阅读说明：本技术 一种冷冻面团改良剂及其制备方法和应用 (Frozen dough improver and preparation method and application thereof ) 是由 薛峰 张其乐 秦琳茜 谢宇然 王身艳 刘新页 于 2021-06-29 设计创作，主要内容包括：本发明公开一种冷冻面团改良剂,所述冷冻面团改良剂为麦谷蛋白和类化合物的共价复合物或非共价复合物。发明通过制备麦谷蛋白-多酚复合物,特别是将儿茶素、姜黄素以及原花青素这三种多酚与麦谷蛋白进行共价交联作为冷冻面团改良剂,提升了冷冻面团的强度,同时改善冷冻面团的粘弹特性、恢复能力和抗冻性能,同时也可以提高面筋网络结构的抗冻性能,从而阻碍冷冻面团劣变现象的发生,增加由冷冻面团制备的冷冻面包的比容和降低冷冻面团面包的硬度。(The invention discloses a frozen dough improver which is a covalent compound or a non-covalent compound of glutenin and a compound. According to the preparation method, the glutenin-polyphenol compound is prepared, and particularly, three polyphenols, namely catechin, curcumin and procyanidine, and glutenin are subjected to covalent crosslinking to be used as a frozen dough modifier, so that the strength of the frozen dough is improved, the viscoelastic property, the recovery capability and the freezing resistance of the frozen dough are improved, and the freezing resistance of a gluten network structure can be improved, so that the deterioration phenomenon of the frozen dough is prevented, the specific volume of the frozen bread prepared from the frozen dough is increased, and the hardness of the frozen dough bread is reduced.)

1. A frozen dough conditioner, characterized in that said frozen dough conditioner is a covalent or non-covalent complex of glutenin and polyphenols.

2. Frozen dough conditioner according to claim 1, wherein the mass ratio of glutenin and polyphenols is 1: 0.01-1.

3. Frozen dough conditioner according to claim 1, wherein the polyphenolic compound is a polyphenol or a plant polyphenol extract.

4. The frozen dough improver of claim 1, wherein the polyphenolic compound is any one or more of procyanidins, catechins, curcumin, cyanidin glucoside, cyanidin galactoside, luteolin, myricitrin, chlorogenic acid, grape seed polyphenol extract, pomegranate rind polyphenol extract, grape rind polyphenol extract, blueberry polyphenol extract, tea polyphenols, gallic acid.

5. A process for the preparation of a frozen dough conditioner according to any one of claims 1 to 4, characterized in that the covalent complex is prepared by ultrasonic free radical preparation, alkaline or enzymatic method and the non-covalent complex is prepared by direct mixing.

6. The method according to claim 5, wherein the ultrasonic free radical preparation is prepared by dissolving the formula amount of glutenin solution and polyphenol or polyphenol extract in water, adjusting pH to 7.5-12.0, high speed shearing to dissolve thoroughly and homogenize, then ultrasonic treating, adjusting pH to 6.5-7.5, dialyzing, and freeze-drying.

7. The method as claimed in claim 6, wherein the ultrasonic treatment is intermittent ultrasonic treatment, and the ultrasonic treatment is repeated for 5-40min at 10-80kHz at 800W for 2s and 2s for 5-40 s.

8. The process according to claim 5, wherein the alkaline process comprises dissolving the formulated amount of glutenin solution and polyphenol or polyphenol extract in water, adjusting pH to 7.5-12.0, stirring in the dark for 12-48h, adjusting pH to 6.5-7.5, dialyzing for 12-48h, and freeze-drying.

9. The process according to claim 5, wherein the enzymatic method comprises dissolving the formula amounts of glutenin solution and polyphenol or polyphenol extract in water, adding laccase or polyphenol oxidase, reacting at 25-45 deg.C under stirring for 6-24h, dialyzing for 12-48h, and freeze-drying.

10. Use of a frozen dough conditioner according to claim 1 for improving the viscoelastic and anti-freeze properties of frozen dough and frozen dough products, wherein the frozen dough conditioner is added to the preparation of the frozen dough or frozen dough product in the range of 5 to 15wt% of the total formulation.

Technical Field

The invention belongs to the field of food processing, and particularly relates to a frozen dough improver as well as a preparation method and application thereof.

Background

The frozen dough is a commercial semi-finished product formed by quickly freezing the tanned dough, and a finished product is produced by processes of unfreezing, curing and the like when the frozen dough is used. The frozen dough technology is a new grain and oil processing technology developed in the 20 th century, and solves the problems of short shelf life and easy deterioration of the traditional flour products. However, during the freezing process of the dough, due to the change of ice crystal volume, water migration and protein denaturation, the disaggregation phenomenon of the gluten protein network structure occurs, and finally the product quality is deteriorated. The research on the improvement of the quality of the frozen dough by polyphenol is carried out on the basis of the quality deterioration mechanism of wheat gluten protein in the frozen dough.

In the research of gluten protein degradation of frozen dough, the present finds that the depolymerization of glutenin is the main cause of gluten protein degradation in the freezing storage process. Glutenin is a large aggregate consisting of many peptide chains linked by intermolecular disulfide bonds, and its composition, content and molecular weight distribution directly affect the processing quality of flour, and thus it is desired to improve dough performance by changing the properties of glutenin.

Disclosure of Invention

The purpose of the invention is as follows: in order to solve the technical problems in the prior art, the invention provides a frozen dough modifier, which prevents the occurrence of the deterioration phenomenon of the frozen dough by improving the anti-freezing performance of glutenin.

The technical scheme is as follows: in order to achieve the above technical object, the present invention provides a frozen dough conditioner, which is a covalent complex or a non-covalent complex of glutenin (preferably, the purity of the glutenin is 85% or more) and a polyphenol compound.

Wherein the mass ratio of the glutenin to the polyphenol compound is 1: 0.01-1. Preferably, the mass ratio of glutenin to polyphenol is 1: 0.02.

Specifically, the polyphenol compound is polyphenol or plant polyphenol extract.

More specifically, the polyphenol or polyphenol extract is a combination of one or more of procyanidine, catechol, curcumin, cyanidin glucoside, cyanidin galactoside, luteolin, myricitrin, chlorogenic acid, grape seed polyphenol extract, pomegranate peel polyphenol extract, grape peel polyphenol extract, blueberry polyphenol extract, tea polyphenol and gallic acid, preferably, the polyphenol is procyanidine, catechol or curcumin.

The invention further provides a preparation method of the frozen dough improver, and specifically, the covalent compound is prepared by an ultrasonic free radical preparation method, an alkaline method or an enzymatic method, and the non-covalent compound is prepared by direct mixing.

Wherein, the ultrasonic free radical preparation method comprises dissolving glutenin solution and polyphenol or polyphenol extract in water, adjusting pH to 7.5-12.0, preferably 9, sufficiently dissolving and homogenizing with high speed shearing (preferably 5000-.

Wherein the ultrasonic treatment is intermittent ultrasonic treatment, the ultrasonic treatment is repeated for 5-40min under the conditions of 100-800W and 10-80kHz, working for 2s and stopping for 2 s. Preferably, at 400W, 20kHz, 2s working-2 s stop and sonication is repeated for 20 min.

The alkaline method comprises dissolving glutenin solution and polyphenol or polyphenol extract in water, adjusting pH to 7.5-12.0, stirring in dark for 12-48 hr, adjusting pH to 6.5-7.5, dialyzing for 12-48 hr, and freeze drying. Preferably, the pH is adjusted to 9.0, stirred for 24h in the absence of light, adjusted to pH 7.0, and then dialyzed for 24h and freeze-dried.

The enzyme method comprises dissolving glutenin solution and polyphenol or polyphenol extract in water, adding laccase or polyphenol oxidase, stirring at 25-45 deg.C for 6-24 hr, dialyzing for 12-48 hr, and freeze drying. Preferably, the reaction is stirred at 30 ℃ for 18h, then dialyzed for 24h, and freeze-dried.

The glutenin-polyphenol non-covalent compound is prepared by dissolving glutenin solution and polyphenol or polyphenol extract in water, dissolving thoroughly, homogenizing, and freeze drying.

The invention further provides the application of the frozen dough improver in improving the viscoelastic property and the anti-freezing property of the frozen dough and the frozen dough product, and particularly, the frozen dough improver is added into the preparation process of the frozen dough during application.

Preferably, the modifier is added in the range of 5 to 15wt% of the overall formulation.

Has the advantages that: according to the preparation method, the glutenin-polyphenol compound is prepared, and particularly, three polyphenols, namely catechin, curcumin and procyanidine, and glutenin are subjected to covalent crosslinking to be used as a frozen dough modifier, so that the strength of the frozen dough is improved, the viscoelastic property, the recovery capability and the freezing resistance of the frozen dough are improved, and the freezing resistance of a gluten network structure can be improved, so that the deterioration phenomenon of the frozen dough is prevented, the specific volume of the frozen bread prepared from the frozen dough is increased, and the hardness of the frozen dough bread is reduced.

Drawings

FIG. 1 shows the effect of polyphenol modification on the content of free amino groups (a) and free thiol groups (b) in glutenin;

FIG. 2 shows the effect of polyphenol modification on the surface hydrophobicity (a) and the endogenous fluorescence spectrum (b) of glutenin;

FIG. 3 is a graph showing the effect of polyphenol modification on glutenin particle size (a) and turbidity (b);

FIG. 4 the effect of glutenin-polyphenol complexes on the complex modulus (a), creep recovery capacity (b) and firmness (c) of frozen dough;

FIG. 5 is a graph of the effect of glutenin-polyphenol complexes on the microstructure of frozen dough;

FIG. 6 is a graph of the effect of glutenin-polyphenol complexes on the specific volume and firmness of frozen dough bread;

FIG. 7 is a graph of the effect of different crosslinking patterns of glutenin-curcumin covalent complexes on frozen dough specific volume and hardness.

Detailed Description

The present invention will be described in further detail with reference to specific examples, which will help understanding the present invention, but the scope of the present invention is not limited to the following examples. In the following examples, glutenin was purchased from Shanghai-derived leaf Biotech Co., Ltd at a purity of 85% or more.

Example 1 preparation of glutenin-polyphenol non-covalent complexes.

Preparing glutenin solution with concentration of 2g, adding polyphenol (procyanidin, catechol, and curcumin) 0.04g into 100mL water, dissolving thoroughly, homogenizing, freeze drying, and refrigerating at 4 deg.C.

Example 2 preparation of glutenin-polyphenol covalent complexes.

Glutenin-polyphenol covalent complexes were prepared by three methods:

(1) the ultrasonic free radical preparation method comprises the following steps: preparing 2g glutenin solution, adding 0.04g polyphenol (procyanidin, catechol, and curcumin) into 100mL water, adjusting pH to 9.0, shearing at high speed for 2min (23000 r/min), dissolving thoroughly, homogenizing, performing ultrasonic treatment (400W, 20kHz, 2s work, 2s stop, ultrasonic treatment for 20min), adjusting pH to 7.0, dialyzing for 24h, freeze-drying, and refrigerating at 4 deg.C.

(2) An alkaline method: preparing 2g glutenin solution, adding 0.04g polyphenol (procyanidin, catechol, and curcumin) into 100mL water, adjusting pH to 9.0, stirring in dark for 24h, adjusting pH to 7.0, dialyzing for 24h, and freeze drying at 4 deg.C.

(3) An enzyme method comprises the following steps: preparing 2g glutenin solution, adding 0.04g polyphenol (procyanidin, catechol, and curcumin) into 100mL water, adding laccase or polyphenol oxidase (20U/mL), stirring at 30 deg.C for 18h, dialyzing for 24h, freeze drying, and refrigerating at 4 deg.C.

The present application further investigates the effect of polyphenol modification on glutenin free amino group content and free thiol content. The content of free amino groups in glutenin is determined by an o-phthalaldehyde method. The free sulfhydryl content is determined by a sulfhydryl kit (Nanjing institute of bioengineering).

The results are shown in FIG. 1. Wherein G represents glutenin; GU stands for sonicated glutenin; GPr represents a glutenin/procyanidin non-covalent complex; GCa, represents a glutenin/catechin non-covalent complex; GCu represents a glutenin/curcumin non-covalent complex; GPrU represents glutenin-procyanidin covalent complex; GCaU stands for glutenin-catechin covalent complex; GCuU stands for glutenin-curcumin covalent complex.

As shown in fig. 1(a), ultrasonic treatment, or non-covalent treatment with procyanidin, catechin, and curcumin, did not significantly affect the content of free amino groups in glutenin. Procyanidine, catechin and curcumin are subjected to covalent modification, so that the content of free amino groups of glutenin can be remarkably reduced. This result suggests that the polyphenol can form a covalent complex through the free amino groups of glutenin. Wherein the curcumin-glutenin covalent complex has the lowest free amino group content. This result indicates that the extent of covalent cross-linking of curcumin and glutenin is maximal under the same conditions.

As shown in fig. 1(b), ultrasonic treatment or non-covalent modification of procyanidin, catechin and curcumin can significantly increase the content of free thiol in glutenin. Compared with non-covalent modification, the content of free sulfydryl of glutenin can be obviously reduced by covalent modification of procyanidine, catechin and curcumin. This result suggests that the polyphenol can also form covalent complexes through the free thiol groups of glutenin. Wherein the curcumin-glutenin covalent complex has the lowest free thiol content. This result indicates that the extent of covalent cross-linking of curcumin and glutenin is maximal under the same conditions.

FIG. 2 shows the effect of polyphenol modification on the hydrophobicity of glutenin surface and the intrinsic fluorescence spectrum.

The experimental method is as follows:

surface hydrophobicity: a2 mg/ml sample solution was prepared with 0.01M phosphate buffer, pH 9, diluted to a concentration gradient of 0.05-2mg/ml, 5. mu.l of hydrophobic fluorescent probe dye (ANS) was added, and 200. mu.l of each was added to a 96-well blackboard. Setting the excitation wavelength to be 390nm by using a microplate reader, setting the emission spectrum to be 470nm, measuring the fluorescence value, taking the fluorescence value and the protein concentration as a standard curve, and expressing the surface hydrophobicity of the sample by using the slope.

Endogenous fluorescence: preparing 2mg/ml sample solution, respectively adding 200 μ l of the sample solution into a 96-hole blackboard, and scanning the fluorescence intensity of the sample by using an enzyme-labeling instrument within the range of 300-400nm of the excitation wavelength and the emission spectrum. The change in the fluorescence intensity of the sample within the emission spectrum is recorded.

In fig. 2, G represents glutenin; GU stands for sonicated glutenin; GPr represents a glutenin/procyanidin non-covalent complex; GCa, represents a glutenin/catechin non-covalent complex; GCu represents a glutenin/curcumin non-covalent complex; GPrU represents glutenin-procyanidin covalent complex; GCaU stands for glutenin-catechin covalent complex; GCuU stands for glutenin-curcumin covalent complex.

As shown in fig. 2(a), ultrasonic treatment, or non-covalent/covalent modification of procyanidin, catechin, curcumin can significantly increase the surface hydrophobicity of glutenin. Wherein the covalent modification increases the hydrophobicity of the glutenin surface more than the non-covalent modification. This result suggests that covalent modification of polyphenols can in turn promote the formation of glutenin network structures by increasing the surface hydrophobicity of glutenins.

As shown in fig. 2(b), sonication, or non-covalent/covalent modification of procyanidins, catechins, curcumin, can increase the intensity of endogenous fluorescence of glutenin. This result indicates that various treatments induce unfolding of glutenin. Wherein the covalent modification increases endogenous fluorescence intensity of glutenin more than the non-covalent modification. This result suggests that covalent modification of polyphenols can in turn promote the formation of glutenin network structures by increasing the unfolding of glutenins.

The present application further investigates the effect of polyphenol modification on glutenin particle size and turbidity. The experimental method comprises the following steps:

particle size: a0.1 mg/ml sample solution was prepared, and the particle size was measured by a particle size analyzer (LS 13320).

Turbidity: a1 mg/ml sample solution was prepared. The absorbance at 660nm was measured by an ultraviolet spectrophotometer, and the turbidity was expressed as the absorbance.

The results are shown in FIG. 3. Wherein G represents glutenin; GU stands for sonicated glutenin; GPr represents a glutenin/procyanidin non-covalent complex; GCa, represents a glutenin/catechin non-covalent complex; GCu represents a glutenin/curcumin non-covalent complex; GPrU represents glutenin-procyanidin covalent complex; GCaU stands for glutenin-catechin covalent complex; GCuU stands for glutenin-curcumin covalent complex.

As shown in fig. 3(a), ultrasonic treatment, or non-covalent/covalent modification of procyanidin, catechin, curcumin can increase the particle size of glutenin. This result indicates that various treatments induced glutenin aggregation.

Wherein the covalent modification increases the particle size of the glutenin more than the non-covalent modification. This result suggests that covalent modification of polyphenols may induce formation of glutenin-polyphenol-glutenin polymers.

As shown in fig. 3(b), sonication, or non-covalent/covalent modification of procyanidins, catechins, curcumin, can increase the turbidity of glutenin. This result indicates that various treatments induced glutenin aggregation.

Wherein the covalent modification provides a greater increase in turbidity to the glutenin than the non-covalent modification. This result suggests that covalent modification of polyphenols may induce formation of glutenin-polyphenol-glutenin polymers.

Example 3 preparation of frozen dough.

Mixing 7g of glutenin-polyphenol compound, 7g of gliadin and 86g of wheat starch by a V-5 mixer, and mixing the mixed sample with 50g of water to prepare dough. The dough is wrapped with preservative film, frozen at-18 deg.C for 14 days, and then thawed at 4 deg.C. Wherein the glutenin-polyphenol complex is prepared by four different methods (non-covalent and covalent) in examples 1 and 2, respectively.

Comparative example 1A dough was prepared by mixing 7g of glutenin, 7g of gliadin and 86g of wheat starch using a V-5 mixer and mixing the mixed sample with 50g of water. The dough is wrapped with preservative film, frozen at-18 deg.C for 14 days, and then thawed at 4 deg.C.

Comparative example 2A dough was prepared by mixing 7g of sonicated glutenin, 7g of gliadin and 86g of wheat starch using a V-5 mixer and mixing the mixed sample with 50g of water. The dough is wrapped with preservative film, frozen at-18 deg.C for 14 days, and then thawed at 4 deg.C. Wherein the glutenin treated by ultrasonic wave is as follows: preparing 2g of glutenin solution, adding into 100mL of water, adjusting pH to 9.0, shearing at high speed for 2min (23000 r/min), dissolving thoroughly, homogenizing, performing ultrasonic treatment (400W, 20kHz, 2s working, 2s stopping, ultrasonic treatment for 20min), adjusting pH to 7.0, dialyzing for 24h, freeze-drying, and refrigerating at 4 deg.C.

The prepared frozen dough was subjected to a performance test.

(1) Rheology study of frozen dough.

Specifically, the frozen dough was subjected to frequency oscillation testing in the linear viscoelastic region using a TA rheometer test stand. The measurement conditions are 25mm Peltier, interval 1000 μm, temperature 25 deg.C, angular frequency 0.1-10 Hz, and stress 1 Pa. Before the measurement, the sample temperature should be kept at 25 ℃. The storage modulus (elastic modulus G') and loss modulus (viscous modulus G ") of the frozen dough were recorded, and the complex modulus (G ×) was calculated using the formula: g ═ [ (G') 2+ (G ") 2]^1/2。

The frozen dough was subjected to creep recovery testing using a TA rheometer. The measurement conditions were 25mm Peltier, a pitch of 1000 μm, a temperature of 25 ℃, a stress of 250Pa, a creep of 300s, and a recovery of 300 s. The sample temperature was set to 25 ℃ before measurement. The strain and recovery data is recorded and,

the relative recovery rate can then be calculated by the following formula:

in the formula S_300sMaximum strain at creep stage; s_600sIs the final strain in the recovery phase.

FIG. 4 is a graph showing the effect of glutenin-polyphenol complexes on the complex modulus (a), creep recovery ability (b) and hardness (c) of frozen dough. Wherein G represents a frozen dough to which glutenin is added; GU represents the frozen dough with added sonicated glutenin; GPr represents frozen dough with glutenin/procyanidin non-covalent complex added; GCa, represents frozen dough with glutenin/catechin non-covalent complex added; GCu stands for frozen dough with glutenin/curcumin non-covalent complex added; GPrU represents frozen dough with glutenin-procyanidin covalent complex added; GCaU stands for frozen dough with glutenin-catechin covalent complex added; GCuU stands for frozen dough with glutenin-curcumin covalent complex added.

The complex modulus (G) of the dough can be used to characterize the strength of the dough. As shown in fig. 4(a), the addition of sonicated glutenin, or a non-covalent complex of glutenin/catechin, glutenin/curcumin, slightly increased the strength of the frozen dough. The addition of the glutenin/procyanidin non-covalent complex can greatly improve the strength of the frozen dough. The addition of glutenin-polyphenol covalent complex can significantly increase the strength of the frozen dough. Wherein the effect of adding glutenin-curcumin covalent complex is optimal.

Determination of creep recovery capability can be used to evaluate the viscoelastic properties of the dough, with higher strain values indicating weaker structure. As shown in fig. 4(b), the viscoelastic properties of the frozen dough were improved by the addition of the sonicated glutenin, the glutenin/polyphenol non-covalent complex, and the glutenin-polyphenol covalent complex. Wherein the effect of adding glutenin-curcumin covalent complex is optimal. In addition, the addition of both glutenin/polyphenol non-covalent complex and glutenin-polyphenol covalent complex can improve the recovery of the frozen dough. Wherein the effect of adding glutenin-curcumin covalent complex is optimal.

(2) Determination of the rheological hardness of the frozen dough.

The speed of measurement was 1mm/s using a TA texture analyzer. The probe uses a P/36R cylindrical probe, a force sensing element is 10kg, the trigger force is 8N, and the compression ratio is 70%.

FIG. 4(c) is the result of the effect of the glutenin-polyphenol complex on the firmness of frozen dough.

As shown in fig. 4(c), the addition of sonicated glutenin, or a glutenin/catechin, glutenin/curcumin non-covalent complex, had no significant effect on the firmness of the frozen dough. The addition of the glutenin/procyanidin non-covalent complex can greatly improve the hardness of the frozen dough. The addition of glutenin-polyphenol covalent complex can significantly increase the firmness of the frozen dough. Wherein the effect of adding glutenin-curcumin covalent complex is optimal.

(3) Study of microstructure of frozen dough.

mu.L of fluorescein isothiocyanate (0.1mg/mL) was added to 1mg of the frozen dough, and the microstructure was observed with a fluorescence microscope.

Figure 5 is a graph of the effect of glutenin-polyphenol complexes on the microstructure of frozen dough. A is frozen dough added with glutenin; b is frozen dough added with ultrasonic-treated glutenin; c is frozen dough added with glutenin/procyanidine non-covalent compound; d is frozen dough added with glutenin/catechin non-covalent compound; e is frozen dough added with glutenin/curcumin non-covalent compound; f is frozen dough added with glutenin-procyanidine covalent compound; g is frozen dough added with glutenin-catechin covalent compound; h is frozen dough with glutenin-curcumin covalent complex added.

As shown in FIG. 5A, the starch granules were irregular in the frozen dough (as indicated by the range circled by the small circles) and the glutenin network structure was disrupted. Irregular starch was also observed in FIG. 2B/C/E/G. In FIG. 5D/F/H, the presence of irregular starch was not substantially observed, and the starch granules were coated with glutenin. And the glutenin-curcumin covalent compound is added, so that the antifreeze performance is optimal.

Example 4 preparation of frozen dough bread.

Preparation of dough: 95g of low gluten flour, 5g of glutenin-polyphenol complex, 50g of water, 3g of dry yeast, 8g of sucrose, 2g of milk powder, 1g of salt and 0.5g of bread improver (Angel Yeast GmbH). The dough is wrapped with preservative film, frozen at-18 deg.C for 14 days, and then thawed at 4 deg.C. The thawed dough was proofed at 35 deg.C and 85% relative humidity for 50min, then baked at 210 deg.C for 20min, and cooled to room temperature.

Wherein the glutenin-polyphenol compound is prepared by different methods and different polyphenol types according to the method, and the bread prepared by different methods is obtained.

The bread properties obtained by different methods were measured.

(1) Specific volume and hardness of the frozen dough bread were measured.

The bread specific volume is measured by a bread volume measuring instrument. The hardness of the bread is measured by a TA texture analyzer at a measuring speed of 1 mm/s. The probe uses a P/36R cylindrical probe, a force sensing element is 10kg, the trigger force is 8N, and the compression ratio is 70%.

FIG. 6 is a graph of the effect of glutenin-polyphenol complexes on the specific volume and firmness of frozen dough. Wherein G is frozen dough bread added with glutenin; GU is frozen dough bread added with ultrasonic-treated glutenin; GPr is frozen dough bread added with non-covalent glutenin/procyanidin complex; gca is frozen dough bread added with glutenin/catechin non-covalent complex; gcu is frozen dough bread added with glutenin/curcumin non-covalent complex; GprU is frozen dough bread added with glutenin-procyanidin covalent compound. GcaU is a frozen dough bread to which a glutenin-catechin covalent complex is added. The GcuU is frozen dough bread added with glutenin-curcumin covalent compound.

As shown in fig. 6, the addition of glutenin-polyphenol covalent complex both increased the specific volume and decreased the firmness of the frozen dough bread. Wherein, the effect of adding the glutenin-curcumin covalent compound is optimal.

FIG. 7 effect of glutenin-curcumin covalent complexes of different cross-linking modes on frozen dough specific volume and hardness. The GcuU is frozen dough bread added with the glutenin-curcumin covalent compound prepared by an ultrasonic free radical method. The GcuA is frozen dough bread added with glutenin-curcumin covalent compound prepared by an alkaline method. The GcuE is frozen dough bread added with glutenin-curcumin covalent complex prepared by an enzyme method.

As shown in fig. 7, the addition of the glutenin-polyphenol covalent complex prepared by the ultrasonic radical method and the alkaline method can increase the specific volume of the frozen dough bread and reduce the hardness of the frozen dough bread, which is superior to the glutenin-polyphenol covalent complex prepared by the enzymatic method.

In conclusion, the glutenin-polyphenol compound is prepared, and particularly, three polyphenols, namely catechin, curcumin and procyanidine, and glutenin are subjected to covalent crosslinking to be used as a frozen dough modifier, so that the strength of the frozen dough is improved, the viscoelastic property, the recovery capability and the freezing resistance of the frozen dough are improved, and the freezing resistance of a gluten network structure can be improved, so that the occurrence of the deterioration phenomenon of the frozen dough is prevented, the specific volume of the frozen bread prepared from the frozen dough is increased, and the hardness of the frozen dough bread is reduced.