阅读说明：本技术 一种兼性电荷壳聚糖降解产物的制备方法及其在冷冻面团中的应用 (Preparation method of amphoteric charge chitosan degradation product and application of amphoteric charge chitosan degradation product in frozen dough ) 是由 祝祥威 院佩佩 陈曦 王智珂 蔡冬娜 丁文平 于 2020-11-30 设计创作，主要内容包括：本发明提供一种兼性电荷壳聚糖降解产物的制备方法及其在冷冻面团中的应用,包括如下步骤：将O-羧甲基壳聚糖溶解于pH为5.5的磷酸缓冲液中,配置成高分子水溶液；将该溶液在30-80℃条件下水解30-180分钟,每克O-羧甲基壳聚糖中加入壳聚糖酶的量为50酶活力单位；反应完成后,用120℃油浴加热5-10分钟,灭酶,获得兼性电荷壳聚糖降解产物。将该制备方法制备得到的兼性电荷壳聚糖降解产物添加到面粉中,用于制备冷冻面团,添加量为0.2％-0.8％。利用本发明方法提供的兼性电荷多糖降解产物作为冷冻面团改良剂,可降低冰晶的尺寸大小,抑制面筋蛋白的降解,减少淀粉的回生,提高成品面包的比容。(The invention provides a preparation method of a facultative charge chitosan degradation product and application of the facultative charge chitosan degradation product in frozen dough, which comprises the following steps: dissolving O-carboxymethyl chitosan in a phosphate buffer solution with the pH value of 5.5 to prepare a high-molecular aqueous solution; hydrolyzing the solution at 30-80 deg.C for 30-180 min, wherein the amount of chitosanase added into each gram of O-carboxymethyl chitosan is 50 enzyme activity units; after the reaction is finished, heating the mixture for 5 to 10 minutes by using a 120 ℃ oil bath, and inactivating enzyme to obtain the amphoteric charge chitosan degradation product. The amphoteric charge chitosan degradation product prepared by the preparation method is added into flour for preparing frozen dough, and the addition amount is 0.2-0.8%. The degradation product of the facultative charge polysaccharide provided by the method is used as a frozen dough modifier, so that the size of ice crystals can be reduced, the degradation of mucedin is inhibited, the retrogradation of starch is reduced, and the specific volume of finished bread is improved.)

1. A preparation method of a facultative charge chitosan degradation product is characterized by comprising the following steps: dissolving O-carboxymethyl chitosan in a phosphate buffer solution with the pH value of 5.5 to prepare a high-molecular aqueous solution; hydrolyzing the solution at 30-80 deg.C for 30-180 min, wherein the amount of chitosanase added into each gram of O-carboxymethyl chitosan is 50 enzyme activity units; after the reaction is finished, heating the mixture for 5 to 10 minutes by using a 120 ℃ oil bath, and inactivating enzyme to obtain the amphoteric charge chitosan degradation product.

2. The method of claim 1, wherein the degradation product of amphoteric charged chitosan is prepared by the following steps: the substitution degree of the O-carboxymethyl chitosan for enzymolysis is between 0.5 and 0.9, the O-carboxymethyl chitosan is dissolved in a phosphate buffer solution to be prepared into a high-molecular aqueous solution with the solid content concentration of 1 percent and the viscosity of 200-500m.Pa, and the viscosity of the product obtained after enzymolysis is between 20 and 80 mPa.S.

3. The use of the product of claim 1 as a frozen dough conditioner, wherein said frozen dough conditioner comprises: the preparation method comprises the step of adding the amphoteric charge chitosan degradation product prepared by the preparation method into flour for preparing frozen dough, wherein the addition amount is 0.2-0.8%.

4. The use of the product of claim 3 as a frozen dough conditioner, wherein said frozen dough conditioner comprises: the addition amount is 0.4 percent of the mass of the flour.

Technical Field

The invention belongs to the field of food additives, and particularly relates to a preparation method of a facultative charge chitosan degradation product and application of the product as a frozen dough modifier.

Background

With the popularization of processing and transportation modes such as 'central kitchen', 'cold chain distribution', etc. in the food field, the frozen dough technology has been widely applied by the production and retail enterprises of dough products. The frozen dough technology is that the kneaded dough is quickly frozen, formed, subpackaged and stored, and transported to a retail terminal as required for subsequent processing. It can reduce the labor cost in the production process, reduce the loss of raw materials and improve the stability of the quality of dough. However, moisture in the dough is easily recrystallized during the freezing process, the structure of the mucedin is damaged, the free thiol content of the mucedin is increased, and finally the quality deterioration problems such as cracking and hardening of the dough are caused.

At present, the formula of the antifreeze agent used commercially mainly comprises pyrophosphate, trehalose or a sugar salt mixture and the like, the addition amount is about 1%, however, the antifreeze agent can affect the taste of food in the using process, improve the calorific value of the food and is not beneficial to the mass eating of people with hyperglycemia and hypertension.

Patent application publication No. CN 108835159A discloses a method for improving frost cracking and surface hardening of frozen dough by using freeze-resistant polyperficial giant silkworm, and forming a compound with gum, sucrose, monopalmitate, transglutaminase, xylanase, whole egg liquid, lecithin and short-chain inulin. However, the antifreeze polypeptide related by the method has higher cost, more formula types and complex proportion.

In recent years there has been an increasing report of the use of food hydrocolloids as frozen dough protectants. The charge effect and hydrophilic character of polysaccharides are key to improving the freezing quality of dough. Negatively charged polysaccharides such as xanthan gum, carrageenan, sodium carboxymethylcellulose, and the like are widely used. For example, patent application publication No. CN 107041399 a discloses the use of sodium carboxymethylcellulose in frozen dough steamed products. The method can improve water holding capacity of dough in freezing process, inhibit retrogradation of starch, and improve edible quality of steamed bread.

Compared with the negatively charged carboxylated uronic acid, such as carboxymethyl starch, carboxymethyl cellulose and the like, the facultative charged polysaccharide has the structure with both positive and negative charges, can form stronger hydrogen bond action with water molecules, and improves the bound water content in the system. The hydrophilicity of the facultative charge structure is closely related to factors such as charge density and molecular weight. However, no frozen dough conditioner using a polysaccharide having an amphoteric charge as a raw material has been reported so far.

Carboxymethyl chitosan is a polysaccharide derivative having both amino and carboxyl groups. In industrial production, the carboxymethylation of chitosan is more mature and safer and the cost is easy to control compared with other modification modes. Therefore, the charge characteristic and the molecular weight of the carboxymethyl chitosan are screened, and the prepared amphoteric charge polysaccharide with high performance and low addition amount has important value for being used as a frozen dough improver.

Disclosure of Invention

The invention aims to provide a degradation product of facultative charge polysaccharide as a frozen dough modifier, which can stabilize the molecular structure of frozen dough, improve the processing performance, improve the specific volume and the mouthfeel of finished bread and prepare high-quality baked food at a lower addition amount.

The technical scheme adopted for solving the problems in the prior art is as follows:

a preparation method of a facultative charge chitosan degradation product comprises the following steps: dissolving O-carboxymethyl chitosan in a phosphate buffer solution with the pH value of 5.5 to prepare a high-molecular aqueous solution; hydrolyzing the solution at 30-80 deg.C for 30-180 min, wherein the amount of chitosanase added into each gram of O-carboxymethyl chitosan is 50 enzyme activity units; after the reaction is finished, heating the mixture for 5 to 10 minutes by using a 120 ℃ oil bath, and inactivating enzyme to obtain the amphoteric charge chitosan degradation product.

The amphoteric charge chitosan degradation product prepared by the method is added into flour for preparing frozen dough, and the addition amount is 0.2-0.8%.

Preferably, the addition amount is 0.4% of the mass of the flour.

Commercial carboxymethyl chitosan has different degrees of carboxylation substitution, and the molecular weight and viscosity of carboxymethyl chitosan can be adjusted by controlling enzymolysis time. The substitution degree of the O-carboxymethyl chitosan for enzymolysis is between 0.5 and 0.9, the O-carboxymethyl chitosan is dissolved in a phosphate buffer solution to be prepared into a high-molecular aqueous solution with the solid content concentration of 1 percent and the viscosity of 200-500m.Pa, and the viscosity of the product obtained after enzymolysis is between 20 and 80 mPa.S.

And (3) after the dough added with the modifying agent is pressed, preparing, cutting, forming and freezing to obtain the frozen dough. The later-stage processing method of the frozen dough comprises the steps of unfreezing, proofing and baking the frozen dough. The thawing temperature is 20-30 deg.C, 30 min. The fermentation time is 30-40 ℃ and 70 minutes, and the baking condition is 170-190 ℃ and 10-15 minutes.

The invention has the following advantages:

the degradation product of the facultative charge polysaccharide provided by the method is used as a frozen dough modifier, so that the size of ice crystals can be reduced, the degradation of mucedin is inhibited, the retrogradation of starch is reduced, and the specific volume of finished bread is improved.

The degradation product of the facultative charge polysaccharide provided by the invention is used as a frozen dough modifier for preparing frozen dough, and the prepared frozen dough has soft and delicate mouthfeel, is easy to swallow, and has large volume, smooth surface and uniform color. Meanwhile, the formula is simple and convenient, and the price is low.

Detailed Description

The technical scheme of the invention is further specifically described by the following embodiments: the raw material formula of the following examples is 100g of wheat flour, 50g of water, 1g of baking powder, 5g of butter, 8g of white granulated sugar and 1g of salt as basic formula, and the facultative charge polysaccharide degradation product prepared by the method of the invention is added as a frozen dough modifier before dough kneading, and the concentration is 0.4%. The preparation process flow is as follows: preparing materials, kneading dough, forming in blocks, loading into a tray, quickly freezing, refrigerating, unfreezing, fermenting, baking, cooling and packaging.

The blank control was prepared as follows:

uniformly mixing 100g of wheat flour, 50g of water, 1g of baking powder, 5g of butter, 8g of white granulated sugar and 1g of salt, and then kneading until the surface is smooth. After blending, blocking, forming, freezing at-30 deg.C for 5 hr, and refrigerating at-20 deg.C. Before baking, the frozen dough was thawed at room temperature for 30 minutes and allowed to proof for 70 minutes. Baking at 195 deg.C for 15 min to obtain bread.

Example 1

The preparation method of the frozen dough improver comprises the following steps: o-carboxymethyl chitosan with a degree of substitution of 0.5 was added to a phosphate buffer solution with pH 5.5 to prepare an aqueous solution with a solid content of 1% and a viscosity of 200 m.Pa. Hydrolyzing the solution at 50 deg.C for 60 min, wherein the amount of chitosanase added per gram of O-carboxymethyl chitosan is 50 enzyme activity units. After the reaction is finished, heating the mixture by using an oil bath at 120 ℃ for 10 minutes, and inactivating enzyme to obtain the amphoteric charge chitosan degradation product with the viscosity of 40 mPa.S. The product is mixed with flour ingredients, and the addition amount of the product is 0.4% of the mass of the flour. After blending, blocking, forming, freezing at-30 deg.C for 5 hr, and refrigerating at-20 deg.C. Before baking, the frozen dough was thawed at room temperature for 30 minutes and allowed to proof for 70 minutes. Baking at 195 deg.C for 15 min to obtain bread.

Example 2

The preparation method of the frozen dough improver comprises the following steps: o-carboxymethyl chitosan with a degree of substitution of 0.7 was added to a phosphate buffer solution with pH 5.5 to prepare an aqueous solution with a solid content of 1% and a viscosity of 300 m.Pa. Hydrolyzing the solution at 50 deg.C for 60 min, wherein the amount of chitosanase added per gram of O-carboxymethyl chitosan is 50 enzyme activity units. After the reaction is finished, heating the mixture by using an oil bath at 120 ℃ for 10 minutes, and inactivating enzyme to obtain the amphoteric charge chitosan degradation product with the viscosity of 50 mPa.S. The product is mixed with flour ingredients, and the addition amount of the product is 0.4% of the mass of the flour. After blending, blocking, forming, freezing at-30 deg.C for 5 hr, and refrigerating at-20 deg.C. Before baking, the frozen dough was thawed at room temperature for 30 minutes and allowed to proof for 70 minutes. Baking at 195 deg.C for 15 min to obtain bread.

Example 3

The preparation method of the frozen dough improver comprises the following steps: o-carboxymethyl chitosan with a degree of substitution of 0.9 was added to a phosphate buffer solution with pH 5.5 to prepare an aqueous solution with a solid content of 1% and a viscosity of 500 m.Pa. Hydrolyzing the solution at 50 deg.C for 60 min, wherein the amount of chitosanase added per gram of O-carboxymethyl chitosan is 50 enzyme activity units. After the reaction is finished, heating the mixture by using an oil bath at 120 ℃ for 10 minutes, and inactivating enzyme to obtain the amphoteric charge chitosan degradation product with the viscosity of 80 mPa.S. The product is mixed with flour ingredients, and the addition amount of the product is 0.4% of the mass of the flour. After blending, blocking, forming, freezing at-30 deg.C for 5 hr, and refrigerating at-20 deg.C. Before baking, the frozen dough was thawed at room temperature for 30 minutes and allowed to proof for 70 minutes. Baking at 195 deg.C for 15 min to obtain bread.

Example 4

The preparation method of the frozen dough improver comprises the following steps: o-carboxymethyl chitosan with a degree of substitution of 0.9 was added to a phosphate buffer solution with pH 5.5 to prepare an aqueous solution with a solid content of 1% and a viscosity of 500 m.Pa. Hydrolyzing the solution at 50 deg.C for 120 min, wherein the amount of chitosanase added per gram of O-carboxymethyl chitosan is 50 enzyme activity units. After the reaction is finished, heating the mixture by using an oil bath at 120 ℃ for 10 minutes, and inactivating enzyme to obtain the amphoteric charge chitosan degradation product with the viscosity of 20 mPa.S. The product is mixed with flour ingredients, and the addition amount of the product is 0.4% of the mass of the flour. After blending, blocking, forming, freezing at-30 deg.C for 5 hr, and refrigerating at-20 deg.C. Before baking, the frozen dough was thawed at room temperature for 30 minutes and allowed to proof for 70 minutes. Baking at 195 deg.C for 15 min to obtain bread.

The sensory quality was evaluated in the form of a score, the total score was 100, the score criteria are shown in table 1, and higher scores indicate better sensory quality. The reduction in bread firmness indicates an improvement in starch retrogradation during freezing. The quality of the finished bread is influenced by the amount of freezable water and the amount of gluten free sulphydryl in the dough. The ice crystal particles formed in the frozen dough are smaller when the content of the freezable water is low, which is beneficial to protecting the macromolecular network structure of the dough, reducing the damage of disulfide bonds in the gluten protein during frozen storage and improving the eating quality such as specific volume, elasticity and the like of the bread. The blank was bread made without the addition of the freeze modifier.

TABLE 1 bread sensory Scoring standards

TABLE 2 dough and bread product index parameters for 30 days of freezing

In comparative examples 1-3 (Table 2), the higher the carboxymethylation level of chitosan under the same enzymatic hydrolysis conditions, the lower the freezable water content of the frozen dough, and the less the ice crystals damage the disulfide bond structure of the gluten proteins, as indicated by a decrease in the free thiol content of the gluten proteins. The obtained bread has improved sensory score and bread specific volume by 36.7%.

Comparing the blank with examples 3-4 (table 2), the higher the enzymatic hydrolysis degree of carboxymethyl chitosan, the lower the viscosity, the less the freezable water of the frozen dough, and the lower the free thiol content of the gluten protein, and the improved bread quality, under the same substitution degree conditions.

By the method, the bread processed by the frozen dough modifier has good elasticity, uniform surface color and no crack, and the bread core structure is soft. Meanwhile, the bread specific volume is increased, and the content of the water which can be frozen is reduced, so that the frozen dough improver can inhibit the deterioration of the quality of dough in the freezing process and prolong the shelf life of the dough.

The protective scope of the present invention is not limited to the above-described embodiments, and it is apparent that various modifications and variations can be made to the present invention by those skilled in the art without departing from the scope and spirit of the present invention. It is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.