阅读说明：本技术 一种快速改善乳清分离蛋白质功能性质的简易方法 (Simple method for rapidly improving functional property of whey protein isolate ) 是由 白春清 郭扬凯 陈丽丽 赵利 刘雪梅 王寅 于 2021-02-05 设计创作，主要内容包括：本发明公开了一种快速改善乳清分离蛋白质功能性质的简易方法,该方法的操作步骤：乳清分离蛋白加水溶解,加入乳糖,搅拌混匀,调整pH,微波加热,取出冷却,冷冻干燥,得改性乳清分离蛋白。本方法相对于传统方法而言,生产周期大大缩短,且工艺简单、成本低廉,具有较高的推广价值。本方法所制备的改性乳清分离蛋白兼具较高的乳化性和抗氧化活性,可大大拓展乳清分离蛋白的应用范围。(The invention discloses a simple method for rapidly improving functional properties of whey protein isolate, which comprises the following operation steps: dissolving whey protein isolate in water, adding lactose, stirring, adjusting pH, microwave heating, cooling, and freeze drying to obtain modified whey protein isolate. Compared with the traditional method, the method has the advantages of greatly shortened production period, simple process, low cost and higher popularization value. The modified whey protein isolate prepared by the method has higher emulsibility and antioxidant activity, and the application range of the whey protein isolate can be greatly expanded.)

1. A simple method for rapidly improving the functional properties of whey protein isolate, characterized in that: the method comprises the following steps:

(1) preparing a solution: dissolving whey protein isolate in water to prepare whey protein isolate solution;

(2) adding lactose: weighing lactose in a certain proportion, adding the lactose into the whey protein isolate solution, and stirring until the lactose is fully dissolved to obtain a lactose-whey protein isolate mixed solution;

(3) adjusting the pH value: dropwise adding a sodium hydroxide solution and a hydrochloric acid solution into the lactose-whey protein isolate mixed solution to ensure that the pH value of the lactose-whey protein isolate mixed solution is 8.5;

(4) microwave heating: heating the lactose-whey protein isolate mixed solution with the pH value of 8.5 by microwave for a period of time;

(5) cooling the solution: immediately cooling the lactose-whey protein isolate mixed solution after microwave heating to obtain modified whey protein isolate reaction solution;

(6) and (3) freeze drying: and (3) freeze-drying the modified whey protein isolate reaction solution to obtain the modified whey protein isolate.

2. The simplified method for rapidly improving the functional properties of whey protein isolate as claimed in claim 1, wherein: the water in the step (1) is distilled water or water meeting the national sanitary standard for drinking water GB 5749-2006.

3. The simplified method for rapidly improving the functional properties of whey protein isolate as claimed in claim 1, wherein: the mass concentration of the whey protein isolate solution in the step (1) is 1-5%.

4. The simplified method for rapidly improving the functional properties of whey protein isolate as claimed in claim 1, wherein: and (3) the mass ratio of the whey protein isolate to the lactose in the lactose-whey protein isolate mixed solution in the step (2) is 5: 5.

5. The simplified method for rapidly improving the functional properties of whey protein isolate as claimed in claim 1, wherein: and (3) the concentration of the sodium hydroxide solution in the step (3) is 1mol/L, 0.1mol/L or 0.01mol/L, the concentration of the hydrochloric acid solution is 1mol/L, 0.1mol/L or 0.01mol/L, and the total dropping amount of the sodium hydroxide solution and the hydrochloric acid solution is controlled not to exceed 1% of the volume of the lactose-whey protein isolate mixed solution.

6. The simplified method for rapidly improving the functional properties of whey protein isolate as claimed in claim 1, wherein: and (4) microwave heating power is 560W, and microwave heating time is 7 min.

7. The simplified method for rapidly improving the functional properties of whey protein isolate as claimed in claim 1, wherein: the immediate cooling of the step (5) means that the central temperature of the lactose-whey protein isolate mixed solution is reduced to 10 ℃ or below within 10 min.

8. The simplified method for rapidly improving the functional properties of whey protein isolate according to any of claims 1 to 7, wherein: the modified whey protein isolate prepared by the method is applied to an emulsification embedding system.

Technical Field

The invention relates to the technical field of health-care food and medicines, in particular to a simple method for quickly improving the functional property of whey protein isolate.

Background

Whey protein isolate is a natural protein, has rich nutrition, high digestion and utilization rate, and has the functional characteristics of good emulsibility, foamability, gel property and the like, and is widely applied to the fields of dairy products, baked foods and the like. However, some of the disadvantages of natural proteins, such as limited antioxidant properties, limit their further use in the food industry, in particular in emulsion embedding systems.

The introduction of other groups or the modification of the structure and conformation of proteins by means of modification methods to improve the physicochemical and functional properties of proteins is the main approach to solve the above problems. The Maillard reaction is one of the commonly used modification methods, which is based on a grafting reaction between the epsilon-amino group of the protein and the carbonyl group on the reducing end of the sugar molecule. The reaction is a natural common reaction, and can be spontaneously carried out by direct heating without any chemical reagent serving as a catalyst. The water-soluble sugar can be grafted to protein molecules through a Maillard reaction, so that the 'amphiphilic' surfactant efficiency of the protein is improved, and the emulsibility is improved; and some substances with stronger reducibility are generated in the reaction process, so that the antioxidant activity of the modified protein is improved.

The traditional methods for carrying out Maillard reaction modification on protein and sugar at home and abroad mainly comprise two methods: dry heat and wet heat. The dry heating method is that protein and sugar are dissolved in water according to a certain proportion, freeze drying is carried out after uniform dispersion, and the freeze-dried powder is placed in an environment with a certain temperature (lower than the protein denaturation temperature) and relative humidity for reaction for several days to more than ten days; the wet-heat method is generally a method in which a protein and a sugar are dissolved in a buffer solution having a selected pH value in a predetermined ratio, and the resulting solution is heated in a closed vessel for several hours to ten or more hours. Therefore, the traditional maillard modification methods are as follows: the dry heating method and the wet heating method have the defects of long reaction time, high energy consumption and the like.

The microwave heating is a novel heating technology, the action principle of the microwave heating is to convert microwave energy into heat energy through dipole molecule high-frequency reciprocating motion inside a heating body, the microwave heating has the advantages of high heating speed, small heat loss, convenience in operation, uniform heating and the like, the process time can be shortened, the production efficiency is improved, and the cost is reduced.

The microwave power, the microwave time, the pH, the mass ratio of protein-polysaccharide and the like are main factors influencing the Maillard modification, determine the reaction process and directly influence the conformation and functional characteristics of the modified protein. The moderate Maillard reaction is favorable for improving the water-oil balance of the protein and improving the emulsibility of the protein. But the reaction is excessive, the crosslinking degree of protein-sugar is increased, on one hand, the balance of amphipathy is destroyed, the interfacial activity is greatly reduced, and the emulsibility is reduced; on the other hand, protein produced by excessive reaction is cross-linked and aggregated to generate a certain amount of insoluble matter, which lowers the solubility of the system, lowers the solubility, and lowers the emulsifiability. Meanwhile, a series of complex products can be generated in the process of the Maillard reaction, and the types and the contents of intermediate products are different and the antioxidant activity is different if the reaction degrees are different. Therefore, how to reasonably control the reaction conditions under the microwave heating condition is the key to prepare the protein with high emulsibility and oxidation resistance. In view of this, the present invention provides a simple method for rapidly improving the functional properties of whey protein isolate.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a simple method for quickly improving the functional properties of whey protein isolate, which solves the following technical problems: (1) the existing method for modifying protein by the Maillard reaction needs too long reaction time and has lower production efficiency; (2) the existing whey protein isolate modification method has low production efficiency and high production cost; (3) the antioxidant activity of the existing whey protein isolate is limited and needs to be improved; (4) the existing whey protein isolate has unsatisfactory functional characteristics, and cannot have high emulsibility and antioxidant activity.

(II) technical scheme

The invention provides a simple method for quickly improving functional properties of whey protein isolate, and develops a simple method for quickly improving functional properties of whey protein isolate aiming at the defects of the existing protein modification technology, particularly the Maillard reaction modification technology. On one hand, the method can greatly shorten the production period of the Maillard reaction, simplify the process and reduce the cost; on the other hand, on the basis of reasonably controlling the reaction process, a modified product with high antioxidant activity and emulsibility is produced.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a simple method for rapidly improving the functional properties of whey protein isolate, comprising the steps of:

(1) preparing a solution: dissolving whey protein isolate in water to prepare whey protein isolate solution;

(2) adding lactose: weighing lactose in a certain proportion, adding the lactose into the whey protein isolate solution, and stirring until the lactose is fully dissolved to obtain a lactose-whey protein isolate mixed solution;

(3) adjusting the pH value: dropwise adding a sodium hydroxide solution and a hydrochloric acid solution into the lactose-whey protein isolate mixed solution to ensure that the pH value of the lactose-whey protein isolate mixed solution is 8.5;

(4) microwave heating: heating the lactose-whey protein isolate mixed solution with the pH value of 8.5 by microwave for a period of time;

(5) cooling the solution: immediately cooling the lactose-whey protein isolate mixed solution after microwave heating to obtain modified whey protein isolate reaction solution;

(6) and (3) freeze drying: and (3) freeze-drying the modified whey protein isolate reaction solution to obtain the modified whey protein isolate.

Preferably, the water in the step (1) is distilled water or water meeting the national sanitary standard for domestic drinking water GB 5749-2006.

Preferably, the mass concentration of the whey protein isolate solution in step (1) is 1-5%.

Preferably, the mass ratio of the whey protein isolate to the lactose in the lactose-whey protein isolate mixed solution of step (2) is 5: 5.

Preferably, the concentration of the sodium hydroxide solution in the step (3) is 1mol/L, 0.1mol/L or 0.01mol/L, the concentration of the hydrochloric acid solution is 1mol/L, 0.1mol/L or 0.01mol/L, and the total dropping amount of the sodium hydroxide solution and the hydrochloric acid solution is controlled not to exceed 1 percent of the volume of the mixed solution of the lactose and the whey protein isolate.

Preferably, the microwave heating power of step (4) is 560W, and the microwave heating time is 7 min.

Preferably, the step (5) of immediately cooling means that the central temperature of the lactose-whey protein isolate mixture solution is reduced to 10 ℃ or below within 10min, so as to achieve the purpose of rapidly terminating the reaction.

(III) advantageous effects

The invention provides a simple method for quickly improving the functional properties of whey protein isolate, which firstly carries out innovative improvement aiming at the defects of long reaction time and the like of the traditional Maillard modification method and introduces a microwave heating technology. The traditional heat conduction mode taking temperature gradient as the leading factor is replaced by the molecular vibration internal heating type rapid heating, so that the reaction rate is improved, the reaction time required for obtaining a target product is greatly shortened, and the production efficiency is improved.

In addition, the invention improves the modification process formula of the whey protein isolate, can realize the preparation of the whey protein isolate with high emulsibility and antioxidant activity by reasonably controlling the process of the Maillard reaction, ensures that a reaction system does not need to use buffer solution, simplifies the production process and reduces the production cost.

Under the guidance of the technical idea, the invention optimizes important parameters such as microwave power, microwave time, pH, lactose-whey protein isolate mass ratio and the like, greatly shortens the time required by the traditional Maillard reaction, and reduces the time required by the wet reaction from several hours to dozens of hours to 7 minutes.

In addition, the modified whey protein isolate prepared by the method greatly improves the antioxidant activity on the basis of ensuring the high emulsibility of the modified whey protein isolate, and expands the application of the whey protein in an emulsification embedding system and other fields.

Drawings

FIG. 1 is a graph showing the effect of different microwave heating power and time on the emulsion stability of modified whey protein isolate;

FIG. 2 is a graph showing the effect of different microwave heating power and time on the emulsifying activity of modified whey protein isolate;

FIG. 3 is a graph showing the effect of different microwave heating power and time on DPPH radical clearance of modified whey protein isolate;

FIG. 4 is a graph of the effect of whey protein isolate to lactose mass ratio on the emulsion stability of modified whey protein isolate;

FIG. 5 is a graph of the effect of whey protein isolate to lactose mass ratio on the emulsifying activity of modified whey protein isolate;

figure 6 is a graph of the effect of whey protein isolate to lactose mass ratio on DPPH radical clearance of modified whey protein isolate.

Detailed Description

For further understanding of the present invention, the following examples are provided to illustrate a simple method for rapidly improving the functional properties of whey protein isolate, and the preparation method and application thereof, and the scope of the present invention is not limited by the following examples.

Example 1:

preparation of lactose-whey protein isolate mixed solution:

weighing 25g of whey protein isolate, adding 500mL of distilled water to fully dissolve the whey protein isolate to obtain a whey protein isolate solution, weighing 25g of lactose to the whey protein isolate solution, stirring the solution until the lactose is fully dissolved, and adjusting the pH value to 8.5 by using 1mol/L sodium hydroxide and 1mol/L hydrochloric acid to obtain a lactose-whey protein isolate mixed solution.

Example 2:

optimization of parameters of the microwave heating lactose-whey protein isolate mixed solution:

(1)560W microwave heating: 9 parts of the lactose-whey protein isolate mixture solution having a pH of 8.5 prepared in example 1 were taken and placed in a microwave oven at a microwave heating power of 560W for 10mL of each 10mL, and then microwave-heated for 0, 1, 3, 5, 7, 9, 11, 13, and 15min, and immediately taken out, cooled to 10 ℃ or less with ice water for 10min to obtain a modified whey protein isolate reaction solution, and the modified whey protein isolate reaction solution was freeze-dried to obtain 9 parts of modified whey protein isolate.

(2)320W microwave heating: 9 parts of the lactose-whey protein isolate mixture solution having a pH of 8.5 prepared in example 1 were taken and placed in a microwave oven at a microwave heating power of 320W for 10mL of each 10mL, and then heated for 0, 1, 3, 5, 7, 9, 11, 13, and 15min, and immediately taken out, cooled to 10 ℃ or less with ice water for 10min to obtain a modified whey protein isolate reaction solution, and the modified whey protein isolate reaction solution was freeze-dried to obtain 9 parts of modified whey protein isolate.

The Emulsion Stability (ESI), Emulsion Activity (EAI) and DPPH radical scavenging ratio of 9 parts of modified whey protein isolate with 560W microwave heating power and 9 parts of modified whey protein isolate with 320W microwave heating power were measured. The results are shown in fig. 1, fig. 2 and fig. 3, and it can be seen that the modified whey protein isolate prepared by the present invention has the best emulsification performance and strong antioxidant activity when the reaction conditions are microwave power 560W and microwave time 7 min.

Example 3:

determination of the optimal mass ratio of lactose to whey protein isolate:

weighing 6 parts of 0.5g of whey protein isolate respectively, adding 10mL of distilled water to fully dissolve the whey protein isolate respectively to obtain whey protein isolate solutions, weighing lactose into the whey protein isolate solutions according to the mass ratio of whey protein isolate to lactose being 5:3, 5:4, 5:5, 5:6, 5:7 and 5:8 respectively, stirring the whey protein isolate solutions until the whey protein isolate solutions are fully dissolved, adjusting the pH value to 8.5 by using 0.01mol/L sodium hydroxide and 0.01mol/L hydrochloric acid to obtain lactose-whey protein isolate mixed solutions, placing the lactose-whey protein mixed solutions into a microwave oven, heating the lactose-whey protein isolate solutions for 7min under 560W power, immediately taking the lactose-whey protein mixed solutions out, cooling the lactose-whey protein mixed solutions to 10 ℃ or below by using ice water to obtain modified whey protein isolate reaction solutions, and freeze-drying the modified whey protein isolate reaction solutions to obtain.

The Emulsion Stability (ESI), Emulsion Activity (EAI) and DPPH free radical scavenging rate were determined for 6 parts of modified whey protein isolates prepared at different lactose-whey protein mass ratios. As shown in fig. 4, 5 and 6, it can be seen that the modified whey protein isolate prepared according to the present invention has the best emulsification properties and strong antioxidant activity when the lactose-whey protein isolate mass ratio is 5: 5.

Example 4:

weighing whey protein isolate 0.2g, adding 20mL distilled water, dissolving completely to obtain whey protein isolate solution, weighing lactose 0.2g to whey fractionStirring to dissolve completely, adjusting pH to 8.5 with 0.01mol/L sodium hydroxide and 0.01mol/L hydrochloric acid to obtain lactose-whey protein isolate mixed solution, placing in microwave oven, heating with 560W power for 7min, immediately taking out, cooling with ice water to 10 deg.C or below in 10min to obtain modified whey protein isolate reaction solution, freeze drying the modified whey protein isolate reaction solution to obtain modified whey protein isolate, measuring the emulsion stability of the modified whey protein isolate to 87min and the emulsion activity to 0.35m²The DPPH radical clearance is 7.1%.

Example 5:

weighing 10g of whey protein isolate, adding 300mL of distilled water to fully dissolve to obtain a whey protein isolate solution, weighing 10g of lactose into the whey protein isolate solution, stirring to fully dissolve, adjusting the pH to 8.5 by using 1mol/L sodium hydroxide and 1mol/L hydrochloric acid to obtain a lactose-whey protein isolate mixed solution, placing the lactose-whey protein isolate mixed solution into a microwave oven, heating the lactose-whey protein isolate mixed solution for 7min under 560W power, immediately taking out the lactose-whey protein isolate mixed solution, cooling the whey protein separated solution to 10 ℃ or below by using ice water within 10min to obtain a modified whey protein isolate reaction solution, freeze-drying the modified whey protein isolate reaction solution to obtain modified whey protein isolate, measuring the emulsion stability of the modified whey protein isolate to be 85min and the emulsion activity to be 0.34m²The DPPH radical clearance is 7.5%.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.