Ice crystal resistant frozen dough and application thereof in baked food

Abstract

The invention provides ice crystal resistant frozen dough and application thereof in baked food. Comprising the following steps: S1, uniformly mixing weighed flour, salt, white granulated sugar and dry yeast; s2, adding water and the gel loaded with the deacylated antifreeze polypeptide-astragalus membranaceus polyphenol coupling agent, and uniformly stirring to prepare fresh dough with smooth surface; s3, cutting the fresh dough into small dough, wrapping the small dough with a preservative film, quickly freezing the small dough in a refrigerator at the temperature of-40 DEG C for 80 minutes until the central temperature of the dough reaches-18 DEG C, and freezing the dough to obtain the frozen dough. The gel containing the sodium alginate and the deacylated antifreeze polypeptide-astragalus membranaceus polyphenol coupling agent is prepared, and the deacylated antifreeze polypeptide-astragalus membranaceus polyphenol coupling agent is added into the frozen dough, so that quality reduction caused by oxidation in the storage process of the frozen dough is reduced, and the rheological property of the frozen dough is remarkably improved; the gel is added into the frozen dough, so that the generation of ice crystals in the frozen dough is effectively inhibited, and the nutritive value of the dough is improved by adding the astragalus membranaceus polyphenols.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to ice crystal resistant frozen dough and application thereof in baked food. Background Art

[0002] Frozen dough technology is an innovative process that emerged in the mid-to-late 20th century with the rapid development of the food industry. Its core is to block the fermentation and deterioration of dough through low-temperature freezing, thereby extending the shelf life and maintaining baking characteristics. This technology has completely changed the production model of the traditional baking industry and has become an indispensable part of the modern food industry system. Frozen dough inhibits yeast activity and stabilizes the gluten network by precisely controlling the three core parameters of freezing rate, water activity and glass transition temperature. Early technologies caused the dough to have a decreased gas retention after thawing due to freezing damage, resulting in volume shrinkage, rough texture and other problems. With the application of antifreeze agents and improvers, as well as the popularization of new freezing processes such as liquid nitrogen quick freezing, the specific volume recovery rate of modern frozen dough after thawing can reach more than 95%. my country still faces many technical difficulties in frozen dough technology. For example, ice crystals will form during the freezing process of frozen dough, which will damage the dough structure. The formation of ice crystals will cause physical damage to the gluten network in the dough, affecting the quality of the dough and the volume, texture and taste of the baked products. The surface moisture of the frozen dough will be consumed, and the internal moisture will slowly move to the surface, causing the loss of moisture in the dough. Over time, the reduction in moisture will cause cracks on the surface, affecting the quality and appearance of the frozen dough. Moisture migration will occur in the frozen dough during storage, resulting in uneven local moisture content in the dough, affecting the uniformity and quality of the baked products. Summary of the invention

[0003] Technical problems to be solved: In view of the above technical problems, the purpose of the present invention is to provide an anti-ice crystal frozen dough and its application in baked food, and prepare gel by combining sodium alginate and deacylated antifreeze polypeptide-astragalus polyphenol coupling agent. Soy protein is hydrolyzed with bromelain to generate specific antifreeze active polypeptides, and then chymosin is used to catalyze the deacylation reaction of the antifreeze polypeptide, and the deacylated polypeptide molecules enhance the stability and emulsification of the polypeptides; the polyphenols in astragalus are extracted with a composite enzyme of β-glucosidase and polygalacturonase, which improves the yield and bioavailability of astragalus polyphenols and enhances the antioxidant activity of polyphenols; the deacylated antifreeze polypeptide forms a coupling agent with the polyphenols extracted by the composite enzyme, and the formed coupling agent is added to the frozen dough to enhance the structure of the gluten network, reduce the quality degradation of the frozen dough due to oxidation during storage, improve the elastic properties of the frozen dough, and significantly improve the rheological properties of the frozen dough.

[0004] Technical solution: The invention discloses an anti-ice crystal frozen dough, wherein a gel loaded with a deacylated antifreeze polypeptide-astragalus polyphenol coupling agent is added into the frozen dough. An anti-ice crystal frozen dough comprises the following ingredients: 50-60 parts of flour, 0.3-0.5 parts of salt, 25-30 parts of water, 4-6 parts of yeast, and 1-3 parts of gel loaded with a deacylated antifreeze polypeptide-astragalus polyphenol coupling agent. Furthermore, the preparation steps of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent are as follows: S1. Prepare 15-20% soy protein solution, add bromelain for enzymatic hydrolysis, and after the enzymatic hydrolysis, treat the hydrolyzate in boiling water for 5-10 minutes to terminate the hydrolysis and prepare antifreeze polypeptide; S2. adding 1% chymotrypsin to the prepared antifreeze polypeptide for enzymatic hydrolysis to prepare a deacylated antifreeze polypeptide; S3. After drying in an oven, the astragalus was crushed and sieved, and water, β-glucosidase and polygalacturonase were added for ultrasonic extraction to prepare an astragalus polyphenol extract; S4. The prepared deacylated antifreeze polypeptide and astragalus polyphenol extract were homogenized at a speed of 20000-25000 rpm for 5-20 min, and freeze-dried to prepare a deacylated antifreeze polypeptide-astragalus polyphenol coupling agent; S5. Add deacylated antifreeze polypeptide-astragalus polyphenol coupling agent to the sodium alginate solution, wherein the volume ratio of the sodium alginate solution to the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent is 1:1, and prepare a gel loaded with the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent. Furthermore, in step S1, the ratio of bromelain to soy protein solution is 1 g: (15-20) mL, the enzymolysis time is 30-40 min, and the enzymolysis temperature is 40-50° C. Furthermore, in step S2, the solid-liquid ratio of astragalus to water is 1 g:(15-20) mL, and the addition ratio of astragalus, β-glucosidase and polygalacturonase is 1:(0.02-0.05):0.02. Furthermore, the ultrasonic conditions in step S2 are: extraction temperature 40-60° C., extraction time 2-3 h, and ultrasonic power 200-300 W. Furthermore, in step S3, the ratio of deacylated antifreeze polypeptide to astragalus polyphenol extract is 1:(45-50). Furthermore, the ice crystal resistant frozen dough comprises the following steps: (1) putting flour, salt, water, yeast, and gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent into a dough bowl, and kneading repeatedly by hand until the dough becomes smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen. Furthermore, the ice crystal resistant frozen dough is used in baked foods. Beneficial effects: 1. The present invention prepares a gel containing sodium alginate and a deacylated antifreeze polypeptide-astragalus polyphenol coupling agent. The sodium alginate aqueous solution has a relatively high viscosity, which is beneficial to improving the stability of the gel. The addition of the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent further improves the antioxidant performance and biocompatibility of the gel. The gel is applied to frozen dough to enhance the network structure of the dough, effectively absorb and retain moisture, and effectively inhibit the formation of ice crystals in the frozen dough. The addition of astragalus polyphenol improves the nutritional value of the dough. 2. The present invention forms a coupling agent with the deacylated antifreeze polypeptide and the polyphenol extracted by the complex enzyme, and hydrogen bonds are formed between the hydroxyl group in the polyphenol molecule and the amino group or carbonyl group in the polypeptide, and the polar group in the polyphenol molecule and the charged amino acid residue on the surface of the polypeptide are combined by electrostatic attraction. The formed coupling agent is added to the frozen dough to enhance the structure of the gluten network, reduce the quality degradation of the frozen dough due to oxidation during storage, improve the elastic properties of the frozen dough, and significantly improve the rheological properties of the frozen dough. 3. The present invention uses bromelain to enzymatically hydrolyze soybean protein to generate specific antifreeze active polypeptides. The polypeptides with antifreeze activity form hydrogen bonds with water molecules in the prism plane of ice crystals, thereby inhibiting the formation of ice crystals in frozen dough. Chymotrypsin catalyzes the deacylation reaction of the antifreeze polypeptide, which reduces the isoelectric point of the polypeptide through the deacylation reaction, exposes the hydrophobic groups inside the polypeptide molecules, thereby increasing the hydrophilicity of the polypeptide; the deacylated polypeptide molecules have higher surface activity and more uniform particle size distribution, thereby enhancing the stability and emulsification of the polypeptide. 4. The present invention uses a composite enzyme of β-glucosidase and polygalacturonase to extract polyphenols in Astragalus. β-glucosidase can decompose polysaccharides and glycoside compounds in Astragalus into smaller molecules, thereby increasing the concentration of free polyphenol compounds; polygalacturonase can destroy the structure of cell walls and increase the permeability of cell walls by degrading pectin and galacturonic acid ester bonds in Astragalus, thereby releasing more bound polyphenol compounds; the combined action of β-glucosidase and polygalacturonase not only improves the yield and bioavailability of Astragalus polyphenols, but also enhances the antioxidant activity of polyphenols. Astragalus polyphenols can inhibit the growth of microorganisms in frozen dough, increase the nutritional value of dough, and significantly improve the stability of frozen dough. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a sensory evaluation diagram of Examples 5-8 and Comparative Examples 6-11. DETAILED DESCRIPTION The present invention proposes an anti-ice crystal frozen dough and its application in baked food. In order to make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention will be further described in detail with reference to the embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Example 1 The preparation steps of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent are as follows: S1. Prepare 2 mL of 15% soy protein solution, add 0.1 g of bromelain for enzymatic hydrolysis, and after 30 min of enzymatic hydrolysis, treat the hydrolyzate in boiling water for 6 min to terminate the hydrolysis and prepare antifreeze polypeptide; S2. adding 1% chymotrypsin to the prepared antifreeze polypeptide for enzymatic hydrolysis to prepare a deacylated antifreeze polypeptide; S3. After drying in an oven, the astragalus was crushed and sieved, 3 g of astragalus was weighed, 45 mL of water, 0.06 g of β-glucosidase and 0.06 g of polygalacturonase were added for ultrasonic extraction at 40 ° C, extraction time 2 h, ultrasonic power 200 W, and astragalus polyphenol extract was prepared; S4. 1 mL of the prepared deacylated antifreeze polypeptide and 45 mL of astragalus polyphenol extract were homogenized at 20,000 rpm / min for 10 min, and freeze-dried to prepare a deacylated antifreeze polypeptide-astragalus polyphenol coupling agent; S5. Add deacylated antifreeze polypeptide-astragalus polyphenol coupling agent to the sodium alginate solution, wherein the volume ratio of the sodium alginate solution to the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent is 1:1, and prepare a gel loaded with the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent. Example 2 The preparation steps of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent are as follows: S1. Prepare 2 mL of 15% soy protein solution, add 0.1 g of bromelain for enzymatic hydrolysis, and after 30 min of enzymatic hydrolysis, treat the hydrolyzate in boiling water for 6 min to terminate the hydrolysis and prepare antifreeze polypeptide; S2. adding 1% chymotrypsin to the prepared antifreeze polypeptide for enzymatic hydrolysis to prepare a deacylated antifreeze polypeptide; S3. After drying in an oven, the astragalus was crushed and sieved, 3 g of astragalus was weighed, 45 mL of water, 0.09 g of β-glucosidase and 0.06 g of polygalacturonase were added for ultrasonic extraction at a temperature of 40 ° C, an extraction time of 2 h, and an ultrasonic power of 200 W to prepare an astragalus polyphenol extract; S4. 1 mL of the prepared deacylated antifreeze polypeptide and 45 mL of astragalus polyphenol extract were homogenized at 20,000 rpm / min for 10 min, and freeze-dried to prepare a deacylated antifreeze polypeptide-astragalus polyphenol coupling agent; S5. Add deacylated antifreeze polypeptide-astragalus polyphenol coupling agent to the sodium alginate solution, wherein the volume ratio of the sodium alginate solution to the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent is 1:1, and prepare a gel loaded with the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent. Example 3 The preparation steps of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent are as follows: S1. Prepare 2 mL of 15% soy protein solution, add 0.1 g of bromelain for enzymatic hydrolysis, and after 30 min of enzymatic hydrolysis, treat the hydrolyzate in boiling water for 6 min to terminate the hydrolysis and prepare antifreeze polypeptide; S2. adding 1% chymotrypsin to the prepared antifreeze polypeptide for enzymatic hydrolysis to prepare a deacylated antifreeze polypeptide; S3. After drying in an oven, the astragalus was crushed and sieved, 3 g of astragalus was weighed, 45 mL of water, 0.12 g of β-glucosidase and 0.06 g of polygalacturonase were added for ultrasonic extraction at 40 ° C, extraction time 2 h, ultrasonic power 200 W, and astragalus polyphenol extract was prepared; S4. 1 mL of the prepared deacylated antifreeze polypeptide and 45 mL of astragalus polyphenol extract were homogenized at 20,000 rpm / min for 10 min, and freeze-dried to prepare a deacylated antifreeze polypeptide-astragalus polyphenol coupling agent; S5. Add deacylated antifreeze polypeptide-astragalus polyphenol coupling agent to the sodium alginate solution, wherein the volume ratio of the sodium alginate solution to the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent is 1:1, and prepare a gel loaded with the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent. Example 4 The preparation steps of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent are as follows: S1. Prepare 2 mL of 15% soy protein solution, add 0.1 g of bromelain for enzymatic hydrolysis, and after 30 min of enzymatic hydrolysis, treat the hydrolyzate in boiling water for 6 min to terminate the hydrolysis and prepare antifreeze polypeptide; S2. adding 1% chymotrypsin to the prepared antifreeze polypeptide for enzymatic hydrolysis to prepare a deacylated antifreeze polypeptide; S3. After drying in an oven, the astragalus was crushed and sieved, 3 g of astragalus was weighed, 45 mL of water, 0.15 g of β-glucosidase and 0.06 g of polygalacturonase were added for ultrasonic extraction at 40 ° C, extraction time 2 h, ultrasonic power 200 W, and astragalus polyphenol extract was prepared; S4. 1 mL of the prepared deacylated antifreeze polypeptide and 45 mL of astragalus polyphenol extract were homogenized at 20,000 rpm / min for 10 min, and freeze-dried to prepare a deacylated antifreeze polypeptide-astragalus polyphenol coupling agent; S5. Add deacylated antifreeze polypeptide-astragalus polyphenol coupling agent to the sodium alginate solution, wherein the volume ratio of the sodium alginate solution to the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent is 1:1, and prepare a gel loaded with the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent. Comparative Example 1 The difference between this comparative example and Example 3 is that no deacylated antifreeze polypeptide is prepared, specifically as follows: The preparation steps of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent are as follows: S1. Prepare 2 mL of 15% soy protein solution, add 0.1 g of bromelain for enzymatic hydrolysis, and after 30 min of enzymatic hydrolysis, treat the hydrolyzate in boiling water for 6 min to terminate the hydrolysis and prepare antifreeze polypeptide; S2. After drying in an oven, the astragalus was crushed and sieved, 3 g of astragalus was weighed, 45 mL of water, 0.12 g of β-glucosidase and 0.06 g of polygalacturonase were added for ultrasonic extraction at 40 ° C, extraction time 2 h, ultrasonic power 200 W, and astragalus polyphenol extract was prepared; S4. 1 mL of the prepared antifreeze polypeptide and 45 mL of astragalus polyphenol extract were homogenized at 20000 rpm / min for 10 min, and freeze-dried to prepare an antifreeze polypeptide-astragalus polyphenol coupling agent; S5. Add antifreeze polypeptide-astragalus polyphenol coupling agent to the sodium alginate solution, the volume ratio of the sodium alginate solution to the antifreeze polypeptide-astragalus polyphenol coupling agent is 1:1, and prepare a gel loaded with the antifreeze polypeptide-astragalus polyphenol coupling agent. Comparative Example 2 The difference between this comparative example and Example 3 is that no β-glucosidase is added, specifically as follows: The preparation steps of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent are as follows: S1. Prepare 2 mL of 15% soy protein solution, add 0.1 g of bromelain for enzymatic hydrolysis, and after 30 min of enzymatic hydrolysis, treat the hydrolyzate in boiling water for 6 min to terminate the hydrolysis and prepare antifreeze polypeptide; S2. adding 1% chymotrypsin to the prepared antifreeze polypeptide for enzymatic hydrolysis to prepare a deacylated antifreeze polypeptide; S3. After drying in an oven, the astragalus was crushed and sieved, 3 g of astragalus was weighed, 45 mL of water and 0.06 g of polygalacturonase were added for ultrasonic extraction at 40 ° C, extraction time 2 h, ultrasonic power 200 W, and astragalus polyphenol extract was prepared; S4. 1 mL of the prepared deacylated antifreeze polypeptide and 45 mL of astragalus polyphenol extract were homogenized at 20,000 rpm / min for 10 min, and freeze-dried to prepare a deacylated antifreeze polypeptide-astragalus polyphenol coupling agent; S5. Add deacylated antifreeze polypeptide-astragalus polyphenol coupling agent to the sodium alginate solution, wherein the volume ratio of the sodium alginate solution to the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent is 1:1, and prepare a gel loaded with the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent. Comparative Example 3 The difference between this comparative example and Example 3 is that no polygalacturonase is added, specifically as follows: The preparation steps of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent are as follows: S1. Prepare 2 mL of 15% soy protein solution, add 0.1 g of bromelain for enzymatic hydrolysis, and after 30 min of enzymatic hydrolysis, treat the hydrolyzate in boiling water for 6 min to terminate the hydrolysis and prepare antifreeze polypeptide; S2. adding 1% chymotrypsin to the prepared antifreeze polypeptide for enzymatic hydrolysis to prepare a deacylated antifreeze polypeptide; S3. After drying in an oven, the astragalus was crushed and sieved, 3 g of astragalus was weighed, 45 mL of water and 0.12 g of β-glucosidase were added for ultrasonic extraction at 40 ° C, extraction time 2 h, ultrasonic power 200 W, and astragalus polyphenol extract was prepared; S4. 1 mL of the prepared deacylated antifreeze polypeptide and 45 mL of astragalus polyphenol extract were homogenized at 20,000 rpm / min for 10 min, and freeze-dried to prepare a deacylated antifreeze polypeptide-astragalus polyphenol coupling agent; S5. Add deacylated antifreeze polypeptide-astragalus polyphenol coupling agent to the sodium alginate solution, wherein the volume ratio of the sodium alginate solution to the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent is 1:1, and prepare a gel loaded with the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent. Comparative Example 4 The difference between this comparative example and comparative example 3 is that no deacylated antifreeze polypeptide is prepared and β-glucosidase is added. Specifically, the steps for preparing the gel loaded with antifreeze polypeptide-astragalus polyphenol coupling agent are as follows: S1. Prepare 2 mL of 15% soy protein solution, add 0.1 g of bromelain for enzymatic hydrolysis, and after 30 min of enzymatic hydrolysis, treat the hydrolyzate in boiling water for 6 min to terminate the hydrolysis and prepare antifreeze polypeptide; S2. After drying in an oven, the astragalus was crushed and sieved, 3 g of astragalus was weighed, 45 mL of water and 0.06 g of polygalacturonase were added for ultrasonic extraction at 40 ° C, extraction time 2 h, and ultrasonic power 200 W to prepare astragalus polyphenol extract; S3. 1 mL of the prepared antifreeze polypeptide and 45 mL of astragalus polyphenol extract were homogenized at 20000 rpm / min for 10 min, and freeze-dried to prepare an antifreeze polypeptide-astragalus polyphenol coupling agent; S4. Add antifreeze polypeptide-astragalus polyphenol coupling agent to the sodium alginate solution, the volume ratio of the sodium alginate solution to the antifreeze polypeptide-astragalus polyphenol coupling agent is 1:1, and prepare a gel loaded with the antifreeze polypeptide-astragalus polyphenol coupling agent. Comparative Example 5 The difference between this comparative example and comparative example 3 is that no deacylated antifreeze polypeptide is prepared and polygalacturonase is added. Specifically, the steps for preparing the gel loaded with antifreeze polypeptide-astragalus polyphenol coupling agent are as follows: S1. Prepare 2 mL of 15% soy protein solution, add 0.1 g of bromelain for enzymatic hydrolysis, and after 30 min of enzymatic hydrolysis, treat the hydrolyzate in boiling water for 6 min to terminate the hydrolysis and prepare antifreeze polypeptide; S2. After drying in an oven, the astragalus was crushed and sieved, 3 g of astragalus was weighed, 45 mL of water and 0.06 g of polygalacturonase were added for ultrasonic extraction at 40 ° C, extraction time 2 h, and ultrasonic power 200 W to prepare astragalus polyphenol extract; S3. 1 mL of the prepared antifreeze polypeptide and 45 mL of astragalus polyphenol extract were homogenized at 20000 rpm / min for 10 min, and freeze-dried to prepare an antifreeze polypeptide-astragalus polyphenol coupling agent; S4. Add antifreeze polypeptide-astragalus polyphenol coupling agent to the sodium alginate solution, the volume ratio of the sodium alginate solution to the antifreeze polypeptide-astragalus polyphenol coupling agent is 1:1, and prepare a gel loaded with the antifreeze polypeptide-astragalus polyphenol coupling agent. Performance Testing (1) Hardness analysis A gel sample with consistent height and horizontal surface is placed in the center of the texture analyzer test platform for a puncture test. The gel sample is subjected to a puncture test to determine the hardness value of the gel system. The gel strength value at a puncture depth of 15 mm is calculated as the hardness value of the gel. Table 1 Hardness and embedding rate of gels prepared in Examples 1-4 and Comparative Examples 1-5 Hardness(N) Embedding rate (%) Example 1 0.92 88.41 Example 2 0.94 88.59 Example 3 1.12 91.35 Example 4 1.08 89.62 Comparative Example 1 0.72 86.48 Comparative Example 2 0.83 87.37 Comparative Example 3 0.86 87.52 Comparative Example 4 0.54 85.64 Comparative Example 5 0.61 85.75 As can be seen from Table 1, the gel prepared in Example 3 has the highest hardness and the highest embedding rate. This may be because the addition ratio of β-glucosidase and polygalacturonase affects the extraction rate of astragalus polyphenols, and the polyphenol content affects the interaction between coupling agent molecules, thereby changing the cross-linking density and structural stability of the gel; the deacylation reaction will enhance the mechanical strength of the gel by changing the molecular conformation and the degree of acylation. Example 5 An ice crystal resistant frozen dough comprises the following steps: (1) 50 parts of flour, 0.3 parts of salt, 25 parts of water, 4 parts of yeast, and 2 parts of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Example 1 are placed in a dough bowl, and kneaded repeatedly by hand until the dough becomes smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen. Example 6 An ice crystal resistant frozen dough comprises the following steps: (1) 50 parts of flour, 0.3 parts of salt, 25 parts of water, 4 parts of yeast, and 2 parts of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Example 2 were placed in a dough bowl, and kneaded repeatedly by hand until the dough became smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen. Example 7 An ice crystal resistant frozen dough comprises the following steps: (1) 50 parts of flour, 0.3 parts of salt, 25 parts of water, 4 parts of yeast, and 2 parts of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Example 3 were placed in a dough bowl, and kneaded repeatedly by hand until the dough became smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen. Example 8 An ice crystal resistant frozen dough comprises the following steps: (1) 50 parts of flour, 0.3 parts of salt, 25 parts of water, 4 parts of yeast, and 2 parts of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Example 4 were placed in a dough bowl, and kneaded repeatedly by hand until the dough became smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen. Comparative Example 6 The difference between this comparative example and Example 7 is that the gel loaded with antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Comparative Example 1 is used. An anti-ice crystal frozen dough comprises the following steps: (1) 50 parts of flour, 0.3 parts of salt, 25 parts of water, 4 parts of yeast, and 2 parts of the gel loaded with antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Comparative Example 1 were placed in a dough bowl, and kneaded repeatedly by hand until the dough became smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen. Comparative Example 7 The difference between this comparative example and Example 7 is that the gel loaded with the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Comparative Example 2 is used. An ice crystal resistant frozen dough comprises the following steps: (1) 50 parts of flour, 0.3 parts of salt, 25 parts of water, 4 parts of yeast, and 2 parts of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Comparative Example 2 were placed in a dough bowl, and kneaded repeatedly by hand until the dough became smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen. Comparative Example 8 The difference between this comparative example and Example 7 is that the gel loaded with the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Comparative Example 3 is used. An ice crystal resistant frozen dough comprises the following steps: (1) 50 parts of flour, 0.3 parts of salt, 25 parts of water, 4 parts of yeast, and 2 parts of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Comparative Example 3 were placed in a dough bowl, and kneaded repeatedly by hand until the dough became smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen. Comparative Example 9 The difference between this comparative example and Example 7 is that the gel loaded with antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Comparative Example 4 is used. An anti-ice crystal frozen dough comprises the following steps: (1) 50 parts of flour, 0.3 parts of salt, 25 parts of water, 4 parts of yeast, and 2 parts of the gel loaded with antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Comparative Example 4 were placed in a dough bowl, and kneaded repeatedly by hand until the dough became smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen. Comparative Example 10 The difference between this comparative example and Example 7 is that the gel loaded with antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Comparative Example 5 is used. An anti-ice crystal frozen dough comprises the following steps: (1) 50 parts of flour, 0.3 parts of salt, 25 parts of water, 4 parts of yeast, and 2 parts of the gel loaded with antifreeze polypeptide-astragalus polyphenol coupling agent prepared in Comparative Example 5 were placed in a dough bowl, and kneaded repeatedly by hand until the dough became smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen. Comparative Example 11 The difference between this comparative example and Example 7 is that the gel loaded with the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent is not added. A frozen dough comprises the following steps: (1) Put 50 parts of flour, 0.3 parts of salt, 25 parts of water, and 4 parts of yeast into a dough bowl and knead the dough repeatedly by hand until the dough becomes smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen. Performance Testing (1) Freezable water content Take 12 mg of dough and place it in a special aluminum box for differential calorimetry scanner to prevent water loss. Then place the aluminum box containing the dough in a refrigerator for freezing. After 10 days of freezing, take out the sample and quickly transfer it to the sample slot of the differential calorimetry scanner. The melting enthalpy of the dough is calculated by comprehensive thermal analysis software, and the calculation formula for the freezable water content is as follows: Among them, Δ fus H m Indicates the endothermic enthalpy of water, J / g; ΔH w is the melting enthalpy of the dough, J; m is the mass of the dough, g; W A is the moisture content of the dough, g / g. (2) Fermentation capacity determination At 30°C, the volume of CO2 gas produced by yeast fermentation in a dough prepared with certain ingredients within a specified time is measured. The displacement of carbon dioxide gas is measured by the displacement method, that is, the gas production of the dough, expressed in mL. The gas production is used to represent the fermentation power of the dough. Table 2 Freezable water content and fermentation capacity of dough prepared in Examples 5-8 and Comparative Examples 6-11 Freezable water content (%) Fermentation capacity (mL) Example 5 47.63 772 Example 6 46.98 785 Example 7 45.62 820 Example 8 46.81 796 Comparative Example 6 50.36 734 Comparative Example 7 48.95 759 Comparative Example 8 48.67 763 Comparative Example 9 52.00 750 Comparative Example 10 51.74 757 Comparative Example 11 54.09 692 As can be seen from Table 2, the dough prepared in Example 7 has the lowest freezable water content and the strongest dough fermentation ability. This is because the polypeptide with antifreeze activity forms hydrogen bonds with water molecules in the prism plane of ice crystals, thereby inhibiting the formation of ice crystals in frozen dough, the deacylated antifreeze polypeptide forms a coupling agent with the polyphenol extracted by the complex enzyme, the hydroxyl groups in the polyphenol molecules form hydrogen bonds with the amino or carbonyl groups of the polypeptides, and the polar groups in the polyphenol molecules are combined with the charged amino acid residues on the surface of the polypeptides through electrostatic attraction. The gel loaded with the antifreeze polypeptide-astragalus polyphenol coupling agent is added to the frozen dough to enhance the structure of the gluten network, reduce the formation of ice crystals in the frozen dough, thereby reducing the bindable water content in the frozen dough, and reducing the adverse effects of yeast on the dough fermentation ability due to ice crystal formation. The frozen dough prepared in Examples 5-8 and Comparative Examples 6-11 was thawed at 4° C. for 20 h, and the thawed dough was put into a fermentation box for fermentation at a temperature of 32° C. and a relative humidity of 85% for 60 min, and then baked at 180° C. for 15 min to prepare bread. Performance Testing (1) Specific volume of bread The mass and volume of bread were determined by weight method and rapeseed displacement method respectively. The formula for calculating the specific volume of bread is as follows: Table 3 Specific volume of bread prepared in Examples 5-8 and Comparative Examples 6-11 Specific volume (mL / g) Specific volume (mL / g) Example 5 4.62 Comparative Example 7 4.37 Example 6 4.85 Comparative Example 8 4.49 Example 7 5.16 Comparative Example 9 3.85 Example 8 5.01 Comparative Example 10 3.94 Comparative Example 6 4.04 Comparative Example 11 3.71 As can be seen from Table 3, the specific volume of the bread prepared in Example 7 is the largest, which may be because the gel loaded with antifreeze polypeptide-astragalus polyphenol coupling agent is added to the dough to enhance the gluten strength of the dough, allowing the dough to retain more gas, thereby increasing the specific volume of the bread after baking. (2) Bread texture analysis Use a physical property analyzer to measure the texture of bread. Cut the bread into slices and take the two middle slices for texture measurement. Physical property analyzer measurement conditions and parameters: Select TPA mode and use P / 36R probe; pre-test speed 2.0mm / s, test speed 1.0mm / s, post-test speed 4.0mm / s; probe compression ratio 40%, repeat compression twice, interval time 15s. Table 4 Texture characteristics of bread prepared in Examples 5-8 and Comparative Examples 6-11 Hardness(g) Elasticity(g) Chewability Resilience Example 5 364.83 0.96 352.64 0.45 Example 6 357.94 0.98 346.98 0.47 Example 7 324.52 1.12 320.81 0.54 Example 8 348.61 1.07 338.56 0.49 Comparative Example 6 400.74 0.84 389.67 0.36 Comparative Example 7 384.72 0.87 370.24 0.41 Comparative Example 8 379.65 0.92 365.72 0.43 Comparative Example 9 426.76 0.78 406.73 0.30 Comparative Example 10 411.86 0.80 400.65 0.32 Comparative Example 11 440.87 0.61 422.96 0.23 As can be seen from Table 4, the bread prepared in Example 7 has the smallest hardness, the largest elasticity, the smallest chewiness, and the largest rebound resilience. This may be because the dough to which the gel loaded with antifreeze polypeptide-astragalus polyphenol coupling agent is added has a better expansion state after fermentation, resulting in better texture characteristics of the bread and improving the sensory quality of the bread. (3) Sensory evaluation of bread The sensory evaluation panel consisted of 20 trained members who evaluated the bread's color, flavor, mouthfeel, texture and overall acceptance. 1-9 points represent the acceptance of each sensory index of the bread sample, with 1 point indicating that it is very unpopular and 9 points indicating that it is very liked. from Figure 1 It can be seen that the sensory evaluation index of Example 7 has the highest comprehensive score. The gel loaded with antifreeze polypeptide-astragalus polyphenol coupling agent is added to the frozen dough to enhance the structure of the gluten network, reduce the quality degradation of the frozen dough due to oxidation during storage, improve the elastic properties of the frozen dough and significantly improve the rheological properties of the frozen dough, and the prepared bread is more accepted by the public. The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the above disclosed methods and technical contents without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. An ice crystal resistant frozen dough, characterized in that: The frozen dough is added with gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent.

2. The ice crystal resistant frozen dough according to claim 1, characterized in that: The invention comprises the following ingredients: 50-60 parts of flour, 0.3-0.5 parts of salt, 25-30 parts of water, 4-6 parts of yeast, and 1-3 parts of gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent.

3. The ice crystal resistant frozen dough according to claim 2, characterized in that: The preparation steps of the gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent are as follows: S1. Prepare 15-20% soy protein solution, add bromelain for enzymolysis, and after the enzymolysis, treat the hydrolyzate in boiling water for 5-10 minutes to terminate the hydrolysis and prepare antifreeze polypeptide; S2. adding 1% chymotrypsin to the prepared antifreeze polypeptide for enzymatic hydrolysis to prepare a deacylated antifreeze polypeptide; S3. After drying in an oven, the astragalus was crushed and sieved, and water, β-glucosidase and polygalacturonase were added for ultrasonic extraction to prepare an astragalus polyphenol extract; S4. The deacylated antifreeze polypeptide and the astragalus polyphenol extract were homogenized at a speed of 20000-25000 rpm for 5-20 min, and freeze-dried to prepare a deacylated antifreeze polypeptide-astragalus polyphenol coupling agent; S5. Add deacylated antifreeze polypeptide-astragalus polyphenol coupling agent to the sodium alginate solution, wherein the volume ratio of the sodium alginate solution to the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent is 1:(1-3), to prepare a gel loaded with the deacylated antifreeze polypeptide-astragalus polyphenol coupling agent.

4. The ice crystal resistant frozen dough according to claim 3, characterized in that: In step S1, the ratio of bromelain to soy protein solution is 1 g: (15-20) mL, the enzymolysis time is 30-40 min, and the enzymolysis temperature is 40-50° C.

5. The ice crystal resistant frozen dough according to claim 3, characterized in that: In the step S2, the material-liquid ratio of astragalus to water is 1 g:(15-20) mL, and the addition ratio of astragalus, β-glucosidase and polygalacturonase is 1:(0.02-0.05):0.

02.

6. The ice crystal resistant frozen dough according to claim 3, characterized in that: The ultrasonic conditions in step S2 are: extraction temperature 40-60° C., extraction time 2-3 h, and ultrasonic power 200-300 W.

7. The ice crystal resistant frozen dough according to claim 3, characterized in that: In step S3, the ratio of the deacylated antifreeze polypeptide to the astragalus polyphenol extract is 1:(45-50).

8. The method for preparing ice crystal resistant frozen dough according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) putting flour, salt, water, yeast, and gel loaded with deacylated antifreeze polypeptide-astragalus polyphenol coupling agent into a dough bowl, and kneading repeatedly by hand until the dough becomes smooth and elastic; (2) Divide the dough into small pieces, wrap them with plastic wrap, and then freeze them in a -40°C refrigerator for 90 minutes until the center temperature of the dough reaches -18°C, and then store them frozen.

9. Use of the ice crystal resistant frozen dough according to any one of claims 1 to 7 in baked foods.

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