperimentalni materijali
Zhongyu Wheat Flour Binzhou Zhongyu Food Co., Ltd.; Angel Active Dry Kvasac Angel Quast Co., Ltd.; HPMC (stupanj supstitucije metil od 28%.30%, hidroksipropilni supstitucija stupanj od 7%.12%) Aladdin (Šangaj) Tvrtka kemijskog reagensa; all chemical reagents used in this experiment are of analytical grade;


Bps. 500Cl okvir stalne temperature i vlage



Sm. 986S mikser tijesta
C21. KT2134 Kuhač za indukciju
Powder meter. E
Extensometer. E
Otkrivanje R3 rotacijski reometar

Fd. 1b. 50 sušilica za zamrzavanje vakuuma


Proizvođač


Sartorius, Njemačka

Top Kitchen Appliance Technology Co., Ltd.
Guangdong Midea Life Appliance Manufacturing Co., Ltd.




Beijing Bo Yi Kang Experimental Instrument Co., Ltd.
Huang Shi Heng Feng Medical Equipment Co., Ltd.
Danska Foss Company
2.2.3 Eksperimentalna metoda
2.2.3.1 Određivanje osnovnih komponenti brašna




Određivanje vlačnih svojstava tijesta prema GB/T 14615.2006 [831.
2.2.3.4 Proizvodnja smrznutog tijesta
Pogledajte postupak izrade tijesta GB/T 17320.1998 [84]. Weigh 450 g of flour and 5 g of active dry yeast into the bowl of the dough mixer, stir at low speed to fully mix the two, and then add 245 mL of low-temperature (Distilled water (pre-stored in the refrigerator at 4°C for 24 hours to inhibit the activity of yeast), first stir at low speed for 1 min, then at medium speed for 4 min until dough is formed. Take out the dough and divide it into about 180g / Porcija, grickajte ga u cilindrični oblik, zatim ga zapečaćuju vrećicom za zatvarač i stavite ga. Zamrzavanje na 18 ° C 15, 30 i 60 dana. group.
2.2.3.5 Određivanje reoloških svojstava tijesta

A sample (about 2 g) of the central part of the partially melted dough was cut and placed on the bottom plate of the rheometer (Discovery R3). Prvo, uzorak je podvrgnut dinamičnom skeniranju naprezanja. Specifični eksperimentalni parametri postavljeni su na sljedeći način: korištena je paralelna ploča s promjerom od 40 mm, jaz je postavljen na 1000 mln, temperatura je bila 25 ° C, a raspon skeniranja 0,01%. 100%, the sample rest time is 10 min, and the frequency is set to 1Hz. The Linear Viscoelasticity Region (LVR) of the tested samples was determined by strain scanning. Then, the sample was subjected to a dynamic frequency sweep, and the specific parameters were set as follows: the strain value was 0.5% (in the LVR range), the resting time, the fixture used, the spacing, and the temperature were all consistent with the strain sweep parameter settings. Five data points (plots) were recorded in the rheology curve for each 10-fold increase in frequency (linear mode). After each clamp depression, the excess sample was gently scraped with a blade, and a layer of paraffin oil was applied to the edge of the sample to prevent water loss during the experiment. Each sample was repeated three times.
2.2.3.6 Sadržaj vode za zamrzavanje (sadržaj zamrzavajuće vode, CF unutarnje određivanje) u tijestu

Među njima, 厶 predstavlja latentnu toplinu vlage, a njegova vrijednost je 334 j dan; MC (ukupni sadržaj vlage) predstavlja ukupni sadržaj vlage u tijestu (mjeren prema GB 50093.2010T78]). Svaki je uzorak ponovljen tri puta.

2.2.3.8 Procjena kvalitete parnog kruha

According to GB/T 20981.2007 [871, the rapeseed displacement method was used to measure the volume (work) of the steamed buns, and the mass (m) of the steamed buns was measured using an electronic balance. Svaki je uzorak ponovljen tri puta.
Specifični volumen parnog kruha (CM3 / G) = Volumen parnog kruha (CM3) / Masa kruha na pari (G)
(2) Određivanje svojstava teksture jezgre na pari kruha
Refer to the method of Sim, Noor Aziah, Cheng (2011) [88] with minor modifications. Uzorak jezgrenog kruha od 20x 20 x 20 mn'13 izrezan je iz središnjeg područja parnog kruha, a TPA (analiza profila teksture) parnog kruha izmjerena je ispitivačem fizičkog svojstva. Specific parameters: the probe is P/100, the pre-measurement rate is 1 mm/s, the mid-measurement rate is 1 mm/s, the post-measurement rate is 1 mm/s, the compression deformation variable is 50%, and the time interval between two compressions is 30 S, the trigger force is 5 g. Each sample was repeated 6 times.
2.2.3.9 Obrada podataka



Tab 2．1 Sadržaj elementarnog sastojka pšeničnog brašna

2.3.2 Učinak dodavanja I-IPMC-a na faringena svojstva tijesta

Because HPMC has strong water retention and water holding capacity, and is more absorbent than wheat starch and wheat gluten [8"01, therefore, the addition of HPMC improves the water absorption rate of the dough. The dough forming time is when the dough consistency reaches 500 The time required for FU, the addition of HPMC reduces the dough formation time, which indicates that the addition of HPMC promotes the formation of the Vrijeme stabilnosti tijesta je vrijeme kada se dosljednost tijesta održava iznad 500 FU, a HPMC povećava vrijeme stabilnosti tijesta, što je zbog tijesta uzrokovano skraćivanjem vremena formiranja i relativne stabilnosti dosljednosti tijesta, a konačna je i ranicija iznajmljivanja. HPMC može igrati ulogu u stabilizaciji dosljednosti tijesta.

NAPOMENA: Različita manja slova natpisa u istom stupcu ukazuju na značajnu razliku (P <0,05)

The tensile properties of the dough can better reflect the processing properties of the dough after proofing, including the extensibility, tensile resistance and stretch ratio of the dough. Vučna svojstva tijesta pripisuju se produžetku molekula glutenina u proširivosti tijesta, jer umrežavanje molekularnih lanca glutenina određuje elastičnost tijesta [921]. Termonia, Smith (1987) [93] vjerovao je da produženje polimera ovisi o dva kemijska kinetička procesa, odnosno razbijanju sekundarnih veza između molekularnih lanca i deformacije umreženih molekularnih lanaca. Kad je brzina deformacije molekularnog lanca relativno niska, molekularni lanac se ne može dovoljno i brzo nositi sa stresom stvorenim istezanjem molekularnog lanca, što zauzvrat dovodi do lomljenja molekularnog lanca, a duljina produženja molekulskog također je kratka. Only when the deformation rate of the molecular chain can ensure that the molecular chain can be deformed quickly and sufficiently, and the covalent bond nodes in the molecular chain will not be broken, the elongation of the polymer can be increased. Therefore, changing the deformation and elongation behavior of the gluten protein chain will have an impact on the tensile properties of the dough [92].
Table 2.3 lists the effects of different amounts of HPMC (O, 0.5%, 1% and 2%) and different proofing 1'9 (45 min, 90 min and 135 min) on the dough tensile properties (energy, stretch resistance, maximum stretch resistance, elongation, stretch ratio and maximum stretch ratio). The experimental results show that the tensile properties of all dough samples increase with the extension of the proofing time except the elongation which decreases with the extension of the proofing time. For the energy value, from 0 to 90 min, the energy value of the rest of the dough samples increased gradually except for the addition of 1% HPMC, and the energy value of all dough samples increased gradually. Nije bilo značajnih promjena. This shows that when the proofing time is 90 min, the network structure of the dough (cross-linking between molecular chains) is completely formed. Stoga se vrijeme provjeravanja dodatno proširuje i nema značajne razlike u energetskoj vrijednosti. Istovremeno, to također može pružiti referencu za određivanje vremena provjere tijesta. As the proofing time prolongs, more secondary bonds between molecular chains are formed and the molecular chains are more closely cross-linked, so the tensile resistance and the maximum tensile resistance increase gradually. At the same time, the deformation rate of molecular chains also decreased with the increase of secondary bonds between molecular chains and the tighter cross-linking of molecular chains, which led to the decrease of the elongation of the dough with the excessive extension of the proofing time. The increase in tensile resistance/maximum tensile resistance and the decrease in elongation resulted in an increase in tensile LL/maximum tensile ratio.
Međutim, dodavanje HPMC -a može učinkovito suzbiti gornji trend i promijeniti svojstva zatezanja tijesta. With the increase of HPMC addition, the tensile resistance, maximum tensile resistance and energy value of the dough all decreased correspondingly, while the elongation increased. Specifically, when the proofing time was 45 min, with the increase of HPMC addition, the dough energy value decreased significantly, from 148.20-J: 5.80 J (blank) to 129.70-J respectively: 6.65 J (add 0.5% HPMC), 120.30 ± 8.84 J (add 1% HPMC), and 110.20-a: 6.58
J (2% HPMC dodano). At the same time, the maximum tensile resistance of the dough decreased from 674.50-a: 34.58 BU (blank) to 591.80--a: 5.87 BU (adding 0.5% HPMC), 602.70± 16.40 BU (1% HPMC added), and 515.40-a: 7.78 BU (2% HPMC added). Međutim, izduživanje tijesta povećalo se sa 154,75+7,57 MITI (prazno) na 164,70-A: 2,55 m/rl (dodavanje 0,5% HPMC), 162,90-A: 4 .05 min (1% HPMC dodano), a 1 67,20-A: 1,98 min). This may be due to the increase of the plasticizer-water content by adding HPMC, which reduces the resistance to the deformation of the gluten protein molecular chain, or the interaction between HPMC and the gluten protein molecular chain changes its stretching behavior, which in turn affects It improves the tensile properties of the dough and increases the extensibility of the dough, which will affect the quality (eg, specific volume, texture) of konačni proizvod.

Slika 2．1 Utjecaj dodavanja HPMC -a na reološka svojstva smrznutog tijesta
Figure 2.1 shows the change of storage modulus (elastic modulus, G') and loss modulus (viscous modulus, G") of dough with different HPMC content from 0 days to 60 days. The results showed that with the prolongation of freezing storage time, the G' of the dough without adding HPMC decreased significantly, while the change of G" was relatively small, and the /an Q (G''/G') increased. This may be due to the fact that the network structure of the dough is damaged by ice crystals during freezing storage, which reduces its structural strength and thus the elastic modulus decreases significantly. However, with the increase of HPMC addition, the variation of G' gradually decreased. In particular, when the added amount of HPMC was 2%, the variation of G' was the smallest. To pokazuje da HPMC može učinkovito inhibirati stvaranje kristala leda i povećanje veličine kristala leda, smanjujući na taj način oštećenje strukture tijesta i održavajući strukturnu čvrstoću tijesta. In addition, the G' value of dough is greater than that of wet gluten dough, while the G" value of dough is smaller than that of wet gluten dough, mainly because the dough contains a large amount of starch, which can be adsorbed and dispersed on the gluten network structure. It increases its strength while retaining excess moisture.
2.3.5 Učinci količine dodavanja HPMC -a i vrijeme skladištenja zamrzavanja na zamrzivi sadržaj vode (OW) u smrznutom tijestu
Not all the moisture in the dough can form ice crystals at a certain low temperature, which is related to the state of the moisture (free-flowing, restricted, combined with other substances, etc.) and its environment. Voda zamrzavanja je voda u tijestu koja može proći fazu transformacije kako bi se formirale kristale leda na niskim temperaturama. The amount of freezable water directly affects the number, size and distribution of ice crystal formation. In addition, the freezable water content is also affected by environmental changes, such as the extension of freezing storage time, the fluctuation of freezing storage temperature, and the change of material system structure and properties. Za smrznuto tijesto bez dodanog HPMC -a, s produljenjem vremena zamrzavanja, Q silicij se značajno povećao, sa 32,48 ± 0,32% (smrznuto skladištenja u trajanju od 0 dana) na 39,13 ± 0,64% (zamrznuti skladištenje u trajanju od 0 dana). Tibetan for 60 days), the increase rate was 20.47%. However, after 60 days of frozen storage, with the increase of HPMC addition, the increase rate of CFW decreased, followed by 18.41%, 13.71%, and 12.48% (Table 2.4). At the same time, the o∥ of the unfrozen dough decreased correspondingly with the increase of the amount of HPMC added, from 32.48a-0.32% (without adding HPMC) to 31.73±0.20% in turn. (adding0.5% HPMC), 3 1.29+0.03% (adding 1% HPMC) and 30.44±0.03% (adding 2% HPMC) Water holding capacity, inhibits the free flow of water and reduces the amount of water that can be frozen. U procesu skladištenja zamrzavanja, zajedno s rekristalizacijom, struktura tijesta je uništena, tako da se dio nemrzabilne vode pretvara u zamrzavajuću vodu, povećavajući na taj način sadržaj vodene vode. Međutim, HPMC može učinkovito inhibirati stvaranje i rast kristala leda i zaštititi stabilnost strukture tijesta, čime se učinkovito inhibira povećanje sadržaja zamrzavanja vode. To je u skladu s promjenom zakona o zamrzavajućem sadržaju vode u smrznutom vlažnom tijestu za gluten, ali budući da tijesto sadrži više škroba, vrijednost CFW -a je manja od vrijednosti G∥ koja je određena vlažnim tijestom glutena (tablica 3.2).

Slika 2．2 Utjecaj dodavanja HPMC -a i smrznutog skladištenja na specifičnu količinu kineskog parnog kruha

Međutim, specifični volumen parnog kruha napravljenog od smrznutog tijesta smanjio se produženjem vremena zamrznutog skladištenja. Među njima je specifični volumen parnog kruha napravljenog od smrznutog tijesta bez dodavanja HPMC -a bio 2,835 ± 0,064 cm3/g (smrznuti skladištenje). 0 dana) do 1,495 ± 0,070 cm3/g (smrznuto skladištenje 60 dana); dok je specifični volumen parnog kruha napravljenog od smrznutog tijesta dodao s 2% HPMC pao sa 3,160 ± 0,041 cm3/g na 2,160 ± 0,041 cm3/g. 451 ± 0,033 cm3/g, dakle, specifični volumen parnog kruha napravljenog od smrznutog tijesta dodanog s HPMC -om smanjio se s povećanjem dodane količine. Budući da specifični volumen parnog kruha ne utječe samo na aktivnost fermentacije kvasca (fermentacijski plin), umjereni kapacitet držanja plina mrežne strukture tijesta također ima važan utjecaj na specifični volumen konačnog proizvoda [96'9 citiran. Rezultati mjerenja gore navedenih reoloških svojstava pokazuju da su integritet i strukturna čvrstoća strukture mreže tijesta uništeni tijekom postupka skladištenja zamrzavanja, a stupanj oštećenja pojačava se produljenjem vremena zamrzavanja. Tijekom postupka, njegov kapacitet držanja plina je loš, što zauzvrat dovodi do smanjenja specifičnog volumena parnog kruha. However, the addition of HPMC can more effectively protect the integrity of the dough network structure, so that the air-holding properties of the dough are better maintained, therefore, in O. During the 60-day frozen storage period, with the increase of HPMC addition, the specific volume of the corresponding steamed bread decreased gradually.
2.3.6.2 Učinci količine dodavanja HPMC -a i zamrznuto vrijeme skladištenja na svojstva teksture parnog kruha
TPA (Textural Profile Analyses) physical property test can comprehensively reflect the mechanical properties and quality of pasta food, including hardness, elasticity, cohesion, chewiness and resilience. Slika 2.3 prikazuje učinak HPMC dodavanja i vremena smrzavanja na tvrdoću parnog kruha. Rezultati pokazuju da se za svježe tijesto bez tretmana zamrzavanja, s povećanjem HPMC dodavanja, tvrdoća parnog kruha značajno raste. decreased from 355.55±24.65g (blank sample) to 310.48±20.09 g (add O.5% HPMC), 258.06±20.99 g (add 1% t-IPMC) and 215.29 + 13.37 g (2% HPMC added). This may be related to the increase in specific volume of steamed bread. Osim toga, kao što se može vidjeti na slici 2.4, kako se povećava količina dodavanja HPMC -a, proljeće parnog kruha izrađenog od svježeg tijesta značajno se povećava, od 0,968 ± 0,006 (prazno) na 1, respektivno. .020 ± 0.004 (add 0.5% HPMC), 1.073 ± 0.006 (add 1% I-IPMC) and 1.176 ± 0.003 (add 2% HPMC). The changes of the hardness and elasticity of steamed bread indicated that the addition of HPMC could improve the quality of steamed bread. To je u skladu s rezultatima istraživanja Rosell, Rojas, Benedito de Barber (2001) [95] i Barcenas, Rosell (2005) [Worms], to jest, HPMC može značajno smanjiti tvrdoću kruha i poboljšati kvalitetu kruha.

Slika 2．3 Učinak dodavanja HPMC -a i smrznuto skladištenja na tvrdoću kineskog parnog kruha

The hardness of the steamed bread made of frozen dough with 2% HPMC increased from 208.233 ± 15.566 g (frozen storage for 0 days) to 564.978 ± 82.849 g (frozen storage for 60 days). Slika 2．4 Utjecaj dodavanja HPMC -a i zamrznutog skladištenja na proljeće kineskog parnog kruha u smislu elastičnosti, elastičnost parnog kruha napravljenog od smrznutog tijesta bez dodavanja HPMC -a smanjila se s 0,968 ± 0,006 (zamrzavanje tijekom 0 dana) na 0,689 ± 0,022 (zamrzavanja); Smrznuto je s 2% HPMC dodao elastičnost parenih peciva izrađenih od tijesta, smanjila se s 1,176 ± 0,003 (zamrzavanje u trajanju od 0 dana) na 0,962 ± 0,003 (zamrzavanje tijekom 60 dana). Očito su se povećanje stope tvrdoće i brzina smanjenja elastičnosti smanjili s povećanjem dodane količine HPMC u smrznutom tijestu tijekom razdoblja zamrznutog skladištenja. This shows that the addition of HPMC can effectively improve the quality of steamed bread. In addition, Table 2.5 lists the effects of HPMC addition and frozen storage time on other texture indexes of steamed bread. ) had no significant change (P>0.05); however, at 0 days of freezing, with the increase of HPMC addition, the Gumminess and Chewiness decreased significantly (P

On the other hand, with the prolongation of freezing time, the cohesion and restoring force of steamed bread decreased significantly. Za parni kruh napravljen od smrznutog tijesta bez dodavanja HPMC-a, njegova kohezija je povećana za O. 86-4-0,03 g (smrznuto skladištenja 0 dana) smanjena je na 0,49+0,06 g (smrznuto skladištenja 60 dana), dok je sila za skladištenje 0,48 (fromzen) smanjena s 0,48+0,04 g). however, for steamed buns made from frozen dough with 2% HPMC added, the cohesion was reduced from 0.93+0.02 g (0 days frozen) to 0.61+0.07 g (frozen storage for 60 days), while the restoring force was reduced from 0.53+0.01 g (frozen storage for 0 days) to 0.27+4-0.02 (frozen storage for 60 days). In addition, with the prolongation of frozen storage time, the stickiness and chewiness of steamed bread increased significantly. For the steamed bread made from frozen dough without adding HPMC, the stickiness was increased by 336.54+37. 24 (0 days of frozen storage) increased to 1232.86±67.67 (60 days of frozen storage), while chewiness increased from 325.76+34.64 (0 days of frozen storage) to 1005.83+83.95 (frozen for 60 days); Međutim, za pare peciva napravljene od smrznutog tijesta s dodanim 2% HPMC -a, ljepljivost se povećala sa 206,62+1 1,84 (smrznuta tijekom 0 dana) na 472,84. 96+45.58 (frozen storage for 60 days), while chewiness increased from 200.78+10.21 (frozen storage for 0 days) to 404.53+31.26 (frozen storage for 60 days). This shows that the addition of HPMC can effectively inhibit the changes in the texture properties of steamed bread caused by freezing storage. Pored toga, promjene u svojstvima teksture kruha na pari uzrokovane skladištenjem zamrzavanja (poput povećanja ljepljivosti i žvakanja i smanjenja sile oporavka) Postoji i određena unutarnja korelacija s promjenom volumena specifičnog za pare. Stoga se svojstva tijesta (npr. Farinalnost, izduživanje i reološka svojstva) mogu poboljšati dodavanjem HPMC -a smrznutom tijestu, a HPMC inhibira stvaranje, rast i preraspodjelu kristala leda (proces rekristalizacije), što je zamrzano tijesto ukinuto.

Hydroxypropyl methylcellulose (HPMC) is a kind of hydrophilic colloid, and its application research in frozen dough with Chinese-style pasta food (such as steamed bread) as the final product is still lacking. The main purpose of this study is to evaluate the effect of HPMC improvement by investigating the effect of HPMC addition on the processing properties of frozen dough and the quality of steamed bread, so as to provide some theoretical support for the application of HPMC in steamed bread and other Chinese-style flour products. The results show that HPMC can improve the farinaceous properties of the dough. When the addition amount of HPMC is 2%, the water absorption rate of the dough increases from 58.10% in the control group to 60.60%; 2 min increased to 12.2 min; at the same time, the dough formation time decreased from 2.1 min in the control group to 1.5 mill; the weakening degree decreased from 55 FU in the control group to 18 FU. In addition, HPMC also improved the tensile properties of the dough. With the increase in the amount of HPMC added, the elongation of the dough increased significantly; significantly reduced. Osim toga, tijekom razdoblja zamrznutog skladištenja, dodavanje HPMC -a smanjilo je brzinu povećanja udjela vode zamrzavanja u tijestu, čime je inhibiralo oštećenje strukture mreže tijesta uzrokovanu kristalizacijom leda, održavajući relativnu stabilnost viskoelastičnosti tijesta i integriteta mrežne strukture, poboljšavajući stabilnost mreže Dough. The quality of the final product is guaranteed.


Poglavlje 3 Učinci dodavanja HPMC -a na strukturu i svojstva glutena pšenice u uvjetima zamrzavanja
3.1 Uvod
Pšenični gluten je najzastupljeniji protein za skladištenje u pšeničnim zrncima, što čini više od 80% ukupnog proteina. According to the solubility of its components, it can be roughly divided into glutenin (soluble in alkaline solution) and gliadin (soluble in alkaline solution). U otopini etanola). Među njima je molekularna masa (MW) glutenina čak 1x107Da, a ima dvije podjedinice, koje mogu tvoriti intermolekularne i intramolekularne disulfidne veze; while the molecular weight of gliadin is only 1x104Da, and there is only one subunit, which can form molecules Internal disulfide bond [100]. Campos, Steffe, & Ng (1 996) divided the formation of dough into two processes: energy input (mixing process with dough) and protein association (formation of dough network structure). Općenito se vjeruje da tijekom stvaranja tijesta glutenin određuje elastičnost i strukturnu čvrstoću tijesta, dok gliadin određuje viskoznost i fluidnost tijesta [102]. Može se vidjeti da gluten protein ima neophodnu i jedinstvenu ulogu u stvaranju strukture mreže tijesta, a tijesto obdaruje kohezijom, viskoelastičnošću i apsorpcijom vode.
Pored toga, s mikroskopskog stajališta, stvaranje trodimenzionalne mrežne strukture tijesta popraćeno je stvaranjem intermolekularnih i intramolekularnih kovalentnih veza (poput disulfidnih veza) i nekovalentnih veza (poput vodikovih veza, hidrofobnih sila) [103]. Although the energy of the secondary bond

Za smrznuto tijesto, u uvjetima smrzavanja, stvaranje i rast kristala leda (proces kristalizacije i rekristalizacije) uzrokovat će da se struktura mrežne mreže fizički stisne, a njegov strukturni integritet će se uništiti i mikroskopski. Praćena promjenama u strukturi i svojstvima proteina glutena [105'1061. Kao Zhao, et a1. (2012) found that with the prolongation of freezing time, the molecular weight and molecular gyration radius of gluten protein decreased [107J, which indicated that gluten protein partially depolymerized. In addition, the spatial conformational changes and thermodynamic properties of gluten protein will affect the dough processing properties and product quality. Stoga je, u procesu skladištenja zamrzavanja, od određenog značaja istraživanja istražiti promjene vodenog stanja (stanje kristala leda) i strukturu i svojstva proteina glutena u različitim uvjetima vremena skladištenja zamrzavanja.
Kao što je spomenuto u predgovoru, kao hidrokoloid derivata celuloze, primjena hidroksipropil metilceluloze (HPMC) u smrznutom tijestu nije mnogo proučavana, a istraživanje njegovog mehanizma za djelovanje je još manje.
Therefore, the purpose of this experiment is to use the wheat gluten dough (Gluten Dough) as the research model to investigate the content of HPMC (0, 0.5%) under different freezing storage time (0, 15, 30, 60 days) , 1%, 2%) on the state and distribution of water in the wet gluten system, gluten protein rheological properties, thermodynamic properties, and its physicochemical properties, and then Istražite razloge promjena u svojstvima obrade smrznutog tijesta i ulogu problema s HPMC mehanizmom kako biste poboljšali razumijevanje povezanih problema.

3.2.1 Eksperimentalni materijali



Otkriće. R3 Rheometer
DSC. Q200 Diferencijalno skeniranje kalorimetra
PQ00 1 NMR instrument s niskim poljem
722E Spektrofotometar
JSM. 6490LV volfram -filament skeniranje elektronskog mikroskopa
HH digitalna stalna temperatura vodena kupaonica
BC/BD. 272Sc hladnjak
BCD. 201LCT hladnjak
MI. 5 Ultra-mikroelektronska ravnoteža

Nicolet 67 Fourier transformacijski infracrveni spektrometar
Fd. 1b. 50 sušilica za zamrzavanje vakuuma
KDC. 160h brze hladnjake centrifuge
Thermo Fisher FC čitač mikroploča pune valne duljine
PB. Model 10 PH metar
Myp ll. Tip 2 magnetska miješalica
Mx. S tipa Eddy struje oscilator

KJELTEC TM 8400 AUTOMATSKI KJELDAHL ANALIZAK ANALIZA
Proizvođač


Shanghai Niumet Company
Shanghai Spectrum Instrument Co., Ltd.
Nippon Electronics Manufacturing Co., Ltd.

Qingdao haier grupa
Hefei Mei Ling Co., Ltd.
Sartorius, Njemačka
Thermo Fisher, SAD

Beijing Bo Yi Kang Experimental Instrument Co., Ltd.
Anhui Zhong Ke Zhong Jia Scientific Instrument Co., Ltd.
Thermo Fisher, SAD
Njemačka Certoris

SciLogex, SAD
Huangshi Hengfeng Medical Equipment Co., Ltd.
Danska Foss Company

Svi kemijski reagensi korišteni u eksperimentima bili su analitičke stupnja.

3.2.4.1 Određivanje osnovnih komponenti glutena

3.2.4.3. Određivanje reoloških svojstava mase vlažne glutena
When the corresponding freezing time is over, take out the frozen wet gluten mass and place it in a 4°C refrigerator to equilibrate for 8 hours. Then, take out the sample and place it at room temperature until the sample is completely thawed (this method of thawing the wet gluten mass is also applicable to later part of the experiments, 2.7.1 and 2.9). A sample (about 2 g) of the central area of ​​the melted wet gluten mass was cut and placed on the sample carrier (Bottom Plate) of the rheometer (Discovery R3). Pomicanje naprezanja) Da bi se odredila regija linearne viskoelastičnosti (LVR), specifični eksperimentalni parametri postavljeni su na sljedeći način - učvršće je paralelna ploča s promjerom od 40 mlina, jaz je postavljen na 1000 mRN, a temperatura je postavljena na 25 ° C, raspon skeniranja soja je 0,01%. 100%, the frequency is set to 1 Hz. Then, after changing the sample, let it stand for 10 minutes, and then perform dynamic
Frekvencijski pometanje, specifični eksperimentalni parametri postavljeni su na sljedeći način - soj je 0,5% (na LVR), a raspon frekvencijskog pomicanja 0,1 Hz. 10 Hz, while other parameters are the same as the strain sweep parameters. Scanning data is acquired in logarithmic mode, and 5 data points (plots) are recorded in the rheological curve for every 10-fold increase in frequency, so as to obtain the frequency as the abscissa, the storage modulus (G') and the loss modulus (G') is the rheological discrete curve of the ordinate. Vrijedno je napomenuti da nakon svakog puta uzorak pritisne stezaljku, višak uzorka treba lagano strugati nožama, a sloj parafinskog ulja nanosi se na rub uzorka kako bi se spriječila vlaga tijekom eksperimenta. gubitka. Svaki je uzorak ponovljen tri puta.



Uzorak vlažnog glutena od 15 mg izvagan je i zapečaćen u aluminijskom loncu (pogodno za uzorke tekućine). The determination procedure and parameters are as follows: equilibrate at 20°C for 5 min, then drop to .30°C at a rate of 10°C/min, keep the temperature for 10 min, and finally increase to 25°C at a rate of 5°C/min, purge the gas (Purge Gas) was nitrogen (N2) and its flow rate was 50 mL/min, and a blank sealed aluminum crucible was used as a reference. Dobivena DSC krivulja analizirana je korištenjem softvera za analizu Universal Analysis 2000, analizom vrhova smještenih oko 0 ° C. Integralni za dobivanje entalpije topljenja ledenih kristala (Yu Day). Zatim se udio vode (CFW) izračunava sljedećim formulom [85-86]:

Među njima, tri, predstavlja latentnu toplinu vlage, a njegova vrijednost je 334 J/g; MC represents the total moisture content of the wet gluten measured (measured according to GB 50093.2010 [. 78]). Each sample was replicated three times.
(2) Određivanje vršne temperature toplinske denaturacije (TP) proteina pšeničnog glutena
Freeze-dry the frozen-storage-treated sample, grind it again, and pass it through a 100-mesh sieve to obtain gluten protein powder (this solid powder sample is also applicable to 2.8). Uzorak proteina od 10 mg glutena izvagan je i zapečaćen u aluminijskom loncu (za čvrste uzorke). The DSC measurement parameters were set as follows, equilibrated at 20 °C for 5 min, and then increased to 100 °C at a rate of 5 °C/min, using nitrogen as the purge gas, and its flow rate was 80 mL/min. Using a sealed empty crucible as a reference, and use the analysis software Universal Analysis 2000 to analyze the obtained DSC curve to obtain the peak temperature of thermal denaturation of wheat gluten protein (Yes). Each sample is replicated three times.
3.2.4.5 Određivanje slobodnog sadržaja sulfhidrila (c) glutena od pšenice
The content of free sulfhydryl groups was determined according to the method of Beveridg, Toma, & Nakai (1974) [Hu], with appropriate modifications. Odmjerite 40 mg uzorka proteina pšeničnog glutena, dobro ga protresite i rastjerati u 4 ml dodecil sulfonata
Sodium Sodium (SDS). Tris-hidroksimetil aminometan (Tris). Glycine (Gly). Tetraacetic acid 7, amine (EDTA) buffer (10.4% Tris, 6.9 g glycine and 1.2 g EDTA/L, pH 8.0, abbreviated as TGE, and then 2.5% SDS It was added to the above TGE solution (that is, prepared into SDS-TGE buffer), incubated at 25°C for 30 min, and shaken every 10 min. Then, the supernatant was obtained after centrifugation for 10 min na 4 ° C i 5000 × g., Sadržaj proteina u supernatantu odredio je metodu Coomassie Brilliance Blue (G.250). Inkubacija u vodenoj kupelji od 25 ℃, dodajte 412 nm apsorpciju, a gornji međuspremnik korišten je kao prazna kontrola.

Among them, 73.53 is the extinction coefficient; A je vrijednost apsorpcije; D is the dilution factor (1 here); G is the protein concentration. Each sample was replicated three times.
3.2.4.6 Određivanje 1h I "2 vrijeme opuštanja
According to Kontogiorgos, Goff, & Kasapis (2007) method [1111, 2 g of wet gluten mass was placed in a 10 mm diameter nuclear magnetic tube, sealed with plastic wrap, and then placed in a low-field nuclear magnetic resonance apparatus to measure the transverse relaxation time (n), the specific parameters are set as follows: 32 ℃ equilibrium for 3 min, the field strength is 0.43 T, the resonance frequency is 18.169 Hz, and the pulse sequence is Carr-Purcell-Meiboom-Gill (CPMG), and the pulse durations of 900 and 1 800 were set to 13¨s and 25¨s , respectively, and the pulse interval r was as small as possible to reduce the interference and diffusion of the decay curve. U ovom je eksperimentu postavljen na O. 5 m s. Svako je ispitivanje skenirano 8 puta kako bi se povećao omjer signal-šum (SNR), s intervalom od 1 s između svakog skeniranja. Vrijeme opuštanja dobiva se iz sljedeće integralne jednadžbe:

Među njima je M funkcija eksponencijalnog zbroja propadanja amplitude signala s vremenom (t) kao neovisnu varijablu; Yang) je funkcija gustoće broja vodika s vremenom opuštanja (d) kao neovisnu varijablu.
Koristeći algoritam kontinuiranog u softveru za analizu Provencher u kombinaciji s Laplace inverznom transformacijom, inverzija se provodi kako bi se dobila krivulja kontinuirane distribucije. Svaki je uzorak ponovljen tri puta
3.2.4.7 Određivanje sekundarne strukture proteina glutena od pšeničnog glutena

Use OMNIC software to perform automatic baseline correction and advanced ATR correction on the obtained full wavenumber infrared spectrum, and then use Peak. Fit 4.12 software performs baseline correction, Fourier deconvolution and second derivative fitting on the amide III band (1350 cm-1.1200 cm'1) until the fitted correlation coefficient (∥) reaches 0. 99 or more, the integrated peak area corresponding to the secondary structure of each protein is finally obtained, and the relative content of each secondary structure is calculated. Iznos (%), to jest, vršna površina/ukupna vrha. Za svaki uzorak izvedene su tri paralele.
3.2.4.8 Određivanje površinske hidrofobnosti proteina glutena
Prema metodi Kato & Nakai (1980) [112], naftalen sulfonska kiselina (ANS) korištena je kao fluorescentna sonda za određivanje površinske hidrofobnosti pšeničnog glutena. Weigh 100 mg gluten protein solid powder sample, disperse it in 15 mL, 0.2M, pH 7.0 phosphate buffered saline (PBS), stir magnetically for 20 min at room temperature, and then stir at 7000 rpm, 4 " Under the condition of C, centrifuge for 10 min, and take the supernatant. Similarly, use Coomassie brilliant blue method to measure the protein content in the supernatant, then according to the measurement Rezultati, supernatant je razrijeđen s PBS -om za zauzvrat 5 gradijenata koncentracije, a koncentracija proteina je u rasponu 0 .02.0.5 mg/ml.
Absorb 40 IL ANS solution (15.0 mmol/L) was added to each gradient sample solution (4 mL), shaken and shaken well, then quickly moved to a sheltered place, and 200 "L drops of light were drawn from the sample tube with low concentration to high concentration in turn. Add it to a 96-well microtiter plate, and use an automatic microplate reader to measure the fluorescence intensity values with 365 nm as excitation light and 484 AM kao hidrofobnost emisije.

Nakon smrzavanja vlažne mase glutena bez dodavanja HPMC-a i dodavanja 2% HPMC-a koji je bio smrznut 0 dana i 60 dana, neki su uzorci izrezani, raspršeni zlatom 90 s propuštenom elektronom, a zatim su smješteni u skeniranje elektronskog mikroskopa (JSM.6490LV). Izvedeno je morfološko promatranje. Napon ubrzanja postavljen je na 20 kV, a povećanje je bilo 100 puta.
3.2.4.10 obrada podataka
All results are expressed as mean 4-standard deviation, and the above experiments were repeated at least three times except for scanning electron microscopy. Koristite Origin 8.0 za crtanje grafikona i koristite SPSS 19.0 za jedan. Način analize varijance i Duncanov test s višestrukim rasponom, razina značajnosti bila je 0,05.
3. Rezultati i rasprava
3.3.1 Učinci količine dodavanja HPMC -a i vrijeme skladištenja zamrzavanja na reološka svojstva mase mokrog glutena
Rheological properties are an effective way to reflect the structure and properties of food materials and to predict and evaluate product quality [113J. As we all know, gluten protein is the main material component that gives dough viscoelasticity. As shown in Figure 3.1, the dynamic frequency sweep (0.1.10 Hz) results show that the storage modulus (elastic modulus, G') of all wet gluten mass samples is greater than the loss modulus (viscous modulus) , G”), therefore, the wet gluten mass showed solid-like rheological characteristics (Figure 3.1, AD). This result also shows that the intermolecular and intramolecular glutenin The mutual Uskladačka struktura formirana kovalentnom ili nekovalentnom interakcijom je okosnica strukture mreže tijesta [114]. HPMC je dodao različite stupnjeve smanjenja (Sl. 3.1, 115). Sexual differences (Figure 3.1, D). To ukazuje da je trodimenzionalna mrežna struktura vlažne glutenske mase bez HPMC-a uništena ledenim kristalima formiranim tijekom procesa zamrzavanja, što je u skladu s rezultatima koje su pronašli Kontogiorgos, Goff, & Kasapis (2008), koji je vjerovao da je vrijeme produženog zamrzavanja uzrokovalo funkcionalnost i stabilnost DUGH-a.

Slika 3．1 Utjecaj dodavanja HPMC -a i smrznuto skladištenja na reološka svojstva tijesta za gluten

During frozen storage, the moisture in the wet gluten mass crystallizes because the temperature is lower than its freezing point, and it is accompanied by a recrystallization process over time (due to fluctuations in temperature, migration and distribution of moisture, changes in moisture state, etc.) , which in turn leads to the growth of ice crystals (increase in size), which makes the ice crystals located in the dough network structure destroy their integrity and break some chemical Veze kroz fizičku ekstruziju. Međutim, uspoređujući s usporedbom skupina pokazalo je da dodavanje HPMC -a može učinkovito inhibirati stvaranje i rast kristala leda, štiteći na taj način integritet i čvrstoću strukture glutenske mreže, a unutar određenog raspona, inhibitorni učinak bio je pozitivno povezan s količinom dodanog HPMC -a.
3.3.2 Učinci količine dodavanja HPMC -a i vrijeme skladištenja zamrzavanja na sadržaj vlage zamrzivača (CFW) i toplinsku stabilnost
3.3.2.1 Učinci količine dodavanja HPMC -a i zamrzavanje vremena za pohranu na zamrzivi sadržaj vlage (CFW) u mokrom tijestu za gluten
Ice crystals are formed by the phase transition of freezable water at temperatures below its freezing point. Therefore, the content of freezable water directly affects the number, size and distribution of ice crystals in the frozen dough. The experimental results (Table 3.2) show that as the freezing storage time is extended from 0 days to 60 days, the wet gluten mass Chinese silicon gradually becomes larger, which is consistent with the research results of others [117'11 81]. Posebno, nakon 60 dana zamrznutog skladištenja, entalpija faznog prijelaza (dana) mokrog glutena bez HPMC -a porasla je sa 134,20 J/g (0 d) na 166,27 j/g (60 d), to jest, povećanje se povećalo za 23,90%, povećanje za Freezable na 40. However, for the samples supplemented with 0.5%, 1% and 2% HPMC, after 60 days of freezing, the C-chat increased by 20.07%, 16, 63% and 15.96%, respectively, which is consistent with Matuda, et a1. (2008) found that the melting enthalpy (Y) of the samples with added hydrophilic colloids decreased compared with the blank samples [119].
The increase in CFW is mainly due to the recrystallization process and the change of the gluten protein conformation, which changes the state of water from non-freezable water to freezable water. This change in moisture state allows ice crystals to be trapped in the interstices of the network structure, the network structure (pores) gradually become larger, which in turn leads to greater squeezing and destruction of the walls of the pores. However, the significant difference of 0w between the sample with a certain content of HPMC and the blank sample shows that HPMC can keep the water state relatively stable during the freezing process, thereby reducing the damage of ice crystals to the gluten network structure, and even inhibiting the quality of the product. pogoršanje.


Toplinska stabilnost glutena ima važan utjecaj na stvaranje zrna i kvalitetu proizvoda termički obrađene tjestenine [211]. Na slici 3.2 prikazana je dobivena DSC krivulja s temperaturom (° C) kao abscissa i toplinskog protoka (MW) kao ordinata. Eksperimentalni rezultati (tablica 3.3) otkrili su da je temperatura denaturacije topline proteina glutena bez zamrzavanja i bez dodavanja I-IPMC bila 52,95 ° C, što je bilo u skladu s Leon, et A1. (2003) and Khatkar, Barak, & Mudgil (2013) reported very similar results [120m11. With the addition of 0% unfrozen, O. Compared with the heat denaturation temperature of gluten protein with 5%, 1% and 2% HPMC, the heat deformation temperature of gluten protein corresponding to 60 days increased by 7.40℃, 6.15℃, 5.02℃ and 4.58℃, respectively. Obviously, under the condition of the same freezing storage time, the increase of denaturation peak temperature (N) decreased sequentially with the increase of HPMC addition. This is consistent with the change rule of the results of Cry. In addition, for the unfrozen samples, as the amount of HPMC added increases, the N values ​​decrease sequentially. To može biti posljedica intermolekularne interakcije između HPMC s molekularnoj površinskoj aktivnosti i glutena, poput stvaranja kovalentnih i nevalentnih veza [122J].

Napomena: Različita slova s ​​malim slovima u istom stupcu ukazuju na značajnu razliku (p <0,05), Myers (1990) je vjerovao da viši ANG znači da molekula proteina izlaže više hidrofobnih skupina i sudjeluje u procesu denaturacije molekule [1231]. Stoga je više hidrofobnih skupina u glutenu bilo izloženo tijekom zamrzavanja, a HPMC bi mogao učinkovito stabilizirati molekularnu konformaciju glutena.

Slika 3．2 Tipični DSC termogrami glutenskih proteina s 0 ％ HPMC (a) ； s O．5 ％ HPMC (b) ； s 1 ％ HPMC (c) ； s 2 ％ hpmc (d) nakon različitih vremena zamrzavanja ， na 60D na ， ， ， ， u svakoj od najviših zakrivljenosti Note: A is the DSC curve of wheat gluten without adding HPMC; B is the addition of O. DSC curve of wheat gluten with 5% HPMC; C is the DSC curve of wheat gluten with 1% HPMC; D je DSC krivulja pšeničnog glutena s 2% HPMC 3.3.3 Učinci količine dodavanja HPMC-a i vremena zamrzavanja na slobodni sulfhidrilni sadržaj (C-SH) Intermolekularne i intramolekularne kovalentne veze vrlo su važne za stabilnost strukture mreže tijesta. A disulfide bond (-SS-) is a covalent linkage formed by dehydrogenation of two free sulfhydryl groups (.SH). Glutenin is composed of glutenin and gliadin, the former can form intramolecular and intermolecular disulfide bonds, while the latter can only form intramolecular disulfide bonds [1241] Therefore, disulfide bonds are an intramolecular/intermolecular disulfide bond. important way of cross-linking. Compared to adding 0%, O. The C-SH of 5% and 1% HPMC without freezing treatment and the C-SH of gluten after 60 days of freezing have different degrees of increase respectively. Specifically, the face with no HPMC added gluten C. SH increased by 3.74 "mol/g to 8.25 "mol/g, while C.sh, shellfish, with gluten supplemented with 0.5% and 1% HPMC increased by 2.76 "mol/g to 7.25""mol/g and 1.33 "mol/g to 5.66 "mol/g (Fig. 3.3). Zhao, et a1. (2012) found that after 120 days of frozen storage, the content of free thiol groups increased significantly [ 1071. It is worth noting that the C-SH of gluten protein was significantly lower than that of other frozen storage periods when the freezing period was 15 days, which may be attributed to the freezing shrinkage effect of gluten protein structure, which makes the More intermolecular and intramolecular disulfide bonds were locally formed in a shorter freezing time [1161. Wang, et a1. (2014) found that the C-SH of glutenin-rich proteins was also significantly increased after 15 days of freezing. Decreased [1251. However, the gluten protein supplemented with 2% HPMC did not increase significantly except for C-SH, which also decreased significantly at 15 days, with the extension of freezing time.

Fig 3．3 Effect of HPMC addition and frozen storage on the content of free-SH for gluten proteins As mentioned above, freezable water can form ice crystals at low temperatures and distribute in the interstices of the gluten network. Stoga, s produljenjem vremena smrzavanja, ledeni kristali postaju veći, što ozbiljnije stisne strukturu glutenskih proteina i dovodi do lomljenja nekih intermolekularnih i intramolekularnih disulfidnih veza, što povećava sadržaj slobodnih sulfhidrilnih skupina. On the other hand, the experimental results show that HPMC can protect the disulfide bond from the extrusion damage of ice crystals, thereby inhibiting the depolymerization process of gluten protein. 3.3.4 Učinci količine dodavanja HPMC -a i vrijeme skladištenja zamrzavanja na vrijeme poprečnog opuštanja (T2) mase mokrog glutena Raspodjela vremena poprečnog opuštanja (T2) može odražavati model i dinamički proces migracije vode u prehrambenim materijalima [6]. Figure 3.4 shows the distribution of wet gluten mass at 0 and 60 days with different HPMC additions, including 4 main distribution intervals, namely 0.1.1 ms (T21), 1.10 ms (T22), 10.100 ms (dead;) and 1 00-1 000 ms (T24). Bosmans et al. (2012) found a similar distribution of wet gluten mass [1261], and they suggested that protons with relaxation times below 10 ms could be classified as rapidly relaxing protons, which are mainly derived from poor mobility the bound water, therefore, may characterize the relaxation time distribution of bound water bound to a small amount of starch, while Dang may characterize the relaxation time distribution of bound water bound to gluten protein. In addition, Kontogiorgos (2007) - t11¨, the "strands" of the gluten protein network structure are composed of several layers (Sheets) about 5 nm apart, and the water contained in these layers is limited water (or Bulk water, phase water), the mobility of this water is between the mobility of bound water and free water. And T23 can be attributed to the relaxation time distribution of restricted water. The T24 distribution (>100 ms) has a long relaxation time, so it characterizes free water with strong mobility. This water exists in the pores of the network structure, and there is only a weak capillary force with the gluten protein system.


Napomena: A i B predstavljaju krivulje raspodjele poprečnog opuštanja (N) distribucije mokrog glutena s različitim sadržajem HPMC -a dodanih za 0 dana i 60 dana u skladištu zamrzavanja, odnosno
Uspoređujući vlažna gluten tijesta s različitim dodavanjem količina HPMC -a pohranjenih u smrznutom skladištu 60 dana, odnosno nesuzvanom skladišnom skladišnom prostoru, utvrđeno je da ukupna područja distribucije T21 i T24 nije pokazala značajnu razliku, što ukazuje na to da dodavanje HPMC -a nije značajno povećalo relativnu količinu vezane vode. Sadržaj, koji može biti posljedica činjenice da glavne tvari koje vežu vodu (gluten protein s malom količinom škroba) nisu značajno promijenjene dodavanjem male količine HPMC-a. S druge strane, uspoređujući područja distribucije T21 i T24 mase mokrog glutena s istom količinom HPMC -a dodane za različita vremena skladištenja zamrzavanja, također nema značajne razlike, što ukazuje da je vezana voda relativno stabilna tijekom postupka skladištenja zamrzavanja i negativno utjecati na okoliš. Promjene su manje osjetljive i manje pogođene.
However, there were obvious differences in the height and area of ​​T23 distribution of wet gluten mass that was not frozen and contained different HPMC additions, and with the increase of addition, the height and area of ​​T23 distribution increased (Fig. 3.4). This change shows that HPMC can significantly increase the relative content of limited water, and it is positively correlated with the added amount within a certain range. In addition, with the extension of freezing storage time, the height and area of ​​T23 distribution of the wet gluten mass with the same HPMC content decreased to varying degrees. Therefore, compared with bound water, limited water showed a certain effect on freezing storage. Osjetljivost. This trend suggests that the interaction between the gluten protein matrix and the confined water becomes weaker. To može biti zbog toga što je izloženo više hidrofobnih skupina tijekom zamrzavanja, što je u skladu s mjerenjima temperature vršne toplinske denaturacije. In particular, the height and area of ​​the T23 distribution for the wet gluten mass with 2% HPMC addition did not show a significant difference. This indicates that HPMC can limit the migration and redistribution of water, and can inhibit the transformation of the water state from the restricted state to the free state during the freezing process.
In addition, the height and area of ​​the T24 distribution of the wet gluten mass with different contents of HPMC were significantly different (Fig. 3.4, A), and the relative content of free water was negatively correlated with the amount of HPMC added. This is just the opposite of the Dang distribution. Therefore, this variation rule indicates that HPMC has water holding capacity and converts free water to confined water. Međutim, nakon 60 dana zamrzavanja, visina i površina raspodjele T24 povećali su se u različitom stupnju, što je ukazivalo da se vodeno stanje promijenilo iz ograničene vode u stanje slobodnog protoka tijekom procesa zamrzavanja. To je uglavnom zbog promjene konformacije proteina glutena i uništavanja jedinice "sloja" u strukturi glutena, što mijenja stanje zatvorene vode sadržane u njoj. Iako se sadržaj zamrzavajuće vode određene DSC -om također povećava s produljenjem vremena zamrzavanja, međutim, zbog razlike u metodama mjerenja i načela karakterizacije dvaju, zamrzavajuća voda i slobodna voda nisu u potpunosti ekvivalentni. For the wet gluten mass added with 2% HPMC, after 60 days of freezing storage, none of the four distributions showed significant differences, indicating that HPMC can effectively retain the water state due to its own water-holding properties and its interaction with gluten. and stable liquidity.
3.3.5 Učinci količine dodavanja HPMC -a i vrijeme skladištenja zamrzavanja na sekundarnu strukturu proteina glutena
Generally speaking, the secondary structure of protein is divided into four types, α-Spiral, β-folded, β-Corners and random curls. Najvažnije sekundarne veze za stvaranje i stabilizaciju prostorne konformacije proteina su vodikove veze. Therefore, protein denaturation is a process of hydrogen bond breaking and conformational changes.
Fourier transform infrared spectroscopy (FT-IR) has been widely used for high-throughput determination of the secondary structure of protein samples. The characteristic bands in the infrared spectrum of proteins mainly include, amide I band (1700.1600 cm-1), amide II band (1600.1500 cm-1) and amide III band (1350.1200 cm-1). U skladu s tim, vrh amida I potječe od vibracije istezanja karbonilne skupine (-c = o-.), Amidni II pojas je uglavnom posljedica vibracije savijanja amino skupine (-NH-) [1271], a amidni III pojas i amino-savijanje vibracije i .cn-．shin-．shin-ashndhsh. to changes in protein secondary structure [128'1291. Although the above three characteristic bands are all characteristic infrared absorption peaks of proteins, the specific In other words, the absorption intensity of amide II band is lower, so the semi-quantitative accuracy of protein secondary structure is poor; while the peak absorption intensity of amide I band is higher, so many researchers analyze the secondary structure of protein by this band [ 1301, but the absorption peak of water and the amide I band are overlapped at about 1640 cm. 1 wavenumber (Overlapped), which in turn affects the accuracy of the results. Therefore, the interference of water limits the determination of the amide I band in protein secondary structure determination. U ovom eksperimentu, kako bi se izbjegla smetnja vode, dobiveni su relativni sadržaji od četiri sekundarne strukture glutenskog proteina analizom pojasa Amide III. Peak position (wavenumber interval) of



Figure 3.5 is the infrared spectrum of the amide III band of gluten protein added with different contents of HPMC for 0 days after being frozen for 0 days after deconvolution and fitting of the second derivative. (2001) primijenio je drugi derivat kako bi odgovarao dekonvoluiranim vrhovima sa sličnim vrhovima [1321]. In order to quantify the relative content changes of each secondary structure, Table 3.5 summarizes the relative percentage content of the four secondary structures of gluten protein with different freezing times and different HPMC additions (corresponding peak integral area/peak total area).

Slika 3．5 Dekonvolucija amidnog pojasa III glutena s O ％ HPMC pri 0 d (a) ， s 2 ％ HPMC pri 0 d (b)

With the prolongation of frozen storage time, the secondary structure of gluten protein with different additions of HPMC changed to different degrees. Može se vidjeti da i smrznuto skladištenje i dodavanje HPMC -a utječu na sekundarnu strukturu glutenskog proteina. Bez obzira na količinu HPMC -a, B. Presavijena struktura je najdominantnija struktura, koja čini oko 60%. Nakon 60 dana smrznutog pohrane, dodajte 0%, OB gluten od 5% i 1% HPMC. The relative content of folds increased significantly by 3.66%, 1.87% and 1.16%, respectively, which was similar to the results determined by Meziani et al. (2011) [L33J]. Međutim, nije bilo značajne razlike tijekom zamrznutog skladištenja za gluten dopunjene 2% HPMC. Osim toga, kada se smrznite 0 dana, s povećanjem dodavanja HPMC -a, str. Relativni sadržaj nabora je malo porastao, posebno kada je količina dodavanja bila 2%, str. Relativni sadržaj nabora porastao je za 2,01%. D. Presavijena struktura može se podijeliti u intermolekularni p. Savijanje (uzrokovano agregacijom molekula proteina), antiparallal str. Presavijeni i paralelni str. Tri su podstrukture presavijene i teško je odrediti koja se podstruktura pojavljuje tijekom postupka zamrzavanja
promijenio. Some researchers believe that the increase in the relative content of the B-type structure will lead to an increase in the rigidity and hydrophobicity of the steric conformation [41], and other researchers believe that p. Povećanje presavijene strukture nastaje zbog dijela nove β-preklopne formacije praćeno slabljenjem strukturne čvrstoće održavane vodikovim vezanjem [421]. β- Povećanje presavijene strukture ukazuje na to da se protein polimerizira hidrofobnim vezama, što je u skladu s rezultatima vršne temperature toplinske denaturacije izmjerene DSC-om i raspodjelom poprečnog vremena opuštanja mjerene nuklearnom magnetskom rezonancom niskog polja. Denaturacija proteina. On the other hand, added 0.5%, 1% and 2% HPMC gluten protein α-whirling. The relative content of helix increased by 0.95%, 4.42% and 2.03% respectively with the prolongation of freezing time, which is consistent with Wang, et a1. (2014) found similar results [134]. 0 of gluten without added HPMC. Nije bilo značajnih promjena u relativnom sadržaju spirale tijekom smrznutog postupka skladištenja, već s povećanjem količine dodavanja zamrzavanja tijekom 0 dana. There were significant differences in the relative content of α-whirling structures.

Slika 3．6 Shematski opis izloženosti hidrofobnom dijelu (a) ， preraspodjela vode (b) ， i sekundarne strukturne promjene (c) u matrici glutena s povećanjem zamrznutog vremena skladištenja 【31'138】

All samples with the extension of freezing time, p. The relative contents of the corners were significantly reduced. This shows that β-turn is very sensitive to freezing treatment [135. 1361], and whether HPMC is added or not has no effect. Wellner, et a1. (2005) predložio je da je okret β-lanca proteina glutena povezan sa strukturom svemirske domene β-okretanja u lancu polipeptida glutenina [L 37]. Except that the relative content of random coil structure of gluten protein added with 2% HPMC had no significant change in frozen storage, the other samples were significantly reduced, which may be caused by the extrusion of ice crystals. In addition, when frozen for 0 days, the relative contents of α-helix, β-sheet and β-turn structure of gluten protein added with 2% HPMC were significantly different from those of gluten protein without HPMC. This may indicate that there is an interaction between HPMC and gluten protein, forming new hydrogen bonds and then affecting the conformation of the protein; or HPMC absorbs the water in the pore cavity of the protein space structure, which deforms the protein and leads to more changes between the subunits. zatvoriti. Povećanje relativnog sadržaja strukture β-lista i smanjenje relativnog sadržaja β-okretne i α-helix strukture u skladu su s gore navedenim nagađanjima. Tijekom postupka smrzavanja, difuzija i migracija vode i stvaranje kristala leda uništavaju vodikove veze koje održavaju konformacijsku stabilnost i izlažu hidrofobne skupine proteina. In addition, from the perspective of energy, the smaller the energy of the protein, the more stable it is. Na niskoj temperaturi, ponašanje samoorganizacije (savijanja i razvijanja) molekula proteina odvija se spontano i dovodi do konformacijskih promjena.

3.3.6 Učinci količine dodavanja HPMC -a i vrijeme skladištenja zamrzavanja na površinsku hidrofobnost proteina glutena
Protein molecules include both hydrophilic and hydrophobic groups. Generally, the protein surface is composed of hydrophilic groups, which can bind water through hydrogen bonding to form a hydration layer to prevent protein molecules from agglomerating and maintain their conformational stability. Unutrašnjost proteina sadrži više hidrofobnih skupina za formiranje i održavanje sekundarne i tercijarne strukture proteina kroz hidrofobnu silu. Denaturation of proteins is often accompanied by exposure of hydrophobic groups and increased surface hydrophobicity.
Tab3．6 Utjecaj dodavanja HPMC -a i smrznuto skladištenja na površinsku hidrofobnost glutena

NAPOMENA: U istom retku nalazi se natpisno pismo bez M i B, što ukazuje da postoji značajna razlika (<0,05);
Različita slova natkripta u istom stupcu ukazuju na značajnu razliku (<0,05);
Nakon 60 dana zamrznutog skladištenja, dodajte 0%, O. Površinska hidrofobnost glutena s 5%, 1%i 2%HPMC povećala se za 70,53%, 55,63%, 43,97%i 36,69%(Tablica 3,6). Konkretno, površinska hidrofobnost proteina glutena bez dodavanja HPMC -a nakon što je smrznuta 30 dana značajno se povećala (P <0,05), a već je veća od površine proteina glutena s 1% i 2% HPMC -a nakon zamrzavanja tijekom 60 dana hidrofobnosti. At the same time, after 60 days of frozen storage, the surface hydrophobicity of gluten protein added with different contents showed significant differences. However, after 60 days of frozen storage, the surface hydrophobicity of gluten protein added with 2% HPMC only increased from 19.749 to 26.995, which was not significantly different from the surface hydrophobicity value after 30 days of frozen storage, and was always lower than other the value of the surface hydrophobicity of the sample. To ukazuje da HPMC može inhibirati denaturaciju proteina glutena, što je u skladu s rezultatima DSC određivanja vršne temperature toplinske deformacije. To je zato što HPMC može inhibirati uništavanje strukture proteina rekristalizacijom i zbog svoje hidrofilnosti,
HPMC se može kombinirati s hidrofilnim skupinama na površini proteina kroz sekundarne veze, mijenjajući tako površinska svojstva proteina, istovremeno ograničavajući izlaganje hidrofobnih skupina (tablica 3.6).

Kontinuirana struktura mreže glutena sadrži mnoge pore za održavanje plina ugljičnog dioksida proizvedenog kvascem tijekom procesa provjere tijesta. Therefore, the strength and stability of the gluten network structure are very important to the quality of the final product, such as specific volume, quality, etc. Structure and sensory assessment. From a microscopic point of view, the surface morphology of the material can be observed by scanning electron microscopy, which provides a practical basis for the change of the gluten network structure during the freezing process.

Slika 3．7 SEM Slike mikrostrukture tijesta glutena ， (a) Naznačeno je tijesto glutena s 0 ％ hpmc za 0d zamrznutog skladištenja ； (b) naznačeno tijesto glutena s 0 ％ hpmc za 60d ； (c) naznačenog glutena sa 2 ％ HPMC za 0D (hpmc za 0D ％ zas.
Note: A is the microstructure of gluten network without adding HPMC and frozen for 0 days; B je mikrostruktura mreže glutena bez dodavanja HPMC -a i smrznutih 60 dana; C is the microstructure of gluten network with 2% HPMC added and frozen for 0 days :D is the gluten network microstructure with 2% HPMC added and frozen for 60 days
Nakon 60 dana zamrznutog skladištenja, mikrostruktura mokre glutenske mase bez HPMC -a značajno je promijenjena (Sl. 3.7, AB). At 0 days, the gluten microstructures with 2% or 0% HPMC showed complete shape, large
Mala približna porozna morfologija slična spužvi. However, after 60 days of frozen storage, the cells in the gluten microstructure without HPMC became larger in size, irregular in shape, and unevenly distributed (Fig. 3.7, A, B), mainly due to the This is caused by the fracture of the "wall", which is consistent with the measurement results of the free thiol group content, that is, during the freezing process, the ice crystal squeezes and breaks the Disulfidna veza, koja utječe na snagu i integritet strukture. As reported by Kontogiorgos & Goff (2006) and Kontogiorgos (2007), the interstitial regions of the gluten network are squeezed due to freeze-shrinkage, resulting in structural disruption [138. 1391]. In addition, due to dehydration and condensation, a relatively dense fibrous structure was produced in the spongy structure, which may be the reason for the decrease in free thiol content after 15 days of frozen storage, because more disulfide bonds were generated and frozen storage. Struktura glutena nije bila teško oštećena kraće vrijeme, što je u skladu s Wang, et A1. (2014) primijetili su slične pojave [134]. At the same time, the destruction of the gluten microstructure leads to freer water migration and redistribution, which is consistent with the results of low-field time-domain nuclear magnetic resonance (TD-NMR) measurements. Some studies [140, 105] reported that after several freeze-thaw cycles, the gelatinization of rice starch and the structural strength of the dough became weaker, and the water mobility became higher. Nonetheless, after 60 days of frozen storage, the microstructure of gluten with 2% HPMC addition changed less, with smaller cells and more regular shapes than gluten without HPMC addition (Fig. 3.7, B, D). To nadalje ukazuje da HPMC može učinkovito inhibirati uništavanje strukture glutena rekristalizacijom.
3.4 Sažetak poglavlja
This experiment investigated the rheology of wet gluten dough and gluten protein by adding HPMC with different contents (0%, 0.5%, 1% and 2%) during freezing storage (0, 15, 30 and 60 days). properties, thermodynamic properties, and effects of physicochemical properties. The study found that the change and redistribution of water state during the freezing storage process significantly increased the freezable water content in the wet gluten system, which led to the destruction of the gluten structure due to the formation and growth of ice crystals, and ultimately caused the processing properties of the dough to be different. Deterioration of product quality. Rezultati skeniranja frekvencije pokazali su da se elastični modul i viskozni modul vlažne glutenske mase bez dodavanja HPMC značajno smanjio tijekom postupka skladištenja zamrzavanja, a skenirajući elektronski mikroskop pokazao je da je njegova mikrostruktura oštećena. Sadržaj slobodne sulfhidrilne skupine značajno je povećan, a njegova hidrofobna skupina bila je izloženija, što je značajno povećala temperaturu toplinske denaturacije i površinska hidrofobnost proteina glutena. Međutim, eksperimentalni rezultati pokazuju da dodavanje I-IPMC-a može učinkovito inhibirati promjene u strukturi i svojstvima vlažne glutenske mase i proteina glutena tijekom skladištenja zamrzavanja, a unutar određenog raspona, ovaj inhibitorni učinak pozitivno je koreliran s dodatkom HPMC-a. To je zato što HPMC može smanjiti pokretljivost vode i ograničiti povećanje sadržaja zamrzavanja vode, inhibirajući na taj način fenomen rekristalizacije i zadržati strukturu mreže gluten i prostornu konformaciju proteina relativno stabilno. This shows that the addition of HPMC can effectively maintain the integrity of the frozen dough structure, thereby ensuring product quality.
Poglavlje 4 Učinci dodavanja HPMC -a na strukturu i svojstva škroba pod smrznutim pohranom

Starch is a chain polysaccharide with glucose as the monomer. key) two types. S mikroskopskog stajališta, škrob je obično granularan, a veličina čestica pšeničnog škroba uglavnom je raspoređena u dva raspona od 2-10 Pro (B škrob) i 25-35 pm (škrob). Iz perspektive kristalne strukture, granule škroba uključuju kristalne regije i amorfne regije (JE, ne-kristalne regije), a kristalni oblici se dodatno podijele na vrste A, B i C (postaje V-tip nakon potpune želatinizacije). Generally, the crystalline region consists of amylopectin and the amorphous region consists mainly of amylose. To je zato što, pored Cana C (glavni lanac), amilopektin također ima bočne lance sastavljene od B (lanca grana) i C (ugljični lanca), zbog čega se amilopektin pojavljuje "nalik na drveće" u sirovom škrobu. The shape of the crystallite bundle is arranged in a certain way to form a crystal.
Starch is one of the main components of flour, and its content is as high as about 75% (dry basis). Istodobno, kao ugljikohidrat koji je široko prisutan u žitaricama, škrob je također glavni materijal izvora energije u hrani. U sustavu tijesta, škrob se uglavnom distribuira i pričvršćuje na mrežnu strukturu glutenskog proteina. Tijekom obrade i skladištenja, škrobovi često podvrgavaju fazama želatinizacije i starenja.
Među njima se želatinizacija škroba odnosi na proces u kojem se granule škroba postupno raspadaju i hidriraju u sustavu s visokim udjelom vode i u uvjetima grijanja. It can be roughly divided into three main processes. 1) Reversible water absorption stage; before reaching the initial temperature of gelatinization, the starch granules in the starch suspension (Slurry) keep their unique structure unchanged, and the external shape and internal structure basically do not change. Only very little soluble starch is dispersed in the water and can be restored to its original state. 2) nepovratna faza apsorpcije vode; as the temperature increases, water enters the gap between the starch crystallite bundles, irreversibly absorbs a large amount of water, causing the starch to swell, the volume expands several times, and the hydrogen bonds between the starch molecules are broken. It becomes stretched and the crystals disappear. Istodobno, fenomen birefringentnih škroba, tj. Malteški križ opažen pod polarizirajućim mikroskopom, počinje nestajati, a temperatura se u ovom trenutku naziva početna temperatura želatinazacije škroba. 3) Starch granule disintegration stage; starch molecules completely enter the solution system to form starch paste (Paste/Starch Gel), at this time the viscosity of the system is the largest, and the birefringence phenomenon completely disappears, and the temperature at this time is called the complete starch gelatinization temperature, the gelatinized starch is also called α-starch [141]. When the dough is cooked, the gelatinization of starch endows the food with its unique texture, flavor, taste, color, and processing characteristics.
In general, starch gelatinization is affected by the source and type of starch, the relative content of amylose and amylopectin in starch, whether starch is modified and the method of modification, addition of other exogenous substances, and dispersion conditions (such as The influence of salt ion species and concentration, pH value, temperature, moisture content, etc.) [142-150]. Stoga, kada se promijeni struktura škroba (površinska morfologija, kristalna struktura, itd.), Utjecati će na svojstva želatinizacije, reološka svojstva, svojstva starenja, probavljivost itd. Škroba u skladu s tim.
Many studies have shown that the gel strength of starch paste decreases, it is easy to age, and its quality deteriorates under the condition of freezing storage, such as Canet, et a1. (2005) proučavao je učinak temperature smrzavanja na kvalitetu pirea škroba krumpira; Ferrero, et a1. (1993) investigated the effects of freezing rate and different types of additives on the properties of wheat and corn starch pastes [151-156]. However, there are relatively few reports on the effect of frozen storage on the structure and properties of starch granules (native starch), which needs to be further explored. Smrznuto tijesto (isključujući unaprijed kuhano smrznuto tijesto) je u obliku negelatiniziranih granula pod stanjem smrznutog skladištenja. Therefore, studying the structure and structural changes of native starch by adding HPMC has a certain effect on improving the processing properties of frozen dough. značaj.
In this experiment, by adding different HPMC contents (0, 0.5%, 1%, 2%) to the starch suspension, the amount of HPMC added during a certain freezing period (0, 15, 30, 60 days) was studied. na strukturi škroba i njegovoj želatinizacijskoj utjecaju prirode.
4.2 Eksperimentalni materijali i metode
4.2.1 Eksperimentalni materijali
Pšenični škrob Binzhou Zhongyu Food Co., Ltd.; HPMC Aladdin (Shanghai) Chemical Reagent Co., Ltd.;
4.2.2 Eksperimentalni aparat

HH digitalna stalna temperatura vodena kupaonica
BSAL24S ELEKTRONSKI BALANS




KDC. 160h brze hladnjake centrifuge
Otkrivanje R3 rotacijski reometar

D/max2500v tipa X. Ray Difraktometar

Proizvođač

Sartorius, Njemačka

Hefei Meiling Co., Ltd.
Huangshi Hengfeng Medical Equipment Co., Ltd.




Rigaku Manufacturing Co., Ltd.
Huangshi Hengfeng Medical Equipment Co., Ltd.

4.2.3.1 Priprema i smrznuto skladištenje ovjesa škroba
Izvažite 1 g škroba, dodajte 9 ml destilirane vode, potpuno se protresite i miješajte kako biste pripremili 10% (w/w) ovjes škroba. Zatim stavite otopinu uzorka. 18 ℃ refrigerator, frozen storage for 0, 15 d, 30 d, 60 d, of which 0 day is the fresh control. Add 0.5%, 1%, 2% (w/w) HPMC instead of the corresponding quality starch to prepare samples with different addition amounts, and the rest of the treatment methods remain unchanged.




Nacrtajte 1,5 ml otopine uzorka i dodajte je u središte faze uzorka reometra, izmjerite svojstva želatinizacije uzorka prema gore navedenim programskim parametrima i dobijte vrijeme (min) kao Abscissa, viskoznost (PA) i temperaturu (° C) kao krivulju želatinizacije naredbe. Prema GB/T 14490.2008 [158], odgovarajuća se dobivaju odgovarajuća karakteristična karakteristika želatinizacije - vršna viskoznost gelatinizacije (polje), vršna temperatura (ANG), minimalna viskoznost (visoka), konačna viskoznost (omjer) i vrijednost propadanja (propadanje). Value, BV) and regeneration value (Setback Value, SV), wherein, decay value = peak viscosity - minimum viscosity; setback value = final viscosity - minimum viscosity. Each sample was repeated three times.

The above gelatinized starch paste was subjected to the Steady Flow Test, according to the method of Achayuthakan & Suphantharika [1591, the parameters were set to: Flow Sweep mode, stand at 25°C for 10 min, and the shear rate scan range was 1) 0.1 S one. 100S～, 2) 100s～. 0.1 S～, the data is collected in logarithmic mode, and 10 data points (plots) are recorded every 10 times the shear rate, and finally the shear rate (Shear Rate, SI) is taken as the abscissa, and the shear viscosity ( Viscosity, pa ·s) is the rheological curve of the ordinate. Upotrijebite podrijetlo 8.0 za izvođenje nelinearnog uklapanja ove krivulje i dobiti relevantne parametre jednadžbe, a jednadžba zadovoljava Zakon o moći (zakon o moći), to jest, t/= k), ni, gdje je m viskoznost smicanja, indeks (pa · s), k je koeficijent konzistencije (protok), i jest.


Uzmite 2,5 g amiloida i pomiješajte ga s destiliranom vodom u omjeru 1: 2 kako biste napravili mlijeko škroba. Freeze at 18°C for 15 d, 30 d, and 60 d. Add 0.5, 1, 2% HPMC (w/w) to replace starch of the same quality, and other preparation methods remain unchanged. Nakon završetka tretmana zamrzavanja, izvadite ga, uravnotežite na 4 ° C 4 sata, a zatim otopite na sobnoj temperaturi dok se ne testira.

Take 1.5 mL of sample solution and place it on the sample stage of the rheometer (Discovery.R3), press down the 40 m/n plate with a diameter of 1500 mm, and remove the excess sample solution, and continue to lower the plate to 1000 mm, on motor, the speed was set to 5 rad/s and rotated for 1 min to fully homogenize the sample solution and avoid the sedimentation of starch granules. Temperaturno skeniranje počinje na 25 ° C, a završava na 5 c/min podignuto je na 95 ° C, čuvano 2 minute, a zatim spušteno na 25 ° C na 5 "c/min.
Sloj benzina lagano je nanesen na rub gornjeg škrobnog gela kako bi se izbjegao gubitak vode tijekom sljedećih eksperimenata. Referring to the Abebe & Ronda method [1601], an oscillatory strain sweep was firstly performed to determine the Linear Viscoelasticity Region (LVR), the strain sweep range was 0.01-100%, the frequency was 1 Hz, and the sweep was started after standing at 25 °C for 10 min.
Then, sweep the oscillation frequency, set the strain amount (strain) to 0.1% (according to the strain sweep results), and set the frequency range to O. 1 to 10 Hz. Svaki je uzorak ponovljen tri puta.
4.2.3.4 Termodinamička svojstva

After the corresponding freezing treatment time, the samples were taken out, thawed completely, and dried in an oven at 40 °C for 48 h. Konačno, mljeveno je kroz sito od 100 mreža za dobivanje uzorka čvrstog praha za upotrebu (pogodno za XRD testiranje). Vidi Xie, et A1. (2014) Metoda za pripremu uzoraka i određivanje termodinamičkih svojstava 1611, odmjerite 10 mg uzorka škroba u tekući aluminijski krug s ultra-mikro-analitičkom ravnotežom, dodajte 20 mg destilirane vode u omjeru 1: 2, pritisnite i zapečate i stavite na 4 ° C, izjednačeni 24 h. Zamrznite se na 18 ° C (0, 15, 30 i 60 dana). Dodajte 0,5%, 1%, 2%(w/w) HPMC da biste zamijenili odgovarajuću kvalitetu škroba, a druge metode pripreme ostaju nepromijenjene. Nakon završetka vremena skladištenja zamrzavanja, izvadite lopov i uravnotežite na 4 ° C 4 sata.
(3) Određivanje temperature želatinizacije i promjene entalpije

4.2.3.5 XRD mjerenje
Odmrznuti uzorci smrznutog škroba sušeni su u pećnici na 40 ° C tokom 48 h, zatim mljeveni i prosijani kroz sito od 100 mreža kako bi se dobili uzorci škroba u prahu. Take a certain amount of the above samples, use D/MAX 2500V type X. The crystal form and relative crystallinity were determined by X-ray diffractometer. The experimental parameters are voltage 40 KV, current 40 mA, using Cu. Ks as X. ray source. At room temperature, the scanning angle range is 30--400, and the scanning rate is 20/min. Relative crystallinity (%) = crystallization peak area/total area x 100%, where the total area is the sum of the background area and the peak integral area [1 62].
4.2.3.6 Određivanje snage bubrenja škroba
Take 0.1 g of the dried, ground and sieved amyloid into a 50 mL centrifuge tube, add 10 mL of distilled water to it, shake it well, let it stand for 0.5 h, and then place it in a 95°C water bath at a constant temperature. Nakon 30 minuta, nakon završetka želatinizacije, izvadite cijev za centrifugu i stavite je u ledenu kupelj 10 minuta za brzo hlađenje. Konačno, centrifugirajte na 5000 o / min 20 minuta i izlijte supernatanta kako biste dobili talog. Swelling Power=precipitation mass/sample mass [163].

All experiments were repeated at least three times unless otherwise specified, and the experimental results were expressed as mean and standard deviation. SPSS statistika 19 korišten je za analizu varijance (Analiza varijance, ANOVA) s razinom značajnosti od 0,05; correlation charts were drawn using Origin 8.0.


According to GB 50093.2010, GB/T 5009.9.2008, GB 50094.2010 (78-s0), the basic components of wheat starch - moisture, amylose/amylopectin and ash content were determined. Rezultati su prikazani u tablici 4. 1.
Dodirnite 4．1 Sadržaj sastojka pšeničnog škroba

4.3.2 Učinci količine dodavanja HPMC -a i smrznuto vrijeme skladištenja na karakteristike želatinizacije pšeničnog škroba
Suspenzija škroba s određenom koncentracijom zagrijava se određenom brzinom grijanja kako bi se želatinizirao škrob. Nakon što se počne želatinizirati, mutna tekućina postupno postaje pasta zbog širenja škroba, a viskoznost se kontinuirano povećava. Subsequently, the starch granules rupture and the viscosity decreases. Kad se pasta ohladi s određenom brzinom hlađenja, pasta će se gel, a vrijednost viskoznosti će se dodatno povećavati. The viscosity value when it is cooled to 50 °C is the final viscosity value (Figure 4.1).
Tablica 4.2 navodi utjecaj nekoliko važnih pokazatelja karakteristika želatinizacije škroba, uključujući vršnu viskoznost želatine, minimalnu viskoznost, konačnu viskoznost, vrijednost propadanja i vrijednost uvažavanja i odražava učinak dodavanja HPMC -a i vremena zamrzavanja na pastu škroba. Učinci kemijskih svojstava. Eksperimentalni rezultati pokazuju da se vršna viskoznost, minimalna viskoznost i konačna viskoznost škroba bez smrznutog skladištenja značajno povećali s povećanjem dodavanja HPMC -a, dok su vrijednost propadanja i vrijednost oporavka značajno smanjeni. Specifically, the peak viscosity gradually increased from 727.66+90.70 CP (without adding HPMC) to 758.51+48.12 CP (adding 0.5% HPMC), 809.754-56.59 CP (adding 1 %HPMC), and 946.64+9.63 CP (adding 2% HPMC); the minimum viscosity was increased from 391.02+18.97 CP (blank not adding) to 454.95+36.90 (adding O .5% HPMC), 485.56+54.0.5 (add 1% HPMC) and 553.03+55.57 CP (add 2% HPMC); the final viscosity is from 794.62.412.84 CP ( Without adding HPMC) increased to 882.24±22.40 CP (adding 0.5% HPMC), 846.04+12.66 CP (adding 1% HPMC) and 910.884-34.57 CP (adding 2 %HPMC); however, the attenuation value gradually decreased from 336.644-71.73 CP (without adding HPMC) to 303.564-11.22 CP (adding 0.5% HPMC), 324.19±2.54 CP (Add
With 1% HPMC) and 393.614-45.94 CP (with 2% HPMC), the retrogradation value decreased from 403.60+6.13 CP (without HPMC) to 427.29+14.50 CP, respectively (0.5% HPMC added), 360.484-41.39 CP (15 HPMC added) and 357.85+21.00 CP (2% HPMC added). This and the addition of hydrocolloids such as xanthan gum and guar gum obtained by Achayuthakan & Suphantharika (2008) and Huang (2009) can increase the gelatinization viscosity of starch while reducing the retrogradation value of starch. This may be mainly because HPMC acts as a kind of hydrophilic colloid, and the addition of HPMC increases the gelatinization peak viscosity due to the hydrophilic group on its side chain which makes it more hydrophilic than starch granules at room temperature. In addition, the temperature range of the thermal gelatinization process (thermogelation process) of HPMC is larger than that of starch (results not shown), so that the addition of HPMC can effectively suppress the drastic decrease in viscosity due to the disintegration of starch granules. Stoga se minimalna viskoznost i konačna viskoznost želatinizacije škroba postupno povećavali s povećanjem sadržaja HPMC.
On the other hand, when the amount of HPMC added was the same, the peak viscosity, minimum viscosity, final viscosity, decay value and retrogradation value of starch gelatinization increased significantly with the extension of freezing storage time. Konkretno, vršna viskoznost suspenzije škroba bez dodavanja HPMC povećala se sa 727,66 ± 90,70 CP (smrznuto skladištenje u trajanju od 0 dana) na 1584,44+68,11 CP (zamrznuti skladištenje u trajanju od 60 dana); Dodavanje 0,5, vršna viskoznost suspenzije škroba s %HPMC povećala se sa 758,514-48,12 CP (zamrzavanje za 0 dana) na 1415,834-45,77 CP (smrzavanje tijekom 60 dana); starch suspension with 1% HPMC added The peak viscosity of the starch liquid increased from 809.754-56.59 CP (freeze storage for 0 days) to 1298.19-±78.13 CP (frozen storage for 60 days); while the starch suspension with 2% HPMC CP added Gelatinization peak viscosity from 946.64 ± 9.63 CP (0 days frozen) increased to 1240.224-94.06 CP (60 days frozen). Istodobno, najniža viskoznost suspenzije škroba bez HPMC-a povećana je sa 391.02-41 8,97 CP (smrzavanje za 0 dana) na 556,77 ± 29,39 CP (zamrzavanje tijekom 60 dana); Dodavanje 0,5 minimalna viskoznost suspenzije škroba s %HPMC porasla je sa 454,954-36,90 CP (zamrzavanje za 0 dana) na 581,934-72,22 CP (zamrzavanje tijekom 60 dana); Suspenzija škroba s 1% HPMC dodala je minimalnu viskoznost tekućine porasla sa 485,564-54,05 CP (smrzavanje za 0 dana) na 625,484-67.17 CP (zamrzavanje tijekom 60 dana); Dok je suspenzija škroba dodala 2% HPMC CP želatinizirana, najniža viskoznost povećala se sa 553,034-55,57 CP (0 dana zamrznuto) na 682,58 ± 20,29 CP (60 dana zamrznuti).

The final viscosity of starch suspension without adding HPMC increased from 794.62 ± 12.84 CP (frozen storage for 0 days) to 1413.15 ± 45.59 CP (frozen storage for 60 days). Vrhunska viskoznost suspenzije škroba povećala se sa 882,24 ± 22,40 CP (smrznuto skladištenja u trajanju od 0 dana) na 1322,86 ± 36,23 CP (zamrznuti skladištenje 60 dana); the peak viscosity of starch suspension added with 1% HPMC The viscosity increased from 846.04 ± 12.66 CP (frozen storage 0 days) to 1291.94 ± 88.57 CP (frozen storage for 60 days); and the gelatinization peak viscosity of starch suspension added with 2% HPMC increased from 91 0.88 ± 34.57 CP
(Frozen storage for 0 days) increased to 1198.09 ± 41.15 CP (frozen storage for 60 days). Correspondingly, the attenuation value of starch suspension without adding HPMC increased from 336.64 ± 71.73 CP (frozen storage for 0 days) to 1027.67 ± 38.72 CP (frozen storage for 60 days); Dodavanje 0,5 vrijednosti prigušivanja suspenzije škroba s %HPMC porasla je sa 303,56 ± 11,22 CP (zamrznuti skladištenje u trajanju od 0 dana) na 833,9 ± 26,45 CP (smrznuto skladištenje u trajanju od 60 dana); starch suspension with 1% HPMC added The attenuation value of the liquid was increased from 324.19 ± 2.54 CP (freezing for 0 days) to 672.71 ± 10.96 CP (freezing for 60 days); dok je dodavanje 2% HPMC ， vrijednost prigušivanja suspenzije škroba povećala se sa 393,61 ± 45,94 CP (zamrzavanje za 0 dana) na 557,64 ± 73,77 CP (zamrzavanje tijekom 60 dana); while the starch suspension without HPMC added The retrogradation value increased from 403.60 ± 6.13 C
P (smrznuto skladištenja 0 dana) do 856,38 ± 16,20 CP (smrznuto skladištenje u trajanju od 60 dana); the retrogradation value of starch suspension added with 0.5% HPMC increased from 427 .29±14.50 CP (frozen storage for 0 days) increased to 740.93±35.99 CP (frozen storage for 60 days); Vrijednost retrogradne suspenzije škroba dodana s 1% HPMC povećala se sa 360,48 ± 41. 39 CP (smrznuto skladištenje u trajanju od 0 dana) porastao je na 666,46 ± 21,40 CP (smrznuto skladištenje u trajanju od 60 dana); while the retrogradation value of starch suspension added with 2% HPMC increased from 357.85 ± 21.00 CP (frozen storage for 60 days). 0 days) increased to 515.51 ± 20.86 CP (60 days frozen).
It can be seen that with the prolongation of freezing storage time, the starch gelatinization characteristics index increased, which is consistent with Tao et a1. F2015) 1. U skladu s eksperimentalnim rezultatima, otkrili su da su s povećanjem broja ciklusa smrzavanja i odmrzavanja, vršna viskoznost, minimalna viskoznost, konačna viskoznost, vrijednost propadanja i vrijednost retrogradne gelatinizacije škroba, sve na različite stupnjeve [166J]. This is mainly because in the process of freezing storage, the amorphous region (Amorphous Region) of starch granules is destroyed by ice crystallization, so that the amylose (the main component) in the amorphous region (non-crystalline region) undergoes phase separation (Phase. separated) phenomenon, and dispersed in the starch suspension, resulting in an increase in the viscosity of starch gelatinization, and an increase in the related attenuation value and retrogradation value. However, the addition of HPMC inhibited the effect of ice crystallization on starch structure. Stoga se vršna viskoznost, minimalna viskoznost, konačna viskoznost, vrijednost propadanja i brzina retrogradnog želatinizacije škroba povećala dodavanjem HPMC -a tijekom zamrznutog skladištenja. increase and decrease sequentially.

Slika 4．1 Zalijepljenja krivulje pšeničnog škroba bez HPMC (a) ili s 2 ％ HPMC①)
4.3.3 Učinci količine dodavanja HPMC -a i smrznuto vrijeme skladištenja na smicanje viskoznosti paste od škroba
Učinak stope smicanja na prividnu viskoznost (smična viskoznost) tekućine ispitivan je testom stalnog protoka, a struktura materijala i svojstva tekućine odražena su u skladu s tim. Tablica 4.3 navodi parametre jednadžbe dobivene nelinearnim ugradnjom, to jest koeficijent konzistentnosti K i karakteristični indeks protoka D, kao i utjecaj količine dodavanja HPMC -a i vremena zamrzavanja na gornjim parametrima K Gate.

Slika 4．2 Thiksotropizam paste od škroba bez HPMC (a) ili s 2 ％ HPMC (b)

Iz tablice 4.3 može se vidjeti da su svi karakteristični indeksi protoka, 2, manji od 1., dakle, škrobna pasta (bilo da se dodaje HPMC ili je li smrznuta ili ne) pripada pseudoplastičnoj tekućini, a svi pokazuju da se pojava stanjivanja (kako se brzina smicanja povećava, shema viskoznosti fluida. In addition, the shear rate scans ranged from 0.1 s, respectively. 1 increased to 100 s ~, and then decreased from 100 sd to O. The rheological curves obtained at 1 sd do not completely overlap, and the fitting results of K, s are also different, so the starch paste is a thixotropic pseudoplastic fluid (whether HPMC is added or whether it is frozen or not). Međutim, u istom vremenu skladištenja zamrzavanja, s povećanjem dodavanja HPMC -a, razlika između odgovarajućih rezultata k n vrijednosti dvaju skeniranja postupno se smanjivala, što ukazuje na to da dodavanje HPMC -a čini strukturu paste od škroba pod stresom smicanja. It remains relatively stable under the action and reduces the "thixotropic ring"
(Thixotropic Loop) area, which is similar to Temsiripong, et a1. (2005) izvijestio je isti zaključak [167]. This may be mainly because HPMC can form intermolecular cross-links with gelatinized starch chains (mainly amylose chains), which "bound" the separation of amylose and amylopectin under the action of shearing force. , so as to maintain the relative stability and uniformity of the structure (Figure 4.2, the curve with shear rate as abscissa and shear stress as ordinate).
On the other hand, for the starch without frozen storage, its K value decreased significantly with the addition of HPMC, from 78.240±1.661 Pa ·sn (without adding HPMC) to 65.240±1.661 Pa ·sn (without adding HPMC), respectively. 683 ± 1,035 PA · SN (dodajte 0,5% MC), 43,122 ± 1,047 PA · SN (dodajte 1% HPMC) i 13,926 ± 0,330Pa · SN (dodajte 2% HPMC), dok je N vrijednost porasla na 0,277 ± 0,0M) 310 ± 0.009 (add 0.5% HPMC), O. 323 ± 0.013 (add 1% HPMC) and O. 43 1 ± 0.0 1 3 (adding 2% HPMC), which is similar to the experimental results of Techawipharat, Suphantharika, & BeMiller (2008) and Turabi, Sumnu, & Sahin (2008), and the increase of n value shows that the addition of HPMC makes the fluid has a tendency to change from pseudoplastic to Newtonian [168'1691]. at the same time, For the starch stored frozen for 60 days, the K, n values showed the same change rule with the increase of HPMC addition.
However, with the prolongation of freezing storage time, the values ​​of K and n increased to different degrees, among which the value of K increased from 78.240 ± 1.661 Pa·sn (unadded, 0 days) to 95.570 ± 1, respectively. 2.421 Pa·sn (no addition, 60 days), increased from 65.683±1.035 Pa ·S n (addition of O. 5% HPMC, 0 days) to 51.384±1.350 Pa ·S n (Add to 0.5% HPMC, 60 days), increased from 43.122±1.047 Pa ·sn (adding 1% HPMC, 0 days) to 56.538±1.378 Pa ·sn (adding 1% HPMC, 60 days) ), and increased from 13.926 ± 0.330 Pa ·sn (adding 2% HPMC, 0 days) to 16.064 ± 0.465 Pa ·sn (adding 2% HPMC, 60 days); 0.277 ± 0.011 (without adding HPMC, 0 days) rose to O. 334±0.014 (no addition, 60 days), increased from 0.310±0.009 (0.5% HPMC added, 0 day) to 0.336±0.014 (0.5% HPMC added, 60 days), from 0.323 ± 0.013 (add 1% HPMC, 0 days) to 0.340 ± 0.013 (add 1% HPMC, 60 days), and from 0.431 ± 0.013 (add 1% HPMC, 60 days) 2% HPMC, 0 days) to 0.404+0.020 (add 2% HPMC, 60 days). By comparison, it can be found that with the increase of the addition amount of HPMC, the change rate of K and Knife value decreases successively, which shows that the addition of HPMC can make the starch paste stable under the action of shearing force, which is consistent with the measurement results of starch gelatinization characteristics. dosljedan.
4.3.4 Učinci količine dodavanja HPMC -a i smrznuto vrijeme skladištenja na dinamičnu viskoelastičnost paste s škrobom
Pometanje dinamičke frekvencije može učinkovito odražavati viskoelastičnost materijala, a za pastu od škroba to se može koristiti za karakterizaciju njegove čvrstoće gela (čvrstoća gela). Na slici 4.3 prikazane su promjene modula za pohranu/elastični modul (G ') i modul gubitka/modul viskoznosti (G ") škrobnog gela u uvjetima različitog dodavanja HPMC -a i vremena zamrzavanja.

Slika 4．3 Učinak dodavanja HPMC -a i smrznuto skladištenja na elastično i viskozni modul paste od škroba

The starch gelatinization process is accompanied by the disintegration of starch granules, the disappearance of the crystalline region, and the hydrogen bonding between starch chains and moisture, the starch gelatinized to form a heat-induced (Heat. induced) gel with a certain gel strength. Kao što je prikazano na slici 4.3, za škrob bez zamrznutog skladištenja, s povećanjem dodavanja HPMC -a, G 'škroba značajno se smanjio, dok G "nije imao značajnu razliku, a tan 6 se povećao (tekući. 1ike), što pokazuje da je tijekom procesa gelatinizacije HPMC u interakciji s škrtima, a pričvršćivanje hPMC -a, a dodatak HPMC -u, a dodatak HPMC -u. U isto vrijeme, Chaisawang & Suphantharika (2005) su otkrili da je, dodajući guransku gumu i ksantansku gumu tapioci škrob, pasti s škrobom također se smanjio [170]. amorphous region of starch granules is separated to form damaged starch (Damaged Starch), which reduces the degree of intermolecular cross-linking after starch gelatinization and the degree of cross-linking after cross-linking. Stability and compactness, and the physical extrusion of ice crystals makes the arrangement of "micelles" (microcrystalline structures, mainly composed of amylopectin) in the starch crystallization area more compact, increasing the relative crystallinity of starch, and at the same time , resulting in insufficient combination of molecular chain and water after starch gelatinization, low extension of molecular chain (molecular chain mobility), and finally caused the gel strength of starch to decline. However, with the increase of HPMC addition, the decreasing trend of G' was suppressed, and this effect was positively correlated with the addition of HPMC. This indicated that the addition of HPMC could effectively inhibit the effect of ice crystals on the structure and properties of starch under frozen storage conditions.

The swelling ratio of starch can reflect the size of starch gelatinization and water swelling, and the stability of starch paste under centrifugal conditions. As shown in Figure 4.4, for starch without frozen storage, with the increase of HPMC addition, the swelling force of starch increased from 8.969+0.099 (without adding HPMC) to 9.282- -L0.069 (adding 2% HPMC), which shows that the addition of HPMC increases the swelling water absorption and makes starch more stable after gelatinization, which is consistent with the conclusion karakteristike želatinizacije škroba. Međutim, s produljenjem vremena zamrznutog skladištenja, moć oteklina škroba smanjila se. Compared with 0 days of frozen storage, the swelling power of starch decreased from 8.969-a:0.099 to 7.057+0 after frozen storage for 60 days, respectively. .007 (no HPMC added), reduced from 9.007+0.147 to 7.269-4-0.038 (with O.5% HPMC added), reduced from 9.284+0.157 to 7.777 +0.014 (adding 1% HPMC), reduced from 9.282+0.069 to 8.064+0.004 (adding 2% HPMC). The results showed that the starch granules were damaged after freezing storage, resulting in the precipitation of part of the soluble starch and centrifugation. Stoga se topljivost škroba povećavala i snaga oteklina se smanjila. In addition, after freezing storage, starch gelatinized starch paste, its stability and water holding capacity decreased, and the combined action of the two reduced the swelling power of starch [1711]. On the other hand, with the increase of HPMC addition, the decline of starch swelling power gradually decreased, indicating that HPMC can reduce the amount of damaged starch formed during freezing storage and inhibit the degree of starch granule damage.

Slika 4．4 Utjecaj dodavanja HPMC -a i smrznutog pohrane na oteklinu snagu škroba
4.3.6 Učinci količine dodavanja HPMC -a i smrznuto vrijeme skladištenja na termodinamička svojstva škroba
Želatinizacija škroba je endotermički kemijski termodinamički postupak. Therefore, DSC is often used to determine the onset temperature (Dead), peak temperature (To), end temperature (T p), and gelatinization enthalpy of starch gelatinization. (Tc). Table 4.4 shows the DSC curves of starch gelatinization with 2% and without HPMC added for different freezing storage times.




Kao što je prikazano u tablici 4.4, za svježi amiloid, s povećanjem dodavanja HPMC -a, škrob L nema značajnu razliku, ali se značajno povećava, sa 77,530 ± 0,028 (bez dodavanja HPMC -a) na 78,010 ± 0,042 (dodavanje 0,5% HPMC), 78,507 ± 0,051 (Add 1,05 ± 2% HPMC), ali 4H je značajno smanjenje, s 9,450 ± 0,095 (bez dodavanja HPMC) na 8,53 ± 0,030 (dodavanje 0,5% HPMC), 8,242A: 0,080 (dodavanje 1% HPMC) i 7 .736 ± 0,066 (dodajte 2% HPMC (dodajte 2% HPMC (dodajte 2% HPMC (dodajte 2% HPMC) To je slično Zhou, et A1. (2008) otkrili su da je dodavanje hidrofilnog koloida smanjilo entalpiju škroba želatinizacije i povećalo vršnu temperaturu škroba želatinizacije [172]. To je uglavnom zato što HPMC ima bolju hidrofilnost i lakše je kombinirati s vodom od škroba. Istodobno, zbog velikog temperaturnog raspona termički ubrzanog procesa geliranja HPMC -a, dodavanje HPMC povećava vršnu temperaturu želatinizacije škroba, dok se entalpija želatinizacije smanjuje.
On the other hand, starch gelatinization To, T p, Tc, △T and △Hall increased with the extension of freezing time. Konkretno, dodani škrob želatinizacija s 1% ili 2% HPMC nije imalo značajne razlike nakon zamrzavanja 60 dana, dok je škrob bez ili sa 0,5% HPMC dodan iz 68,955 ± 0,01 7 (smrznuto skladištenja za 0 dana) porasla na 72,340 ± 0,093 (Fromozen, i od 60 dana), i od 6,093. 71.613 ± 0.085 (frozen storage for 0 days) 60 days); after 60 days of frozen storage, the growth rate of starch gelatinization decreased with the increase of HPMC addition, such as starch without HPMC added from 77.530 ± 0.028 (frozen storage for 0 days) to 81.028. 408 ± 0.021 (frozen storage for 60 days), while the starch added with 2% HPMC increased from 78.606 ± 0.034 (frozen storage for 0 days) to 80.017 ± 0.032 (frozen storage for 60 days). days); in addition, ΔH also showed the same change rule, which increased from 9.450 ± 0.095 (no addition, 0 days) to 12.730 ± 0.070 (no addition, 60 days), respectively, from 8.450 ± 0.095 (no addition, 0 days) to 12.730 ± 0.070 (no addition, 60 days), respectively. 531 ± 0,030 (dodajte 0,5%, 0 dana) na 11,643 ± 0,019 (dodajte 0,5%, 60 dana), od 8,242 ± 0,080 (dodajte 1%, 0 dana) do 10,509 ± 0,029 (dodajte 1%± 60 dana), a sa 7,736 ± O.%, 2, 0,36 (2, dodatak 0,736 ± O. days). Glavni razlozi gore navedenih promjena u termodinamičkim svojstvima želatinizacije škroba tijekom procesa zamrznutog skladištenja su stvaranje oštećenog škroba, koji uništava amorfnu regiju (amorfnu regiju) i povećava kristalnost kristalne regije. The coexistence of the two increases the relative crystallinity of starch, which in turn leads to an increase in thermodynamic indexes such as starch gelatinization peak temperature and gelatinization enthalpy. However, through comparison, it can be found that under the same freezing storage time, with the increase of HPMC addition, the increase of starch gelatinization To, T p, Tc, ΔT and ΔH gradually decreases. It can be seen that the addition of HPMC can effectively maintain the relative stability of the starch crystal structure, thereby inhibiting the increase of the thermodynamic properties of starch gelatinization.
4.3.7 Učinci I-IPMC dodavanja i vremena zamrzavanja na relativnu kristalnost škroba

Slika 4.6. Kao što je prikazano u A, položaji vrhova kristalizacije škroba nalaze se na 170, 180, 190 i 230, i nema značajnih promjena u vršnim položajima bez obzira na to jesu li tretirani zamrzavanjem ili dodavanjem HPMC -a. To pokazuje da, kao svojstveno svojstvo kristalizacije pšeničnog škroba, kristalni oblik ostaje stabilan.
However, with the prolongation of freezing storage time, the relative crystallinity of starch increased from 20.40 + 0.14 (without HPMC, 0 days) to 36.50 ± 0.42 (without HPMC, frozen storage, respectively). 60 days), and increased from 25.75 + 0.21 (2% HPMC added, 0 days) to 32.70 ± 0.14 (2% HPMC added, 60 days) (Figure 4.6.B), this and Tao, et a1. (2016), pravila promjene rezultata mjerenja su konzistentna [173-174]. The increase in relative crystallinity is mainly caused by the destruction of the amorphous region and the increase in the crystallinity of the crystalline region. In addition, consistent with the conclusion of the changes in the thermodynamic properties of starch gelatinization, the addition of HPMC reduced the degree of relative crystallinity increase, which indicated that during the freezing process, HPMC could effectively inhibit the structural damage of starch by ice crystals and maintain the Its structure and properties are relatively stable.


Note: A is x. Rendgenski difrakcijski uzorak; B is the relative crystallinity result of starch;
4.4 Sažetak poglavlja
Škrob je najzastupljenija suha tvar u tijestu, koja nakon želatine dodaje jedinstvene kvalitete (specifična volumena, tekstura, senzorni, okus itd.) U proizvodu tijesta. Since the change of starch structure will affect its gelatinization characteristics, which will also affect the quality of flour products, in this experiment, the gelatinization characteristics, flowability and flowability of starch after frozen storage were investigated by examining starch suspensions with different contents of HPMC added. Promjene u reološkim svojstvima, termodinamičkim svojstvima i kristalnoj strukturi korištene su za procjenu zaštitnog učinka dodavanja HPMC -a na strukturu granula škroba i srodnih svojstava. The experimental results showed that after 60 days of frozen storage, the starch gelatinization characteristics (peak viscosity, minimum viscosity, final viscosity, decay value and retrogradation value) all increased due to the significant increase in the relative crystallinity of starch and the increase in the content of damaged starch. The gelatinization enthalpy increased, while the gel strength of starch paste decreased significantly; Međutim, posebno suspenzija škroba dodana s 2% HPMC -om, relativna kristalnost povećava stupanj oštećenja i oštećenja škroba nakon zamrzavanja bila je niža od onih u kontrolnoj skupini, dakle, dodavanje HPMC -a smanjuje stupanj promjena u karakteristikama želatinizacije, želatinizacijsku entalpiju i snagu gela, što ukazuje na to da dodavanje HPMC -a u skladu s HPMC -om.

5.1 Uvod
Yeast is a unicellular eukaryotic microorganism, its cell structure includes cell wall, cell membrane, mitochondria, etc., and its nutritional type is a facultative anaerobic microorganism. U anaerobnim uvjetima, proizvodi alkohol i energiju, dok se u aerobnim uvjetima metabolizira za proizvodnju ugljičnog dioksida, vode i energije.
Yeast has a wide range of applications in fermented flour products (sourdough is obtained by natural fermentation, mainly lactic acid bacteria), it can use the hydrolyzed product of starch in the dough - glucose or maltose as a carbon source, under aerobic conditions, using Substances produce carbon dioxide and water after respiration. Proizvedeni ugljični dioksid tijesto može učiniti labavim, poroznim i glomaznim. At the same time, the fermentation of yeast and its role as an edible strain can not only improve the nutritional value of the product, but also significantly improve the flavor characteristics of the product. Therefore, the survival rate and fermentation activity of yeast have an important impact on the quality of the final product (specific volume, texture, and flavor, etc.) [175].
U slučaju smrznutog skladištenja, kvas će utjecati na stres okoliša i utjecati na njegovu održivost. When the freezing rate is too high, the water in the system will rapidly crystallize and increase the external osmotic pressure of the yeast, thereby causing the cells to lose water; when the freezing rate is too high. Ako je prenisko, ledeni kristali bit će preveliki i kvasac će biti stisnut i stanična stijena će biti oštećena; both will reduce the survival rate of the yeast and its fermentation activity. In addition, many studies have found that after the yeast cells are ruptured due to freezing, they will release a reducing substance-reduced glutathione, which in turn reduces the disulfide bond to a sulfhydryl group, which will eventually destroy the network structure of gluten protein, resulting in a decrease in the quality of pasta products [176-177].
Because HPMC has strong water retention and water holding capacity, adding it to the dough system can inhibit the formation and growth of ice crystals. U ovom su eksperimentu u tijesto dodane različite količine HPMC -a, a nakon određenog vremenskog razdoblja nakon smrznutog skladištenja, količina kvasca, fermentacijske aktivnosti i sadržaja glutationa u jedinici mase tijesta utvrđena je kako bi se procijenio zaštitni učinak HPMC -a na kvascima u uvjetima zamrzavanja.
5.2 Materijali i metode
5.2.1 Eksperimentalni materijali i instrumenti

Anđeo aktivni suhi kvasac
Bps. 500Cl okvir stalne temperature i vlage
3m solidna filmska kolonija brzog broja test komad
Sp. Model 754 UV spektrofotometar

KDC. 160h brze hladnjake centrifuge
ZWY-240 Inkubator konstantne temperature
BDS. 200 obrnuti biološki mikroskop

Proizvođač
Angel Quast Co., Ltd.


Shanghai Spectrum Scientific Instrument Co., Ltd.
JIANGSU TONGJING PROIZVODNJA OPREMA CO., LTD.

SHANGHAI ZHICHENG Analitički instrument Manufacturing Co., Ltd.
Chongqing Auto Optical Instrument Co., Ltd.
5.2.2 Eksperimentalna metoda

Weigh 3 g of active dry yeast, add it to a sterilized 50 mL centrifuge tube under aseptic conditions, and then add 27 mL of 9% (w/V) sterile saline to it, shake it up, and prepare 10% (w/w) yeast broth. Then, quickly move to. Store in a refrigerator at 18°C. Nakon 15 d, 30 d i 60 d smrznute skladištenja, uzorci su izvađeni za testiranje. Dodajte 0,5%, 1%, 2%HPMC (w/w) kako biste zamijenili odgovarajući postotak aktivne mase suhog kvasca. In particular, after the HPMC is weighed, it must be irradiated under an ultraviolet lamp for 30 minutes for sterilization and disinfection.
5.2.2.2. Visina provjere tijesta
See Meziani, et a1. (2012) eksperimentalna metoda [17 citirana, s malim modifikacijama. Izdvojite 5 g smrznutog tijesta u kolorimetrijsku cijev od 50 ml, pritisnite tijesto na jednoliku visinu od 1,5 cm na dnu cijevi, a zatim ga stavite uspravno u konstantnu temperaturu i kutiju vlage i inkubirajte 1 sat na 30 ° C i 85% RH, nakon što ga izvadite, odmjerite dva nasuprot. For samples with uneven upper ends after proofing, select 3 or 4 points at equal intervals to measure their corresponding heights (for example, each 900), and the measured height values were averaged. Svaki je uzorak paralelan tri puta.
5.2.2.3. CFU (jedinice koje formiraju koloniju)
Izvažite 1 g tijesta, dodajte je u epruvetu s 9 ml sterilne normalne fiziološke otopine prema zahtjevima aseptičke operacije, u potpunosti ga protresite, zabilježite gradijent koncentracije kao 101, a zatim ga razrijedite u niz gradijenata koncentracije do 10'1. Draw 1 mL of dilution from each of the above tubes, add it to the center of the 3M yeast rapid count test piece (with strain selectivity), and place the above test piece in a 25°C incubator according to the operating requirements and culture conditions specified by 3M. 5 d, take out after the end of the culture, first observe the colony morphology to determine whether it conforms to the colony characteristics of yeast, and then count and microscopically examine [179]. Each sample was repeated three times.
5.2.2.4. Određivanje sadržaja glutationa
The alloxan method was used to determine the glutathione content. The principle is that the reaction product of glutathione and alloxan has an absorption peak at 305 nl. Specific determination method: pipette 5 mL of yeast solution into a 10 mL centrifuge tube, then centrifuge at 3000 rpm for 10 min, take 1 mL of supernatant into a 10 mL centrifuge tube, add 1 mL of 0.1 mol/mL to the tube L alloxan solution, mixed thoroughly, then add 0.2 M PBS (pH 7.5) and 1 mL of 0.1 M, NaOH solution to it, mix well, let stand for 6 min, and immediately add 1 M, NaOH The solution was 1 mL, and the absorbance at 305 nm was measured with a UV spectrophotometer after thorough mixing. The glutathione content was calculated from the standard curve. Svaki je uzorak paralelan tri puta.

Eksperimentalni rezultati prikazani su kao odstupanja od 4 standarda srednje vrijednosti, a svaki je eksperiment ponovljen najmanje tri puta. Analysis of variance was performed using SPSS, and the significance level was 0.05. Use Origin to draw graphs.

5.3.1 Utjecaj količine dodavanja HPMC -a i zamrznuto vrijeme skladištenja na visinu provjere tijesta
Na visinu tijesta često utječe kombinirani učinak proizvodnje plina fermentacije kvasca i čvrstoće strukture mreže tijesta. Među njima će aktivnost fermentacije kvasca izravno utjecati na njegovu sposobnost fermentacije i proizvodnje plina, a količina proizvodnje plina kvasca određuje kvalitetu fermentiranih proizvoda od brašna, uključujući određenu volumen i teksturu. The fermentation activity of yeast is mainly affected by external factors (such as changes in nutrients such as carbon and nitrogen sources, temperature, pH, etc.) and internal factors (growth cycle, activity of metabolic enzyme systems, etc.).

Slika 5．1 Utjecaj dodavanja HPMC -a i smrznutog skladištenja na visinu dokazivanja tijesta
As shown in Figure 5.1, when frozen for 0 days, with the increase in the amount of HPMC added, the proofing height of the dough increased from 4.234-0.11 cm to 4.274 cm without adding HPMC. -0.12 cm (0.5% HPMC added), 4.314-0.19 cm (1% HPMC added), and 4.594-0.17 cm (2% HPMC added) This may be mainly due to HPMC Addition changes the properties of the dough network structure (see Chapter 2). However, after being frozen for 60 days, the proofing height of the dough decreased to varying degrees. Specifically, the proofing height of the dough without HPMC was reduced from 4.234-0.11 cm (freezing for 0 days) to 3 .18+0.15 cm (frozen storage for 60 days); Tijesto dodano s 0,5% HPMC smanjeno je s 4,27+0,12 cm (smrznuto skladištenja za 0 dana) na 3,424-0,22 cm (smrznuto skladištenja za 0 dana). 60 days); Tijesto je dodano s 1% HPMC smanjilo se sa 4,314-0,19 cm (smrznuto skladištenja za 0 dana) na 3,774-0,12 cm (smrznuto skladištenja 60 dana); Dok je tijesto dodano s 2% HPMC -a probudilo se. Visina kose je smanjena sa 4,594-0,17 cm (smrznuto skladištenja u trajanju od 0 dana) na 4,09- ± 0,16 cm (smrznuto skladištenje 60 dana). It can be seen that with the increase of the addition amount of HPMC, the degree of decrease in the proofing height of the dough gradually decreases. This shows that under the condition of frozen storage, HPMC can not only maintain the relative stability of the dough network structure, but also better protect the survival rate of yeast and its fermentation gas production activity, thereby reducing the quality deterioration of fermented noodles.
5.3.2 Utjecaj I-IPMC dodavanja i vremena zamrzavanja na stopu preživljavanja kvasca
In the case of frozen storage, since the frozen water in the dough system is converted into ice crystals, the osmotic pressure outside the yeast cells is increased, so that the protoplasts and cell structures of the yeast are under a certain degree of stress. Kad se temperatura dugo spusti ili drži na niskoj temperaturi, u stanicama kvasca pojavit će se mala količina kristala leda, što će dovesti do uništavanja stanične strukture kvasca, ekstravazacije stanične tekućine, poput oslobađanja reducirajuće tvari - glutationne ili čak potpune smrti; at the same time, the yeast Under environmental stress, its own metabolic activity will be reduced, and some spores will be produced, which will reduce the fermentation gas production activity of yeast.

Slika 5．2 Utjecaj dodavanja HPMC -a i smrznuto skladištenja na stopu preživljavanja kvasca
Na slici 5.2 može se vidjeti da nema značajne razlike u broju kolonija kvasca u uzorcima s različitim sadržajem HPMC -a dodanih bez liječenja zamrzavanja. To je slično rezultatu koji su utvrdili Heitmann, Zannini, & Arendt (2015) [180]. Međutim, nakon 60 dana smrzavanja, broj kolonija kvasca značajno se smanjio, sa 3.08x106 CFU na 1,76x106 CFU (bez dodavanja HPMC); od 3.04x106 CFU do 193x106 CFU (dodavanje 0,5% HPMC); smanjeno sa 3.12x106 CFU na 2.14x106 CFU (dodano 1% HPMC); smanjeno sa 3.02x106 CFU na 2,55x106 CFU (dodano 2% HPMC). Za usporedbu, može se utvrditi da je stres zamrzavajućeg okoliša za skladištenje doveo do smanjenja broja kolonije kvasca, ali s povećanjem dodavanja HPMC -a, stupanj smanjenja broja kolonije smanjio se zauzvrat. This indicates that HPMC can better protect yeast under freezing conditions. Mehanizam zaštite može biti isti kao i glicerola, obično korištenog antifriza naprezanja, uglavnom inhibiranjem stvaranja i rasta kristala leda i smanjenjem naprezanja okoliša niske temperature na kvasac. Slika 5.3 je fotomikrograf snimljen iz ispitnog komada brzog brojanja kvasca nakon pripreme i mikroskopskog pregleda, koji je u skladu s vanjskom morfologijom kvasca.

Slika 5．3 Mikrografija kvasca
5.3.3 Učinci dodavanja HPMC -a i vrijeme zamrzavanja na sadržaj glutationa u tijestu
Glutathione is a tripeptide compound composed of glutamic acid, cysteine and glycine, and has two types: reduced and oxidized. Kad se struktura stanice kvasca uništi i umrla, propusnost stanica se povećava, a unutarćelijski glutation se oslobađa na vanjsku stranu stanice i ona je reduktivna. It is particularly worth noting that reduced glutathione will reduce the disulfide bonds (-SS-) formed by the cross-linking of gluten proteins, breaking them to form free sulfhydryl groups (.SH), which in turn affects the dough network structure. stability and integrity, and ultimately lead to the deterioration of the quality of fermented flour products. Obično, pod okolišnim naponom (poput niske temperature, visoke temperature, visokog osmotskog tlaka itd.), Kvasac će smanjiti vlastitu metaboličku aktivnost i povećati otpornost na stres ili istovremeno proizvoditi spore. When the environmental conditions are suitable for its growth and reproduction again, then restore the metabolism and proliferation vitality. Međutim, neki kvasaci s lošom otpornošću na stres ili snažnom metaboličkom aktivnošću i dalje će umrijeti ako se dugo drže u zamrznutom skladišnom okruženju.


Kao što je prikazano na slici 5.4, sadržaj glutationa povećao se bez obzira je li HPMC dodan ili ne, i nije bilo značajne razlike između različitih količina dodavanja. To može biti zato što neki aktivni suhi kvasac koji se koristi za izradu tijesta ima lošu otpornost na stres i toleranciju. Under the condition of low temperature freezing, the cells die, and then glutathione is released, which is only related to the characteristics of the yeast itself. It is related to the external environment, but has nothing to do with the amount of HPMC added. Therefore, the content of glutathione increased within 15 days of freezing and there was no significant difference between the two. However, with the further extension of the freezing time, the increase of glutathione content decreased with the increase of HPMC addition, and the glutathione content of the bacterial solution without HPMC was increased from 2.329a: 0.040mg/ g (frozen storage for 0 days) increased to 3.8514-0.051 mg/g (frozen storage for 60 days); Dok je tekućina kvasca dodala 2% HPMC, njegov sadržaj glutationa povećao se sa 2,307+0 .058 mg/g (smrznuto skladištenja u trajanju od 0 dana) porastao je na 3,351+0,051 mg/g (smrznuto skladištenje u trajanju od 60 dana). To je nadalje ukazivalo da HPMC može bolje zaštititi stanice kvasca i smanjiti smrt kvasca, smanjujući na taj način sadržaj glutationa koji se oslobađa na vanjsku stranu stanice. To je uglavnom zato što HPMC može smanjiti broj kristala leda, čime se učinkovito smanjuje stres kristala leda na kvas i inhibira povećanje izvanstaničnog oslobađanja glutationa.