Method for improving foam characteristics of vegetable protein

Abstract

The invention relates to the technical field of protein modification, in particular to a method for improving foam characteristics of vegetable protein. The method comprises the following steps: adding vegetable protein into water, stirring and hydrating to obtain vegetable protein dispersion liquid; the pH value of the vegetable protein dispersion liquid is adjusted, subcritical water treatment is carried out, and then shearing and homogenizing are carried out. The plant protein is modified by combining subcritical water treatment with pH regulation treatment, so that the foaming capacity of the plant protein is improved, the foam density is reduced, the expansion rate and porosity of the plant protein are improved, and the method has potential application value in foam type food.

Description

Technical Field

[0001] The invention relates to the technical field of protein modification, and in particular to a method for improving the foam properties of plant protein. Background Art

[0002] Protein foam is the main component of foam-type foods. In foam-type foods such as cakes, desserts, and ice cream, egg white protein and whey protein are the most widely used protein foaming agents, but their supply is often disturbed by food safety issues such as avian influenza and is not very stable. Plant protein has high nutritional value, low price, stable supply, and many good functional properties. However, the foaming ability and foam stability of natural plant protein are often not ideal and cannot meet the needs of practical applications. Therefore, a method to improve the foam properties of plant protein in a simple and low-cost way is of great value. Summary of the invention

[0003] The invention provides a method for improving the foam property of plant protein, which is used to solve the problem that the foaming ability and foam stability of existing natural plant protein are not ideal.

[0004] According to a first aspect of the present invention, the present invention provides a method for improving the foam properties of plant protein, the method comprising adding plant protein to water, stirring and hydrating to obtain a plant protein dispersion; adjusting the pH value of the plant protein dispersion, performing subcritical water treatment, and then shearing and homogenizing.

[0005] The pH adjustment technology is simple and efficient to operate. Through pH adjustment, plant protein can form a molten ball state that is not completely denatured. The stretching of the tertiary structure of the protein promotes the change of the hydrophilicity of the protein, which may improve the solubility, foaming ability and emulsification ability of the protein. Subcritical water refers to liquid water with a temperature lower than the critical pressure (Pc=22.1MPa) and critical temperature (Tc=374℃) and higher than 100℃; it has physical and chemical properties such as low viscosity, low density, low dielectric constant and high ionization constant, and also has the advantages of high efficiency, non-toxicity, recycling and low pollution. Subcritical water treatment is to use subcritical water to heat a plant protein dispersion with a suitable pH value. The present invention modifies the plant protein through subcritical water treatment combined with pH adjustment treatment, improves the foaming ability of the plant protein, reduces the foam density, and increases its expansion rate and porosity, which has potential application value in foam-type foods.

[0006] Furthermore, the pH value is 2.0-6.0 or 8.0-12.0. Experiments have found that adjusting the pH value to 2.0-6.0 or 8.0-12.0, combined with subcritical water treatment technology, can effectively improve the foam properties of plant protein such as foaming ability and foam stability. In some specific embodiments, the pH value is 3.0-5.0. In other specific embodiments, the pH value is 9.0-11.0.

[0007] Furthermore, the pH value is 8.0-12.0, preferably 9.0-11.0. Experiments further found that under the condition of pH value of 8.0-12.0, the improvement of the foam performance of plant protein is more obvious than that under the condition of pH value of 2.0-6.0. In addition, if the pH value is too high, the effect of improving the foam performance of plant protein cannot be achieved; if the pH value is too high, poor color and flavor will be produced, and the nutritional value will be reduced.

[0008] Furthermore, the subcritical water treatment conditions are: temperature of 110-135°C and time of 10-45min. By limiting the temperature and time of subcritical water treatment within a reasonable range, the adsorption rate and adsorption strength of subcritical water treated vegetable protein on the air / water interface can be significantly higher than those of conventional heat treated soy protein, which may be related to its more flexible molecular conformation, thereby improving the foam properties of protein such as foaming ability and foam stability.

[0009] Preferably, the subcritical water treatment conditions are: temperature of 125-135° C., time of 20-40 min. In some specific embodiments, the temperature is 130° C., time of 30 min.

[0010] Further, the plant protein is selected from one or two of soybean protein, mung bean protein and peanut protein. In some specific embodiments, the plant protein is selected from soybean protein or mung bean protein, preferably mung bean protein.

[0011] Furthermore, the mass concentration of the plant protein dispersion is 5%-8%.

[0012] Optionally, the mass concentration of the vegetable protein dispersion can be 5%, 5.5%, 6%, 6.5%, 7%, 7.5% or 8%, etc., and of course, it can also be other values ​​within the above range, which is not limited here, preferably 5-7%. In some specific embodiments, the mass concentration of the vegetable protein dispersion is 6%.

[0013] Further, the stirring time of the stirring and hydrating is 1-3h, and the hydration time is 8-18h. Preferably, the stirring time of the stirring and hydrating is 1.5-2.5h, and the hydration time is 10-14h. In some specific embodiments, the stirring time of the stirring and hydrating is 2h, and the hydration time is 12h. The stirring and hydrating time is an important factor affecting the performance of the plant protein dispersion. It affects the solubility of the protein, the stability of the dispersion and the functional properties of the protein, thereby affecting the application effect of the plant protein in food processing. Therefore, in practical applications, it is necessary to optimize the stirring and hydrating time to obtain the best protein performance according to the specific plant protein type and the expected application effect.

[0014] Further, the hydration temperature is 3-5°C. The hydration temperature has many effects on the plant protein dispersion, including the solubility, structure, functional properties, thermal stability, and aggregation and dispersion state of the protein. By selecting a hydration temperature within a reasonable range, the performance of the plant protein dispersion can be optimized. In some specific embodiments, the hydration temperature is 4°C.

[0015] Further, the shearing speed is 8000-12000 r / min, and the time is 30-120s. Preferably, the shearing speed is 9000-11000 r / min, and the time is 50-70s. In some specific embodiments, the shearing speed is 10000 r / min, and the time is 60s. By limiting the shearing speed and time within a reasonable range, it is beneficial for the vegetable protein to be fully dispersed in water.

[0016] Further, the homogenization pressure is 300-500 bar, and the number of times is 2-3 times. Preferably, the homogenization pressure is 400-500 bar. In some specific embodiments, the homogenization pressure is 500 bar, and the number of times is 3 times. By limiting the homogenization pressure and number of times within a reasonable range, it is beneficial to maintain the stability of the protein dispersion.

[0017] Furthermore, the foaming capacity of the vegetable protein treated by the method is 85-135%, and the foam density is 0.3-0.5 g / cm 3 The foam expansion rate is 89-170%, and the foam porosity is 47-63%.

[0018] Beneficial effects of the present invention: The invention provides a method for improving the foam properties of plant protein, wherein the plant protein is modified by subcritical water treatment combined with pH adjustment treatment, so as to improve the foaming ability of the plant protein, reduce the foam density, and increase the expansion rate and porosity thereof, and has potential application value in foam-type foods. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is a graph showing the foaming ability of the plant protein prepared in the examples of the present invention and the control sample.

[0021] Figure 2 It is a density diagram of the stable foam of the plant protein prepared in the embodiment of the present invention and the control sample.

[0022] Figure 3 This is a graph showing the expansion rate of the stable foam of the plant protein prepared in the embodiment of the present invention and the control sample.

[0023] Figure 4 The porosity diagram of the plant protein stable foam prepared in the embodiment of the present invention and the control sample. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1 This embodiment provides a method for improving the foam properties of vegetable protein, comprising the following steps: (1) Weigh 12 g of soy protein, add deionized water to 200 g, stir for 2 h, and then hydrate at 4 °C for 12 h to make it evenly dispersed to obtain a soy protein dispersion.

[0026] (2) The pH value of the soybean protein dispersion prepared in step (1) was adjusted to 3.0 and magnetically stirred for 30 minutes.

[0027] (3) The soy protein dispersion after pH adjustment in step (2) was placed in a subcritical water generator, the temperature was set to 130° C., and the treatment was performed for 30 min.

[0028] (4) The protein solution treated in step (3) was subjected to high-speed shearing at 10,000 r / min for 1 min, and then high-pressure homogenization was performed at 500 bar for 3 times.

[0029] Example 2 This embodiment provides a method for improving the foam properties of vegetable protein, which is different from Embodiment 1 in that: In step (2), the pH value of the soybean protein dispersion was adjusted to 5.0, and the remaining conditions and steps were the same as those in Example 1.

[0030] Example 3 This embodiment provides a method for improving the foam properties of vegetable protein, which is different from Embodiment 1 in that: In step (2), the pH value of the soybean protein dispersion was adjusted to 9.0, and the remaining conditions and steps were the same as those in Example 1.

[0031] Example 4 This embodiment provides a method for improving the foam properties of vegetable protein, which is different from Embodiment 1 in that: In step (2), the pH value of the soybean protein dispersion was adjusted to 11.0, and the remaining conditions and steps were the same as those in Example 1.

[0032] Example 5 This embodiment provides a method for improving the foam properties of plant protein, which is different from Embodiment 1 in that: in step (1), the selected plant protein is mung bean protein, and the remaining conditions and steps are the same as those in Embodiment 1.

[0033] Example 6 This embodiment provides a method for improving the foam properties of plant protein, which is different from Embodiment 2 in that: in step (1), the selected plant protein is mung bean protein, and the remaining conditions and steps are the same as those in Embodiment 2.

[0034] Example 7 This embodiment provides a method for improving the foam properties of plant protein, which is different from Embodiment 3 in that: in step (1), the selected plant protein is mung bean protein, and the remaining conditions and steps are the same as those in Embodiment 3.

[0035] Example 8 This embodiment provides a method for improving the foam properties of plant protein, which is different from Embodiment 4 in that: in step (1), the selected plant protein is mung bean protein, and the remaining conditions and steps are the same as those of Embodiment 4.

[0036] Test example The soy protein and mung bean protein samples obtained in step (1) of Example 1 without pH adjustment treatment and subcritical water treatment were used as control sample 1 and control sample 2.

[0037] Take 10 ml of protein sample and high-speed shear it at 10000 r / min for 2 min, record its volume, record the volume of the foam after whipping, carefully pour the prepared foam into a plastic cup of a certain volume, smooth the surface, and then weigh it at room temperature.

[0038] .

[0039] .

[0040] .

[0041] .

[0042] Depend on Figure 1-4 It can be seen that the method for improving the foam properties of plant protein of the present invention can effectively improve the foaming ability of plant protein, reduce the foam density of plant protein foaming, and improve the foam expansion rate and foam porosity. The foaming ability of the plant protein treated by the method of the present invention is 85-135%, and the foam density of the foam is 0.3-0.5g / cm 3 The foam expansion rate is 89-170%, and the foam porosity is 47-63%. Especially under alkaline pH conditions, the foam performance is more significantly improved. Among them, the foam performance of Example 8 is the best, with a foaming capacity of 130.67% and a foam density of 0.338 g / cm 3 The foam expansion rate is 169.088%, and the foam porosity is 62.795%.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for improving the foam properties of vegetable protein, characterized in that: The method comprises the following steps: adding the vegetable protein into water, stirring and hydrating the water to obtain a vegetable protein dispersion; adjusting the pH value of the vegetable protein dispersion, performing a subcritical water treatment, and then shearing and homogenizing the dispersion.

2. The method according to claim 1, characterized in that The pH value is 2.0-6.0 or 8.0-12.

0.

3. The method according to claim 2, characterized in that The pH value is 8.0-12.0, preferably 9.0-11.

0.

4. The method according to any one of claims 1 to 3, characterized in that: The subcritical water treatment conditions are: temperature of 110-135° C. and time of 10-45 min.

5. The method according to any one of claims 1 to 4, characterized in that: The plant protein is selected from one or two of soybean protein, mung bean protein and peanut protein.

6. The method according to any one of claims 1 to 5, characterized in that: The mass concentration of the vegetable protein dispersion is 5%-8%.

7. The method according to any one of claims 1 to 6, characterized in that: The stirring time of the stirring hydration is 1-3 hours, and the hydration time is 8-18 hours.

8. The method according to any one of claims 1 to 7, characterized in that: The shearing speed is 8000-12000 r / min, and the time is 30-120 s.

9. The method according to any one of claims 1 to 8, characterized in that: The homogenization pressure is 300-500 bar, and the number of times is 2-3 times.

10. The method according to any one of claims 1 to 9, characterized in that: The foaming capacity of the vegetable protein treated by the method is 85-135%, and the foam density is 0.3-0.5g / cm 3 The foam expansion rate is 89-170%, and the foam porosity is 47-63%.

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