Method for balancing nutrition and eating quality of steamed buns by using wheat bran active protein

Abstract

The invention discloses a method for balancing nutrition and eating quality of steamed buns by using wheat bran active protein, belongs to the technical field of grain and food processing, and solves the problems that protein denaturation is easily caused and the extraction energy consumption and cost are high in a wheat bran protein extraction method at the present stage. The method comprises the following steps: extracting wheat bran active protein based on a water extraction and salting-out method, and adding the wheat bran active protein into wheat flour to obtain the steamed bun rich in wheat bran active protein, according to the method, the bran raw material is subjected to enzymolysis under the synergistic effect of cellulase and neutral protease, the energy consumption cost is not increased while the yield of the active protein of the bran is increased, and the bran protein is extracted through a water extraction gradient salting-out method, so that the protein activity is kept. The high-activity protein can significantly enhance the fermentation gas-holding property of the dough, improve the specific volume and taste of the steamed bun, enhance the eating quality of the steamed bun and effectively enhance the nutritional function of the steamed bun at the same time under a certain addition amount, so that the steamed bun product gives consideration to both the nutrition and the eating quality.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of grain and food processing, and particularly relates to a method for balancing the nutrition and eating quality of steamed buns by using wheat bran active protein. BACKGROUND

[0002] Wheat is one of the main crops for human beings, and has unique processing characteristics. Wheat flour ground from wheat can meet the needs of making various kinds of noodles such as bread, steamed buns, noodles, biscuits and the like. However, during the process of wheat milling, bran is produced as a main by-product, and the annual output is more than 20 million tons. The bran is rich in nutrients, accounting for 60%-80% of the total nutrients of wheat kernels, but the rough taste caused by the high content of dietary fiber makes it less acceptable to consumers. Therefore, most of the bran is used as livestock feed, and the utilization rate in food processing is less than 20%. This low-value utilization not only causes a large amount of nutrients to be lost, but also makes the over-processed flour products gradually evolve into high-energy and low-nutrition foods. Therefore, it is an urgent need for the grain industry and social development to improve the deep processing utilization rate of bran components, strengthen the dietary nutrition of flour products, and improve the taste and eating quality of flour products.

[0003] Bran protein is an important component in bran, and its content is only second to that of dietary fiber. Unlike gluten protein in wheat flour, bran protein is mainly composed of non-gluten protein (globulin and albumin). The amino acid composition is more balanced, and the content of lysine is 2 times higher than that of gluten protein, which can prevent "lysine deficiency" for a long time. In addition, bran protein contains rich bioactive peptides, which play an important role in reducing cholesterol, lowering blood pressure, lowering blood sugar, antioxidant, and especially weight loss and prevention of obesity. At present, the research on bran protein mainly focuses on the preparation of concentrates and bioactive peptides to meet the protein needs of special groups, and the functional properties (foaming ability, emulsifying properties, gelation, etc.) in food applications are evaluated. However, there is no report on how bran protein specifically affects the processing quality of flour products, which limits its deep processing utilization in the field of flour products.

[0004] In recent years, whole grain foods have gradually entered people's vision, and with the continuous in-depth study of the characteristics and components of bran, the excellent food functional properties of bran protein have been continuously explored. Researchers have found that bran protein not only can be used as a nutritional enhancer for flour products, but also has the potential to improve the processing quality of flour products. Therefore, extracting and purifying bran protein to strengthen the nutritional value and improve the eating quality of flour products is an important solution to overcome the negative effects of whole grain products.

[0005] At present, the raw bran is usually pretreated by ultrasonic wave before extracting the protein from the bran, and the traditional alkali-soluble acid precipitation method is usually used to extract the bran protein. However, this method has significant limitations:

[0006] 1) Although the ultrasonic pretreatment can improve the protein yield, it has high cost and high energy consumption and active loss. The wheat bran needs to be pretreated by ultrasonic wave at high temperature for a long time, which can improve the protein yield but also increases the energy consumption. The cavitation effect of ultrasonic wave can also cause the denaturation of protein. In addition, the cost of ultrasonic hardware equipment is high, which restricts the industrialization promotion.

[0007] 2) When the bran protein is extracted in an alkaline environment by the alkali-soluble acid precipitation method, the protein can be separated by adjusting the pH value, but the damage of strong acid and alkali environment to the function of protein cannot be ignored. The treatment method of alkali-soluble acid precipitation can easily cause the denaturation of protein. The alkaline environment can destroy the secondary and tertiary structures of protein, which can cause the significant decrease of functional properties (such as solubility, foaming property and emulsifying property) of protein. The denaturation not only affects the nutritional value of protein, but also causes the prepared bran active protein to be unable to effectively play its role in improving the texture and strengthening the nutrition of steamed bread, which further affects the balance between the nutrition and food quality of steamed bread and limits its application in food industry.

[0008] The superposition of the two problems makes the bran protein extracted by the existing technology not only difficult to balance the yield and activity, but also unable to effectively play its role in improving the texture and strengthening the nutrition of steamed bread due to the significant loss of functional properties. At present, due to the fine processing of wheat, the structural contradiction between the low-value utilization of wheat by-products bran and important components bran protein and the "high energy and low nutrition" structure of staple food continues to intensify. Therefore, in view of the problems that the bran protein is usually pretreated by ultrasonic wave to improve the protein yield but at the same time increases the energy consumption and equipment cost, and the bran protein is usually extracted by the traditional alkali-soluble acid precipitation method but is easy to cause the denaturation of protein, a method for balancing the nutrition and food quality of steamed bread by bran active protein is proposed to balance the nutrition and food quality of steamed bread, and promote the high-value utilization of wheat by-products. SUMMARY

[0009] The purpose of the present application is to solve the problems of denaturation and high energy consumption and cost in the extraction of bran protein at present, and to apply the bran protein, which is a wheat homologous protein resource, to the nutrition and processing quality improvement of steamed bread and other staple foods, so as to improve the high-value utilization of bran protein components of wheat processing by-products and realize the double improvement of nutrition and food quality of steamed bread and other staple foods.

[0010] The application is achieved by a method for balancing the nutrition of bran active protein and the quality of steamed buns, comprising the following steps:

[0011] S10, taking commercially available bran raw materials, crushing the bran raw materials through a 100-mesh sieve, and pretreating the bran raw materials to obtain bran active protein based on a water extraction gradient salting-out method, for standby use;

[0012] S20, taking commercially available wheat flour, adding the prepared bran active protein to the wheat flour at a proportion of 0.5-4% (w / w) to prepare bran active protein-wheat flour mixed powder, for standby use;

[0013] S30, based on a steamed bun processing technology, adding water with a weight of 40-50% of the mixed powder to the bran active protein-wheat flour mixed powder, with a water temperature of 25-35℃, and stirring the bran active protein-wheat flour mixed powder by using a pin-type and a face bowl to form a dough, and then forming the dough into a steamed bun embryo;

[0014] S40, taking the prepared steamed bun embryo and placing it in a constant-temperature and constant-humidity fermentation box, and then steaming the steamed bun embryo to obtain a steamed bun rich in bran active protein.

[0015] Preferably, the method for extracting bran active protein based on a water extraction salting-out method comprises the following steps:

[0016] S101, taking the sieved bran raw materials, adding deionized water to the sieved bran raw materials so that the ratio of the bran raw materials to the deionized water is 1:5-1:15 to prepare a bran water solution, and adjusting the pH value to 6-7.5, for standby use;

[0017] S102, adding neutral protease and cellulase to the bran water solution to perform mixed enzymatic hydrolysis treatment on the bran water solution by using the neutral protease and the cellulase;

[0018] S103, after the enzymatic hydrolysis, heating the bran water solution to 90℃ for 10 min of enzyme inactivation treatment, and centrifugally separating to obtain supernatant;

[0019] S104, respectively adding 60%-100% ammonium sulfate solution to the supernatant in a gradient, centrifugally collecting ammonium sulfate precipitates after fractional gradient precipitation, dialyzing the ammonium sulfate precipitates to remove salt, and vacuum freeze-drying to obtain bran active protein.

[0020] Preferably, in step S101, the temperature of the bran water solution is 35-45℃.

[0021] Preferably, when the mixed enzymatic hydrolysis treatment is performed on the bran water solution by using the neutral protease and the cellulase, the neutral protease is used in an amount of 0.5-2.0%, and the cellulase is used in a concentration of 0.04-0.08 IU / mL.

[0022] Preferably, in step S30, when the active protein-wheat flour mixed powder is treated by pin and bowl stirring, the dough is formed by pin and bowl stirring for 3-7 min, the dough is rolled 10 times from top to bottom at a tablet press face roller interval of 0.5, then the dough is evenly divided into two pieces, and each piece is hand kneaded for 20-30 times, until the dough is moisturized and shaped, to form steamed bun embryos, which are ready for use.

[0023] Preferably, in step S40, the prepared steamed bun embryos are placed in a constant temperature and humidity fermentation box, the temperature of the fermentation box is 30-40 DEG C, the humidity is 80-90%, and the fermentation time is 30-40 min.

[0024] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0025] In the embodiments of the present application, the wheat bran raw material is treated by cellulase and neutral protease in cooperation, which significantly reduces the energy consumption and cost of extracting the same target amount of active protein from wheat bran compared with conventional ultrasonic treatment. Compared with the traditional alkali dissolution and acid precipitation method, the water extraction gradient salting-out method can ensure the activity of the extracted active protein from wheat bran. Compared with the traditional extraction technology, the high-activity wheat bran protein prepared is more nutritious, the amino acid composition is balanced, and the content of lysine is higher, and lysine is a limiting amino acid in Chinese steamed buns and other flour-based staple foods. The nutrition function of the steamed buns is effectively strengthened by adding the high-activity protein. And the high-activity protein can also significantly enhance the fermentation gas holding capacity of the dough at a certain addition amount, increase the specific volume of the steamed buns, make the internal structure of the steamed buns more soft and fluffy, improve the taste, and thus ensure the eating quality of the steamed buns. At the same time, the content of lysine in the steamed buns is higher, which effectively strengthens the nutrition function of the steamed buns, so that the steamed bun product can improve both nutrition and eating quality. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a specific volume test result diagram of the steamed buns prepared in examples 1-5 and comparative example 1 of the present application.

[0027] Figure 2 shows a texture property test result diagram of the steamed buns prepared in examples 1-5 and comparative example 1 of the present application.

[0028] Figure 3 shows a pore structure test result diagram of the steamed buns prepared in examples 1-5 and comparative example 1 of the present application.

[0029] Figure 4 shows an appearance, taste, flavor, and overall acceptability test result diagram of the steamed buns prepared in examples 1-5 and comparative example 1 of the present application.

[0030] Figure 5 shows a protein content test result diagram of the steamed buns prepared in examples 1-5 and comparative example 1 of the present application.

[0031] Figure 6 Figure 1 shows the results of the lysine content test of steamed buns prepared according to embodiments 1-5 and comparative example 1. DETAILED DESCRIPTION

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application; the description herein and the claims of the application and the above description of the drawings herein are intended to cover all alternatives, modifications, and equivalents of the application falling within the scope of the application; the terms "comprising", "having", "including", and "containing" used herein are meant to be broad and encompass the terms "consisting of", "consisting essentially of", and "substantially consisting of". The terms "first", "second", and the like, used in the description and in the claims herein, are used for distinguishing between similar objects and are not necessarily used to describe a particular sequential order.

[0033] In view of the fact that at present, wheat bran is mostly subjected to ultrasonic pretreatment to increase the protein yield, but at the same time, the energy consumption and equipment cost are increased, and the traditional alkali-soluble acid precipitation method is mostly used to extract and prepare the wheat bran protein, which easily leads to protein denaturation and inactivation. We propose a method for balancing the nutrition and food quality of steamed buns by using active wheat bran protein, wherein the method is implemented as follows: first, the bran raw material is subjected to enzymatic pretreatment, and the active wheat bran protein is extracted based on the water extraction gradient salting-out method to obtain the active wheat bran protein. Then, the commercially available wheat flour is added with the active wheat bran protein in a proportion of 0.5-4.0% (w / w) to the wheat flour to prepare a mixed flour of the active wheat bran protein and the wheat flour, the dough is formed by stirring with a needle and a mortar, the dough is made into a steamed bun embryo, and the steamed bun embryo is steamed to obtain a steamed bun rich in the active wheat bran protein.

[0034] It is considered that at present, the annual output of wheat by-products bran in China is more than 200 million tons, but most of the bran is used as feed or directly discarded due to the rough taste caused by high dietary fiber, while the bran carries 60%-80% of the nutritional essence of wheat kernels, especially lysine content, and these nutrients are lost with the waste. At the same time, due to the fine processing of wheat, the development of staple food such as flour in China is generally faced with the "high energy and low nutrition" dilemma, which also increases the difficulty and cost of processing wheat by-products. The present application promotes the value-added conversion of wheat by-products by converting the bran protein into a high-value-added product. In the embodiments of the present application, the bran raw material is subjected to synergistic treatment by cellulase and neutral protease, the active wheat bran protein is extracted from the bran by using the water extraction gradient salting-out method, and the extraction process is optimized, the active wheat bran protein is added to the wheat flour to process into a steamed bun product, and the nutritional function and processing quality of staple food products such as steamed buns in China are improved. By converting the active ingredients in the bran into a high-value-added product, the value-added conversion of bran is promoted, the wheat processing industry chain is extended, and strong support is provided for the sustainable development of China's health strategy and society and economy.

[0035] Embodiment 1

[0036] The embodiment of the present application provides a method for balancing the nutrition and edible quality of steamed buns by using wheat bran active protein, and the method comprises the following steps:

[0037] S10, commercially available wheat bran is taken as a raw material, the raw material is crushed through a 100-mesh sieve, and the raw material is pretreated to obtain wheat bran active protein by using a water extraction gradient salting-out method, and the wheat bran active protein is reserved;

[0038] S20, commercially available wheat flour is taken, and the prepared wheat bran active protein is added into the wheat flour at a proportion of 0.5% (w / w) to prepare wheat bran active protein-wheat flour mixed powder, and the wheat bran active protein-wheat flour mixed powder is reserved;

[0039] S30, water with a weight of 40% of the wheat bran active protein-wheat flour mixed powder is added into the wheat bran active protein-wheat flour mixed powder based on a steamed bun processing technology, the water temperature is 25℃, the wheat bran active protein-wheat flour mixed powder is stirred and treated by using a needle type and a kneading bowl to form a dough, and the dough is made into a steamed bun embryo, wherein when the wheat bran active protein-wheat flour mixed powder is stirred and treated by using the needle type and the kneading bowl, the dough is formed by stirring and treating for 3 min, the dough is rolled 10 times from top to bottom at a tablet press face roller spacing of 0.5 to exhaust air, then the dough is evenly divided into two blocks, and each block is hand-kneaded for 20 times, so that the dough is moisturized and shaped to form the steamed bun embryo, and the steamed bun embryo is reserved;

[0040] S40, the prepared steamed bun embryo is placed in a constant-temperature and constant-humidity fermentation box, and then the steamed bun embryo is steamed to obtain a steamed bun rich in wheat bran active protein, wherein when the prepared steamed bun embryo is placed in the constant-temperature and constant-humidity fermentation box, the temperature of the fermentation box is 30℃, the humidity is 80%, and the fermentation time is 30 min.

[0041] In the embodiment, the method for extracting the wheat bran active protein based on the water extraction salting-out method comprises the following steps:

[0042] S101, the sieved bran raw material is taken, deionized water is added into the sieved bran raw material, so that the solid-liquid ratio of the bran raw material and the deionized water is 1:5, a bran water solution is prepared, the pH value is adjusted to 6, and the temperature of the bran water solution is 35℃, and the bran water solution is reserved;

[0043] S102, adding neutral protease and cellulase into the bran aqueous solution, and performing mixed enzymatic hydrolysis treatment on the bran aqueous solution by the neutral protease and the cellulase, wherein the neutral protease is used in an amount of 0.5%, the cellulase has a concentration of 0.04 IU / mL, and the synergistic effect of the cellulase and the neutral protease can efficiently decompose cellulose in the bran in a short time and effectively extract protein, thereby reducing energy consumption in the extraction process. Compared with ultrasonic treatment, the enzymatic hydrolysis treatment greatly reduces energy consumption. Meanwhile, in the traditional alkali dissolution and acid precipitation method, bran protein is treated under alkaline conditions, which can easily cause protein denaturation and reduce the functional properties of the protein. This denaturation not only affects the nutritional value of the protein, but also limits its application in the food industry. In contrast, the enzymatic hydrolysis combined with the water extraction gradient salting-out method adopted in the present application can reduce energy consumption and effectively avoid protein denaturation.

[0044] S103, after the enzymatic hydrolysis, centrifugal separation is performed to obtain supernatant, ammonium sulfate is added into the supernatant in a gradient manner until a 60% ammonium sulfate solution concentration is reached, and after fractional gradient precipitation, the ammonium sulfate precipitate is collected by centrifugation, desalted by dialysis, and vacuum freeze-dried to obtain bran active protein.

[0045] In the embodiment of the present application, the water extraction gradient salting-out method is used, which can ensure the activity of the extracted bran protein compared with the traditional alkali dissolution and acid precipitation method, and the synergistic treatment of cellulase and neutral protease significantly reduces the energy consumption for extracting the same target amount of bran active protein. Compared with the traditional extraction technology, the high-activity bran protein prepared has more nutritious and balanced amino acid composition, especially higher content of lysine, which is a limiting amino acid in Chinese steamed buns and other staple foods. The addition of the bran active protein effectively enhances the nutritional function of the steamed buns. At the same time, the high-activity protein can also significantly enhance the fermentation gas retention of the dough, increase the specific volume of the steamed buns, make the internal structure of the steamed buns more soft and fluffy, and improve the taste, so that steamed buns with balanced nutrition and food quality are finally prepared.

[0046] Embodiment 2

[0047] The embodiment of the present application provides a method for balancing the nutrition and food quality of steamed buns by using bran active protein, and the method comprises the following steps:

[0048] S10, taking bran raw materials, crushing the bran raw materials through a 100-mesh sieve, and pretreating the bran raw materials to prepare bran active protein based on a water extraction gradient salting-out method for standby use;

[0049] S20, taking wheat flour, adding the prepared bran active protein to the wheat flour at a proportion of 1% (w / w) to prepare bran active protein-wheat flour mixed powder for standby use;

[0050] S30, based on the steamed bun processing technology, water with 45% of the weight of the mixed flour of wheat bran active protein-wheat flour is added, the water temperature is 30 DEG C, the mixed flour of wheat bran active protein-wheat flour is stirred by using a needle type and a kneading bowl to form a dough, and the dough is made into a steamed bun embryo, wherein, when the mixed flour of wheat bran active protein-wheat flour is stirred by using a needle type and a kneading bowl, the dough is formed by stirring for 4 min, the dough is rolled 10 times from top to bottom at a distance of 0.5 between the rollers of a tablet press to remove air, then the dough is evenly divided into two parts, and each part is kneaded by hand for 20 times until the dough is moisturized and shaped to form a steamed bun embryo, which is ready for use;

[0051] S40, the prepared steamed bun embryo is placed in a constant temperature and humidity fermentation box, and then steamed to obtain a steamed bun rich in wheat bran active protein, wherein, when the prepared steamed bun embryo is placed in the constant temperature and humidity fermentation box, the temperature of the fermentation box is 30 DEG C, the humidity is 85%, and the fermentation time is 30 min.

[0052] In this embodiment, the method for extracting wheat bran active protein based on water extraction and salt precipitation comprises:

[0053] S101, the sieved bran raw material is taken, deionized water is added to the sieved bran raw material, so that the solid-liquid ratio of the bran raw material to the deionized water is 1:10, a bran aqueous solution is prepared, the pH value is adjusted to 6.5, and the temperature of the bran aqueous solution is 35 DEG C, which is ready for use;

[0054] S102, neutral protease and cellulase are added to the bran aqueous solution, and the bran aqueous solution is subjected to mixed enzymatic hydrolysis treatment by the neutral protease and the cellulase, wherein, when the bran aqueous solution is subjected to mixed enzymatic hydrolysis treatment by the neutral protease and the cellulase, the neutral protease is used in an amount of 0.5%, and the cellulase has a concentration of 0.04 IU / mL;

[0055] S103, after the enzymatic hydrolysis is completed, the supernatant is obtained by centrifugal separation, ammonium sulfate is added to the supernatant in a gradient manner until the concentration of the 80% ammonium sulfate solution is reached, the ammonium sulfate precipitate is collected by centrifugal separation after fractional gradient precipitation, the ammonium sulfate precipitate is dialyzed to remove salt, and then vacuum freeze-dried to obtain wheat bran active protein.

[0056] Example 3

[0057] The method for balancing the nutrition and food quality of steamed buns by using wheat bran active protein provided in the embodiments of the present application comprises:

[0058] S10, commercially available bran raw material is taken, the bran raw material is crushed through a 100-mesh sieve, and the bran raw material is pretreated, wheat bran active protein is prepared based on a water extraction and gradient salt precipitation method, and the wheat bran active protein is ready for use;

[0059] S20, commercially available wheat flour is taken, and the prepared bran active protein is added into the wheat flour at a proportion of 2.0% (w / w) to prepare a bran active protein-wheat flour mixed powder for standby;

[0060] S30, based on a steamed bun processing process, water with a proportion of 45% of the weight of the bran active protein-wheat flour mixed powder is added into the bran active protein-wheat flour mixed powder, the water temperature is 30℃, and the bran active protein-wheat flour mixed powder is stirred and treated by using a pin-type and a kneading bowl to form a dough, and the dough is prepared into a steamed bun embryo, wherein when the bran active protein-wheat flour mixed powder is stirred and treated by using a pin-type and a kneading bowl, the dough is formed by stirring and treating for 5 min by using a pin-type and a kneading bowl, the dough is rolled 10 times from top to bottom at a tablet press face roller spacing of 0.5 to drive air, and then the dough is evenly divided into two blocks and is kneaded by hand for 30 times respectively until the dough is moisturized and shaped to prepare the steamed bun embryo for standby.

[0061] S40, the prepared steamed bun embryo is placed in a constant-temperature and constant-humidity fermentation box, and then the steamed bun embryo is steamed to obtain a steamed bun rich in bran active protein, wherein when the prepared steamed bun embryo is placed in the constant-temperature and constant-humidity fermentation box, the temperature of the fermentation box is 35℃, the humidity is 85%, and the fermentation time is 35 min.

[0062] In this embodiment, the method for extracting bran active protein based on a water extraction and salt precipitation method comprises the following steps:

[0063] S101, the sieved bran is taken, deionized water is added into the sieved bran, so that the solid-liquid ratio of the bran and the deionized water is 1:10, a bran water solution is prepared, the pH value is adjusted to 7.0, and the temperature of the bran water solution is 35℃ for standby;

[0064] S102, neutral protease and cellulase are added into the bran water solution, and the bran water solution is subjected to mixed enzymatic hydrolysis treatment by using the neutral protease and the cellulase, wherein when the bran water solution is subjected to the mixed enzymatic hydrolysis treatment by using the neutral protease and the cellulase, the neutral protease is used in an amount of 1%, and the cellulase is used in a concentration of 0.06 IU / mL.

[0065] S103, after the enzymatic hydrolysis is completed, ammonium sulfate is added into the supernatant in a gradient until the concentration of the 100% ammonium sulfate solution is reached, the ammonium sulfate precipitate is collected by centrifugation after fractional gradient precipitation, the ammonium sulfate precipitate is dialyzed to remove salt, and then vacuum freeze-drying is performed to obtain bran active protein.

[0066] Example 4

[0067] The method for balancing the nutrition and food quality of a steamed bun by using bran active protein provided in the embodiments of the present application comprises the following steps:

[0068] S10, taking commercially available bran raw materials, crushing the bran raw materials through a 100-mesh screen, and pretreating the bran raw materials, to obtain bran active protein based on a water extraction gradient salting-out method, for standby use;

[0069] S20, taking commercially available wheat flour, adding the prepared bran active protein to the wheat flour at a proportion of 3.0% (w / w), to prepare bran active protein-wheat flour mixed flour, for standby use;

[0070] S30, based on a steamed bun processing technology, adding water with a powder weight of 45% to the bran active protein-wheat flour mixed flour, with a water temperature of 35°C, and stirring and kneading the bran active protein-wheat flour mixed flour by using a needle-type and a kneading bowl to form a dough, and then forming a steamed bun embryo by kneading the dough by hand for 30 times, until the dough is moisturized and shaped, for standby use.

[0071] S40, placing the prepared steamed bun embryo in a constant-temperature and constant-humidity fermentation box, and then steaming the steamed bun embryo to obtain a steamed bun rich in bran active protein, wherein, when the prepared steamed bun embryo is placed in the constant-temperature and constant-humidity fermentation box, the temperature of the fermentation box is 35°C, the humidity is 90%, and the fermentation time is 40 minutes.

[0072] In this embodiment, the method for extracting bran active protein based on a water extraction salting-out method comprises the following steps:

[0073] S101, taking the sieved bran raw materials, adding deionized water to the sieved bran raw materials, so that the solid-liquid ratio of the bran raw materials to the deionized water is 1:10, to prepare a bran water solution, adjusting the pH value to 7.0, and adjusting the temperature of the bran water solution to 40°C, for standby use.

[0074] S102, adding neutral protease and cellulase to the bran water solution, and performing mixed enzymatic hydrolysis treatment on the bran water solution by using the neutral protease and the cellulase, wherein, when the mixed enzymatic hydrolysis treatment is performed on the bran water solution by using the neutral protease and the cellulase, the neutral protease is used in an amount of 1.5%, and the cellulase is used in a concentration of 0.06 IU / mL.

[0075] S103, after the enzymatic hydrolysis is completed, adding ammonium sulfate to the supernatant in a gradient manner until the concentration of 100% saturated ammonium sulfate is reached, collecting the ammonium sulfate precipitate by centrifugation after fractional gradient precipitation, dialyzing the ammonium sulfate precipitate to remove salt, and then vacuum freeze-drying to obtain bran active protein.

[0076] Example 5

[0077] The embodiment of the present application provides a method for balancing the nutrition and edible quality of steamed buns by using wheat bran active protein, and the method comprises the following steps:

[0078] S10, commercially available bran raw materials are taken, the bran raw materials are pretreated, the bran raw materials are sieved through a 100-mesh sieve, wheat bran active protein is extracted based on a water extraction salting-out method, the wheat bran active protein is prepared, and the wheat bran active protein is reserved;

[0079] S20, commercially available wheat flour is taken, the prepared wheat bran active protein is added into the wheat flour at a proportion of 4.0% (w / w), a wheat bran active protein-wheat flour mixed powder is prepared, and the wheat bran active protein-wheat flour mixed powder is reserved;

[0080] S30, water with a weight of 50% of the wheat bran active protein-wheat flour mixed powder is added into the wheat bran active protein-wheat flour mixed powder based on a steamed bun processing technology, the water temperature is 30 DEG C, the wheat bran active protein-wheat flour mixed powder is stirred and treated by using a needle type and a kneading bowl, a dough is formed, the dough is prepared into a steamed bun embryo, when the wheat bran active protein-wheat flour mixed powder is stirred and treated by using the needle type and the kneading bowl, the dough is formed by stirring and treating for 7 min, the dough is rolled 10 times from top to bottom at a tablet press face roller spacing of 0.5 to drive air, then the dough is evenly divided into two blocks, and the two blocks are hand kneaded for 30 times respectively, until the dough is moisturized and shaped, and the steamed bun embryo is prepared, and the steamed bun embryo is reserved;

[0081] S40, the prepared steamed bun embryo is placed in a constant-temperature and constant-humidity fermentation box, then the steamed bun embryo is steamed, and a steamed bun rich in wheat bran active protein is obtained, when the prepared steamed bun embryo is placed in the constant-temperature and constant-humidity fermentation box, the temperature of the fermentation box is 35 DEG C, the humidity is 90%, and the fermentation time is 40 min.

[0082] In the embodiment, the method for extracting the wheat bran active protein based on the water extraction salting-out method comprises the following steps:

[0083] S101, the sieved bran raw materials are taken, deionized water is added into the sieved bran raw materials, so that the material-liquid ratio of the bran raw materials and the deionized water is 1:15, a bran water solution is prepared, the pH value is adjusted to 7.5, and the temperature of the bran water solution is 45 DEG C, and the bran water solution is reserved;

[0084] S102, neutral protease and cellulase are added into the bran water solution, and the bran water solution is subjected to mixed enzymolysis treatment by using the neutral protease and the cellulase, wherein, when the bran water solution is subjected to the mixed enzymolysis treatment by using the neutral protease and the cellulase, the neutral protease is used in an amount of 2.0%, and the cellulase is used in a concentration of 0.08 IU / mL;

[0085] S103, after the enzymolysis, centrifugal separation was performed to obtain supernatant, ammonium sulfate was added into the supernatant in gradient until reaching 100% saturated ammonium sulfate concentration, and after fractional gradient precipitation, the ammonium sulfate precipitate was collected by centrifugation, desalted by dialysis, and vacuum freeze-dried to obtain the wheat bran active protein.

[0086] Example 6

[0087] The method of this example was the same as that of Example 3, except that in step S30, the wheat bran active protein was added to the bread formula flour at a proportion of 2% (w / w), and a bread added with wheat bran active protein flour was made.

[0088] Comparative Example 1

[0089] The method of this comparative example was the same as that of Example 5, except that in step S30, no wheat bran active protein was added, i.e., the wheat bran active protein was added to the wheat flour at a proportion of 0% (w / w).

[0090] Comparative Example 2

[0091] The method of this comparative example was the same as that of Example 3, except that in step S30, the wheat bran active protein was added to the bread formula flour at a proportion of 0% (w / w), and a bread added with wheat bran active protein flour was made.

[0092] Performance test:

[0093] Steamed bun quality determination: The steamed buns prepared in Examples 1-5 and Comparative Example 1 of the present application were taken, the millet volume displacement method was used to determine the specific volume of the steamed buns, a texture analyzer was used to determine the hardness, chewiness and other texture properties, and a professional digital camera combined with Image J software was used to take pictures of the steamed bun images for microscopic observation of the pore structure.

[0094] Specifically, when determining the specific volume of the steamed bun, the steamed bun was first weighed using a balance, and then the volume of the steamed bun was determined using the millet volume displacement method. The steamed bun was gently placed into a container filled with millet, ensuring that the steamed bun was completely covered by the millet. The steamed bun was slowly taken out, and at this time the millet in the container would decrease due to the occupation of the steamed bun. The volume of the decreased millet was the volume of the steamed bun.

[0095] When determining the elasticity texture of the steamed bun, the steamed bun was sliced, and the middle three slices were taken for determination of the texture of the steamed bun. The P / 36R probe TPA mode was used for determination, the compression ratio of the steamed bun was 50%, the pre-measurement speed, the middle measurement speed and the post-measurement speed were 3 mm / s, 2 mm / s and 5 mm / s, respectively, the trigger force was 5 g, the interval time was 5 s, and each sample was repeated at least 5 times in parallel.

[0096] When the pore structure of steamed buns is measured, the steamed bun slices are photographed, and the steamed bun images are analyzed using Image J software, the area of 4x4 cm in the middle of each steamed bun slice is intercepted, and the porosity of the steamed bun slice is calculated. 2

[0097] It should be noted that the specific volume of steamed buns is one of the key indicators for measuring the quality of steamed buns, and directly reflects the steamed buns. The greater the specific volume value, the more soft and delicious the steamed buns are. Table 1 and Figure 1 The specific volume test results of the steamed buns prepared in Examples 1-5 and Comparative Example 1 of the present application are shown. The results show that with the addition of wheat bran active protein, the specific volume of steamed buns first shows an upward trend, reaches a peak at the addition amount of Example 3, but the specific volume of steamed buns with added wheat bran active protein is higher than that of Comparative Example 1 overall. This result shows that the appropriate addition of wheat bran active protein helps to improve the softness of steamed buns and improve the taste.

[0098] The texture properties of steamed buns, as a key indicator for evaluating the quality of food, directly affect the taste acceptance of the product. Table 1 and Figure 2 The texture property test results of the steamed buns prepared in Examples 1-5 and Comparative Example 1 of the present application are shown. Through texture analysis of steamed buns with different proportions of added wheat bran active protein and after fermentation and steaming, it is found that with the increase of the addition amount of wheat bran active protein, the hardness and chewiness of steamed buns show a trend of first decreasing and then increasing, and compared with Comparative Example 1, the steamed bun samples with added wheat bran active protein are overall reduced in these two indicators. This change means that the addition of wheat bran active protein effectively improves the softness of steamed buns, making the steamed buns more soft and delicious.

[0099] Table 1 and Figure 3 The pore structure test results of the steamed buns prepared in Examples 1-5 and Comparative Example 1 of the present application are shown. As can be seen from Table 1, the specific volume of steamed buns increases after the addition of wheat bran active protein, and the structure is more fluffy; at the same time, the hardness of steamed buns decreases, and the taste is more soft and delicate. Wheat bran active protein may interact with gluten protein, affecting the network structure of gluten protein. In the present application, the different addition amounts of wheat bran active protein affect the aggregation and disaggregation degree of gluten protein molecules, and the dual effect of aggregation and disaggregation affects the network structure of gluten protein. In terms of starch structure, wheat bran active protein can increase the order degree of starch, and promote the formation of more ordered structure of starch molecules in steamed buns. The changes in the structure of gluten protein and starch molecules jointly affect the gas holding property of fermented steamed buns, and then affect the texture and specific volume.

[0100] Table 1 Steamed bun quality test data

[0101] Item Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Specific volume (mL / g) 2.44 ± 0.02 c ]] 2.69 ± 0.03 b ]] 2.85 ± 0.04 a ]] 2.47 ± 0.02 c ]] 2.28 ± 0.03 d ]] 2.15 ± 0.04 e ]] Hardness (g) 2043.28 ± 36.40 b ]] 1734.39 ± 65.43 d ]] 1492.13 ± 56.43 e ]] 1893.16 ± 38.82 c ]] 2036.96 ± 44.41 b ]] 2207.38 ± 40.58 a ]] Chewiness 1766.25 ± 46.35 b ]] 1583.89 ± 39.16 c ]] 1342.41 ± 29.83 d ]] 1765.36 ± 84.23 b ]] 2013.04 ± 72.31 a ]]> 2112.06 ± 28.03 a ]] Porosity (%) 19.23 ± 0.25 d ]] 24.23 ± 0.32 c ]] 36.63 ± 0.14 a ]] 37.22 ± 0.13 a ]] 31.31 ± 0.22 b ]] 15.59 ± 0.25 e ]]

[0102] Table 2 Bread quality test data

[0103] ​ Item Example 6 Comparative Example 2 Specific volume (mL / g) 5.78 ± 0.13 a ]] 4.42 ± 0.16 b ]] Hardness (g) 834.54 ± 40.22 b ]] 1232.45 ± 69.31 a ]] Chewiness 791.43 ± 43.35 b ]] 998.23 ± 63.09 a ]] Porosity (%) 39.22 ± 0.17 a ]] 26.34 ± 0.26 b ]]

[0104] The sensory quality of steamed buns is an important factor affecting the overall quality of the product, which is composed of human vision, olfaction, taste, hearing and touch. The experiment was conducted by 20 (male: female = 10: 10) trained professional evaluators in a sensory evaluation room. The appearance, taste, flavor, overall acceptability of the steamed buns prepared by the present application examples 1-5 and comparative example 1 were tested by using a 9-point hedonic scale, and the test results are shown in Table 3 and Figure 4

[0105] Table 3 Sensory quality and acceptability test data of steamed buns

[0106] Item Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Appearance 7.31 ± 0.11 b ]] 7.82 ± 0.15 a ]] 8.07 ± 0.18 a ]] 7.40 ± 0.14 b ]] 6.92 ± 0.16 c ]] 6.52 ± 0.11 d ]] Texture 7.34 ± 0.16 c ]] 7.81 ± 0.15 b ]] 8.26 ± 0.20 a ]] 7.62 ± 0.19 bc ]] 7.02 ± 0.09 d ]] 6.64 ± 0.12 e ]] Flavor 6.92 ± 0.12 d ]] 7.51 ± 0.04 c ]] 8.01 ± 0.05 b ]] 8.11 ± 0.14 ab ]] 8.23 ± 0.09 a ]] 6.41 ± 0.21 e ]] Internal structure 7.26 ± 0.05 c ]] 7.92 ± 0.12 b ]] 8.41 ± 0.14 a ]] 7.52 ± 0.21 c ]] 6.72 ± 0.17 d ]] 6.54 ± 0.11 d ]] Color 7.92 ± 0.13 b ]] 8.21 ± 0.11 ab ]] 8.23 ± 0.21 ab ]] 8.33 ± 0.09 a ]] 8.05 ± 0.06 b ]] 7.47 ± 0.14 c ]] Overall acceptability 7.55 ± 0.15 cd ]] 8.03 ± 0.09 b ]] 8.35 ± 0.12 a ]] 7.61 ± 0.11 c ]] 7.26 ± 0.18 d ]] 6.81 ± 0.09 e ]]

[0107] Table 4 Sensory quality and acceptability test data of bread

[0108] Item Comparative Example 2 Example 6 Appearance 8.39 ± 0.21 a ]] 7.26 ± 0.12 b ]] Texture 8.46 ± 0.14 a ]] 7.64 ± 0.25 b ]] Flavor 8.31 ± 0.24 a ]] 7.81 ± 0.15 b ]] Internal structure 8.52 ± 0.17 a ]] 7.36 ± 0.36 b ]] Color 8.63 ± 0.07 a ]] 8.05 ± 0.09 b ]] Overall acceptability 8.42 ± 0.09 a ]] 7.51 ± 0.15 b ]]

[0109] As can be seen from Table 3, the steamed buns added with wheat bran active protein have higher scores in appearance, taste, flavor and color compared with comparative example 1, so it can be known that the appearance, taste, flavor, texture and overall acceptability of the steamed buns prepared by the present application examples 1-5 are higher. The addition of an appropriate amount of wheat bran active protein can significantly improve the texture properties of steamed buns, making them softer and easier to chew, and improving the taste.

[0110] Nutrient component analysis: the steamed buns prepared by the present application examples 1-5 and comparative example 1 were respectively tested for protein content (Kjeldahl nitrogen determination method) and amino acid composition (amino acid analyzer) to evaluate the effect of improving nutritional value. Table 5, Figure 5 - Figure 6 shows the nutrient component analysis results.

[0111] Table 5 Nutrient component analysis test of steamed buns

[0112]

[0113] Table 6 Nutrient component analysis test of bread

[0114] Item Example 6 Comparative Example 2 Protein content (g / 100 g) 15.66±0.23 14.19±0.09 Lysine content (g / 100 g) 0.379±0.007 0.293±0.011

[0115] As can be seen from Table 5, by gradient addition of bran active protein, the protein nutrient density of steamed buns is significantly improved, and the problem of lysine deficiency in traditional steamed buns is also solved. By comparing the bread prepared by the present application example 6 with the bread prepared by comparative example 2, the bread prepared by adding bran active protein to the bread flour also has the effect of nutritional fortification and quality improvement (see Table 2, Table 4, Table 6), thereby overcoming the limitations of high temperature and acidic environment during bread preparation, indicating that the wheat bran active protein prepared by the present application has high applicability.​

[0116] In summary, the present application provides a method for balancing the nutritional value and eating quality of steamed buns by using wheat bran active protein. In the embodiments of the present application, the wheat bran raw material is enzymatically hydrolyzed under the synergistic action of cellulase and neutral protease. Compared with ultrasonic treatment, the method improves the protein yield while significantly reducing the energy consumption and cost of extracting the same amount of wheat bran active protein. Compared with the traditional alkali dissolution and acid precipitation method, the water extraction and gradient salting method can ensure the activity of the extracted wheat bran active protein and improve its functional properties. Compared with traditional extraction techniques, the steamed buns prepared by the present application are more nutritious, with a balanced amino acid composition, especially a high content of lysine, which is a limiting amino acid in Chinese steamed buns and other staple foods. The addition of the high-activity protein effectively enhances the nutritional function of the steamed buns. It is worth noting that the high-activity protein can also significantly enhance the fermentation gas retention of the dough at a certain addition amount, increase the specific volume of the steamed buns, make the internal structure of the steamed buns more soft and fluffy, improve the taste, and thus improve the eating quality of the steamed buns. At the same time, the amino acid composition in the steamed buns is more balanced, especially the high content of lysine, which effectively enhances the nutritional function of the steamed buns, making the steamed bun products have both improved nutritional value and eating quality.

[0117] It should be noted that for the foregoing embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited by the order of the described actions, because according to the present application, certain steps can be performed in other order or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0118] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the protection scope of the application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art can still combine, delete or make other adjustments to the features in the embodiments of the present application according to the circumstances without making creative labor, so as to obtain different other technical solutions which do not deviate from the concept of the present application in essence. These technical solutions also fall within the scope of the present application.

Claims

1. A method for balancing the nutritional value of steamed buns and the eating quality of steamed buns by using wheat bran active protein, characterized in that, The method comprises: S10, taking bran raw materials, crushing the bran raw materials through a 100-mesh sieve, and pretreating the bran raw materials to obtain bran active protein based on a water extraction gradient salting-out method, for standby; S20, taking wheat flour, adding the prepared bran active protein to the wheat flour at a proportion of 0.5-4% (w / w), to prepare bran active protein-wheat flour mixed powder, for standby; S30, based on a steamed bun processing technology, adding water with a weight of 45-50% of the powder to the bran active protein-wheat flour mixed powder, with a water temperature of 25-35℃, and stirring to form a dough by using a pin-type and a dough beater, and then forming the dough into a steamed bun embryo; S40, taking the prepared steamed bun embryo, placing it in a constant-temperature and constant-humidity fermentation box for fermentation, and then steaming the steamed bun embryo, to obtain a steamed bun rich in bran active protein.

2. The method for balancing the nutritional value of steamed bread with the eating quality of steamed bread by using wheat bran active protein according to claim 1, characterized in that: The method for extracting bran active protein based on a water extraction gradient salting-out method comprises: S101, taking the sieved bran raw materials, adding deionized water to the sieved bran raw materials, so that the ratio of the bran raw materials to the deionized water is 1:5-1:15, to prepare a bran water solution, adjusting the pH value to 6-7.5, for standby; S102, adding neutral protease and cellulase to the bran water solution, and performing mixed enzymatic hydrolysis treatment on the bran water solution by using the neutral protease and the cellulase; S103, after the enzymatic hydrolysis is completed, heating the bran water solution to 90℃, performing enzyme inactivation treatment for 10 min, and centrifugally separating to obtain supernatant; S104, sequentially adding an ammonium sulfate solution with a concentration gradient of 60%-100% to the supernatant, centrifugally collecting the ammonium sulfate precipitate after fractional gradient precipitation, dialyzing the ammonium sulfate precipitate to remove salt, and vacuum freeze-drying, to obtain bran active protein.

3. The method for balancing the nutritional value of steamed bread with the eating quality of steamed bread by using wheat bran active protein according to claim 2, characterized in that: In step S101, the temperature of the bran water solution is 35-45℃.

4. The method for balancing the nutritional value of steamed bread with the eating quality of steamed bread by using wheat bran active protein according to claim 3, characterized in that: When the mixed enzymatic hydrolysis treatment is performed on the bran water solution by using neutral protease and cellulase, the neutral protease is used in an amount of 0.5-2%, and the cellulase is used in a concentration of 0.04-0.08 IU / mL.

5. The method for balancing the nutritional value of steamed bread with the eating quality of steamed bread by using wheat bran active protein according to claim 4, characterized in that: In step S40, when the bran active protein-wheat flour mixed powder is stirred by using a pin-type and a dough beater, the dough is stirred by using the pin-type and the dough beater for 3-7 min to form a dough, the dough is rolled 10 times from top to bottom at a tablet press face roller spacing of 0.5 to drive air, and then the dough is evenly divided into two blocks, which are kneaded by hand for 20-30 times, respectively, until the dough is moisturized and shaped, to prepare a steamed bun embryo, for standby.

6. The method for balancing the nutritional value of steamed bread with the eating quality of steamed bread by using wheat bran active protein according to claim 1, characterized in that: In step S50, when the prepared steamed bun embryo is placed in a constant-temperature and constant-humidity fermentation box, the temperature of the fermentation box is 30-35℃, the humidity is 80-90%, and the fermentation time is 30-40 min.

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