Modified pea protein and preparation method of high-stability beverage thereof

Abstract

The invention belongs to the field of food science and technology, and relates to modification of pea protein and a preparation method of a high-stability beverage of the pea protein, in particular to development of the high-stability pea protein beverage by modifying the pea protein through combined treatment of ball milling and high-pressure homogenization. The pea protein powder is selected as a raw material, optimal process parameters for modifying the pea protein through combination of ball milling and high-pressure homogenization are established, and the high-concentration and high-stability pea protein beverage is prepared.

Description

Technical Field

[0001] The present invention belongs to the field of food science and technology, and relates to a method for modifying pea protein and the preparation of a highly stable beverage therefrom. Background Art

[0002] Plant-based protein beverages refer to protein beverages derived from plant sources, providing options for people with lactose intolerance or milk protein allergies, as well as those who adhere to a vegan or vegetarian diet. In recent years, with the rapid expansion of the plant-based protein beverage market, various types of protein beverages, including almond, soy, oat, and coconut, have emerged to meet consumer demands, with soy, nuts, and grains being the main components.

[0003] Peas are an edible leguminous crop containing 20%-25% protein and have received wide attention due to their high protein content. Pea protein belongs to high-quality plant protein with a balanced amino acid composition, supporting muscle growth and repair, and also having a digestive-promoting effect to help maintain intestinal health. In addition, due to its cholesterol-free, lactose-free, low allergenicity, and non-GMO characteristics, it is widely used in plant-based beverages. However, pea protein faces problems such as low solubility, low content of soluble protein, and poor stability in plant-based beverages. Therefore, it is necessary to modify pea protein in order to obtain a highly stable plant-based beverage. Summary of the Invention

[0004] The object of the present invention is to modify pea protein and prepare a highly stable beverage therefrom to solve the problems existing in the above prior art.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One technical solution of the present invention: A method for preparing a modified pea protein and a highly stable beverage therefrom.

[0007] (1) According to the mass ratio of pea protein powder to grinding balls of 1:8 (m / m), add pea protein powder and grinding balls into an alumina tank of a ball mill, and the mass ratio of large balls to small balls in the grinding balls is 1:7 (m / m). The ball mill is operated at a speed of 400 r / min for ball milling, with forward and reverse milling alternating every 30 min. After ball milling for 2-12 h, the pea protein powder modified by ball milling is obtained;

[0008] (2) The pea protein powder (1) modified by ball milling is dissolved in deionized water, and its pH is adjusted to 7.0 with 1 mol / L NaOH solution to prepare a 6% (w / v) pea protein solution. The solution is subjected to 3 cycles of treatment under a pressure of 40 - 150 MPa by a high-pressure homogenizer. Meanwhile, a condenser is connected to control the temperature during the high-pressure homogenization process at about 25 - 28 °C. The treated protein solution is freeze-dried to obtain the pea protein powder modified by combined ball milling and high-pressure homogenization;

[0009] (3) The pea protein powder (2) modified by combined ball milling and high-pressure homogenization is dissolved with deionized water to prepare a pea protein solution with a mass concentration of 2% - 8% (w / v). Subsequently, the prepared pea protein solution is heat-treated at 85 °C for 15 min to prepare high-stability pea protein beverages with different concentrations.

[0010] Further, the ball milling time is 8 h.

[0011] Further, the high-pressure homogenization pressure is 120 MPa.

[0012] Further, the pea protein solution with a mass concentration of 6% (w / v).

[0013] The second technical solution of the present invention: A high-stability pea protein beverage prepared by the above preparation method.

[0014] The present invention discloses the following technical effects:

[0015] (1) Ball milling combined with high-pressure homogenization can significantly improve the solubility and gel properties of pea protein. Compared with untreated pea protein, the particle size of pea protein treated by ball milling for 8 h and high-pressure homogenization at 120 MPa is reduced by 76.63%, and the solubility and gel strength are increased by 29.01% and 92.33% respectively;

[0016] (2) Under the treatment conditions of ball milling for 8 h combined with high-pressure homogenization at 120 MPa, a pea protein aqueous solution with a concentration of 4 - 6% (w / v) is prepared, which has good stability. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 Particle sizes of pea protein under different treatment conditions.

[0019] Figure 2 is the solubility of pea protein under different treatment conditions.

[0020] Figure 3 is the gel properties of pea protein under different treatment conditions.

[0021] Figure 4 is the particle size of pea protein after heat treatment under different concentration conditions.

[0022] Figure 5 is the soluble protein content of pea protein after heat treatment under different concentration conditions.

[0023] Figure 6 The solubility of pea protein after heat treatment under different concentration conditions.

[0024] Figure 7 is the stability index of pea protein after heat treatment under different concentration conditions.

[0025] Figure 8 is the storage stability of the aqueous solution of pea protein after heat treatment under different concentration conditions on the 0th day (A), 7th day (B), 14th day (C), and 21st day (D). Detailed implementation manners

[0026] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0027] It should be understood that the terms described in the present invention are only for describing particular implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0028] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0029] Without departing from the scope or spirit of the present invention, various modifications and variations can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of this application are merely exemplary.

[0030] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0031] Examples:

[0032] Example 1

[0033] According to the mass ratio of pea protein powder to grinding balls of 1:8 (m / m), pea protein powder and grinding balls were added to the alumina tank of the ball mill. The mass ratio of large balls to small balls in the grinding balls was 1:7 (m / m). The ball mill was ball-milled at a speed of 400 r / min, and the forward and reverse grinding were alternated every 30 min. After grinding for 8 h, the pea protein powder modified by ball milling was obtained;

[0034] (2) The pea protein powder (1) modified by ball milling was dissolved in ionized water, and 1 mol / L NaOH solution was used to adjust its pH to 7.0 to prepare a 6% (w / v) pea protein solution. It was subjected to 3 cycles of treatment under a pressure of 120 MPa by a high-pressure homogenizer, and at the same time, a condenser was connected to control the temperature during the high-pressure homogenization process to about 25 - 28 °C. The treated protein solution was freeze-dried to obtain the pea protein powder modified by ball milling combined with high-pressure homogenization;

[0035] (3) The pea protein powder (2) modified by ball milling combined with high-pressure homogenization was dissolved in deionized water to prepare a pea protein solution with a concentration of 6% (w / v); subsequently, the prepared pea protein solution was heat-treated at 85 °C for 15 min to prepare high-stability pea protein beverages with different concentrations.

[0036] Example 2

[0037] According to the mass ratio of pea protein powder to grinding balls of 1:8 (m / m), pea protein powder and grinding balls were added to the alumina tank of the ball mill. The mass ratio of large balls to small balls in the grinding balls was 1:7 (m / m). The ball mill was ball-milled at a speed of 400 r / min, and the forward and reverse grinding were alternated every 30 min. After grinding for 8 h, the pea protein powder modified by ball milling was obtained;

[0038] (2) The pea protein powder (1) modified by ball milling was dissolved in deionized water, and its pH was adjusted to 7.0 with 1 mol / L NaOH solution to prepare a 6% (w / v) pea protein solution. The solution was subjected to 3 cycles of treatment under a pressure of 120 MPa using a high-pressure homogenizer. Meanwhile, a condenser was connected to control the temperature during the high-pressure homogenization process at about 25 - 28 °C. The treated protein solution was freeze-dried to obtain the pea protein powder modified by combined ball milling and high-pressure homogenization;

[0039] (3) The pea protein powder (2) modified by combined ball milling and high-pressure homogenization was dissolved with deionized water to prepare a pea protein solution with a mass concentration of 4% (w / v). Subsequently, the prepared pea protein solution was heat-treated at 85 °C for 15 min, and then high-stability pea protein beverages with different concentrations were prepared.

[0040] Example 3

[0041] According to the mass ratio of pea protein powder to grinding balls of 1:8 (m / m), pea protein powder and grinding balls were added to an alumina tank of a ball mill. The mass ratio of large balls to small balls in the grinding balls was 1:7 (m / m). The ball mill was operated at a speed of 400 r / min for ball milling, and the forward and reverse grinding was alternated every 30 min. After 8 h of grinding, the pea protein powder modified by ball milling was obtained;

[0042] (2) The pea protein powder (1) modified by ball milling was dissolved in deionized water, and its pH was adjusted to 7.0 with 1 mol / L NaOH solution to prepare a 6% (w / v) pea protein solution. The solution was subjected to 3 cycles of treatment under a pressure of 120 MPa using a high-pressure homogenizer. Meanwhile, a condenser was connected to control the temperature during the high-pressure homogenization process at about 25 - 28 °C. The treated protein solution was freeze-dried to obtain the pea protein powder modified by combined ball milling and high-pressure homogenization;

[0043] (3) The pea protein powder (2) modified by combined ball milling and high-pressure homogenization was dissolved with deionized water to prepare a pea protein solution with a concentration of 8% (w / v). Subsequently, the prepared pea protein solution was heat-treated at 85 °C for 15 min, and then high-stability pea protein beverages with different concentrations were prepared.

[0044] Test Example 1

[0045] I. Particle size of modified pea protein

[0046] The particle size of pea protein was measured using a laser particle size distribution analyzer with dynamic light scattering technology. The pea protein powder was dissolved in water to prepare a 6% (w / v) pea protein solution. Before measurement, the sample was pre-diluted 100 times to avoid multiple scattering effects. Then the average particle size (D43 )。

[0047] Figure 1 The particle size of pea protein under different treatment conditions. Compared with single ball milling and single high-pressure homogenization, the particle size of pea protein treated by ball milling combined with high-pressure homogenization decreased significantly (P<0.05). Compared with the particle size of untreated pea protein, the particle size of pea protein after ball milling combined with high-pressure homogenization decreased significantly by 76.6%.

[0048] II. Solubility of Modified Pea Protein

[0049] Prepare a 6% (w / v) pea protein dispersion in deionized water. After complete dissolution, let it stand overnight at 4°C. Centrifuge the dispersion at 20°C and 8000×g for 20 min. Measure the solubility of pea protein. Mix 30 μL of the diluted supernatant with 150 μL of Coomassie Brilliant Blue G-250 staining solution, and measure the absorbance at 595 nm using an enzyme-linked immunosorbent assay reader. Use the BSA standard curve (y = 1.83778x + 0.5041, R2 = 0.9995, where x is the BSA concentration and y is A595) to measure the protein content in the supernatant, and calculate according to the following formula.

[0050]

[0051] Figure 2 The solubility of pea protein under different treatment conditions. Compared with the untreated group, ball milling, high-pressure homogenization, and ball milling combined with high-pressure homogenization significantly increased the solubility of pea protein (P<0.05). The solubility of the untreated group was 48.97±0.85%. Under the treatment conditions of ball milling for 8 h combined with high-pressure homogenization at 120 MPa, the solubility of pea protein reached the highest, which was 68.98±0.61% (P<0.05). After single ball milling for 8 h and single high-pressure homogenization at 120 MPa, the solubilities of pea protein were 56.31±0.54% and 61.22±0.8% respectively. Compared with them, the solubility of pea protein increased significantly under the treatment of ball milling for 8 h combined with high-pressure homogenization at 120 MPa.

[0052] III. Gel Strength of Modified Pea Protein

[0053] Figure 3 The gel strength of pea protein under different treatment conditions. Use a texture analyzer with a P / 0.5 probe at 25°C to measure the gel strength of pea protein prepared at a concentration of 20% (w / v). The trigger force is 3 g, and the speeds before measurement, during measurement, and after measurement are 5.0, 1.0, and 5.0 mm / s respectively. The maximum force when the probe is pressed down to 10 mm is defined as the gel strength.

[0054] Compared with the untreated group (7.24±0.25 g), the ball milling combined with high-pressure homogenization treatment significantly enhanced the strength of pea protein gel. Under the combined treatment of 8 h ball milling + 120 MPa, the gel strength was significantly increased to 94.4±0.53 g (P<0.05), which was the strongest among all treatment groups.

[0055] IV. Particle Size of High-Stability Protein Solution

[0056] The particle size of pea protein was measured using a laser particle size distribution analyzer by dynamic light scattering technology. Before measurement, the sample was pre-diluted 100 times to avoid multiple scattering effects. Then, the average particle size (D 50 ) of the protein sample was measured at 25 °C.

[0057] Figure 4 shows the particle size of pea protein after heat treatment under different concentration conditions. The research results show that under the untreated condition, the D 50 of different concentrations of pea protein aqueous solutions ranged from 1830 - 5045 nm, and there were significant differences among these 4 groups of samples (P<0.05). Under the combined treatment of 8 h + 120 MPa, the D 50 of 2% - 8% (w / v) different concentrations of pea protein aqueous solutions ranged from 280 nm to 320 nm. Compared with the untreated group, under the conditions of 8 h ball milling and 120 MPa high-pressure homogenization, the D 50 of 2% - 8% different concentrations of pea protein aqueous solutions was significantly reduced, showing higher stability.

[0058] V. Soluble Protein Content of High-Stability Protein Solution

[0059] The soluble protein content of each pea protein sample was determined with reference to the Bradford method. A 6% (w / v) protein solution was prepared, diluted 100 times, and a certain amount of Coomassie Brilliant Blue was added to measure its absorbance value. The soluble protein content in the pea protein sample was calculated according to the following formula.

[0060]

[0061] Figure 5 shows the soluble protein content of pea protein solutions after heat treatment under different concentration conditions. Compared with the untreated group, the combined treatment significantly increased the soluble protein content at each concentration (P<0.05); moreover, when the pea protein treated by ball milling combined with high-pressure homogenization (8 h + 120 MPa) was at a concentration of 4% - 6% (w / v), its soluble protein content was relatively high, about 60 - 65%.

[0062] VI. Solubility of High-Stability Protein Solution

[0063] Each concentration of pea protein solution was centrifuged at 20 °C and 8000×g for 20 min. The solubility of pea protein was measured. 30 μL of the diluted supernatant was mixed with 150 μL of Coomassie Brilliant Blue G-250 staining solution, and the absorbance at 595 nm was measured using a microplate reader. The protein content in the supernatant was measured using a BSA standard curve (y = 1.83778x + 0.5041, R 2 = 0.9995, where x is the BSA concentration and y is A595), and the calculation was performed according to the following formula.

[0064]

[0065] Figure 6 The solubility of heat-treated pea protein under different concentration conditions. In the untreated group, as the concentration of pea protein increased, the solubility decreased significantly, ranging from 50% to 63%, with the lowest solubility at 8% (w / v), only 50.43 ± 0.95%; the ball-milling combined with high-pressure homogenization (8 h + 120 MPa) treatment group also showed a trend of decreasing solubility with increasing concentration, with the solubility ranging from 60% to 70%, and the highest solubility at 2% (w / v), reaching 69.64 ± 0.76%. Compared with the untreated group, the ball-milling combined with high-pressure homogenization treatment significantly increased the solubility of pea protein at each concentration (P < 0.05), indicating that the ball-milling combined with high-pressure homogenization treatment can effectively improve the problem of decreased solubility under high-concentration conditions.

[0066] VII. Stability index of highly stable protein solution

[0067] The stability index of each concentration of pea protein solution was measured. After the pea protein solution was diluted with deionized water, it was centrifuged at 4000×g for 15 min, and the absorbance of the pea protein solution before centrifugation (A0) and the absorbance of the supernatant after centrifugation (A) at 625 nm were measured. According to the formula:

[0068]

[0069] Figure 7 is the stability index of heat-treated pea protein under different concentration conditions. In the untreated group, as the concentration of pea protein increased from 2% to 8% (w / v), the stability index gradually decreased, with the highest stability index at 2% concentration, which was 13.74 ± 0.46%; the ball-milling combined with high-pressure homogenization (8 h + 120 MPa) treatment group also showed a trend of decreasing stability index with increasing concentration, reaching the highest at 2% concentration, which was 37.02 ± 0.98%. Compared with the untreated group, the ball-milling combined with high-pressure homogenization treatment significantly increased the stability index at each concentration (P < 0.05). Among them, there was no significant difference in the stability index at 4% and 6% concentrations (P > 0.05), indicating that the protein system still had good stability at 6% concentration.

[0070] VIII. Storage stability of protein solution with high stability

[0071] The storage stability of pea protein aqueous solution after heat treatment under different concentration conditions was determined at the 0th day (A), 7th day (B), 14th day (C), and 21st day (D) according to the centrifugal precipitation rate of pea protein samples. Accurately weigh 10 g of the sample, centrifuge at 4000×g for 15 min, weigh the weight of the precipitate at the bottom of the centrifuge tube, and determine the centrifugal precipitation rate of the pea protein aqueous solution after heat treatment under different concentration conditions.

[0072]

[0073] Figure 8 Shown in the figure are the storage stabilities of pea protein aqueous solution after heat treatment under different concentration conditions at the 0th day (A), 7th day (B), 14th day (C), and 21st day (D). With the extension of storage time, from the 0th day to the 21st day, the centrifugal precipitation rate of the pea protein aqueous solution under different concentrations showed a gradually increasing trend, that is, the stability gradually decreased. Under the condition of the same storage time, compared with the untreated group, the stability of pea protein in the ball milling combined with high-pressure homogenization treatment group increased significantly. However, in order to enable pea protein to have better applications in the food industry, relatively high concentrations and high stabilities are required to prepare high-protein plant beverages using pea protein as a raw material. Under the combined treatment of ball milling for 8 h + 120 MPa of high-pressure homogenization, the centrifugal precipitation rates of the 6% (w / v) pea protein aqueous solution at the 0th day, 7th day, 14th day, and 21st day were 9.77±0.21%, 11.2±0.17%, 12.2±0.18%, and 14.2±0.15% respectively. Therefore, after the treatment of pea protein by ball milling for 8 h combined with high-pressure homogenization at 120 MPa, at a concentration of 6% (w / v), the pea protein aqueous solution can maintain good stability.

Claims

1. A preparation method of a modified pea protein and its highly stable drink, characterized in that the steps Including: (1) According to the mass ratio of pea protein powder to grinding balls being 1:8 (m / m), add pea protein powder and grinding balls into the alumina tank of the ball mill. The mass ratio of large balls to small balls in the grinding balls is 1:7 (m / m). The ball mill is ball-milled at a speed of 400 r / min, with forward and reverse grinding alternating every 30 min. After grinding for 2 - 12 h, the pea protein powder modified by ball milling is obtained; (2) The pea protein powder modified by ball milling (1) is dissolved in ionized water, and 1 mol / L NaOH solution is used to adjust its pH to 7.0 to make a 6% (w / v) pea protein solution. It is subjected to 3 cycles of treatment under a pressure of 40 - 150 MPa by a high-pressure homogenizer. At the same time, a condenser is connected to control the temperature during the high-pressure homogenization process at about 25 - 28 °C. The treated protein solution is freeze-dried to obtain the pea protein powder modified by ball milling combined with high-pressure homogenization; (3) The pea protein powder modified by ball milling combined with high-pressure homogenization (2) is dissolved with deionized water to make a pea protein solution with a concentration of 2% - 8% (w / v); Subsequently, the prepared pea protein solution is heat-treated at 85 °C for 15 min to prepare high-stability pea protein beverages with different concentrations.

2. The preparation method according to claim 1, characterized in that, The ball milling time is 8 h.

3. The preparation method according to claim 1, characterized in that, The high-pressure homogenization pressure is 120 MPa.

4. The preparation method according to claim 1, characterized in that, A pea protein solution with a concentration of 6% (w / v).

5. The modified pea protein and its high-stability beverage prepared by the preparation method according to any one of claims 1 - 4.

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