Modified chickpea protein isolate and method for preparing the same

Abstract

The application discloses modified chickpea protein isolate and a preparation method thereof, and belongs to the field of plant proteins. The preparation method of the modified chickpea protein isolate comprises the following steps: S1, removing chickpea skins, grinding the chickpeas into chickpea powder, and defatting the chickpea powder to obtain defatted chickpea powder; S2, dispersing the defatted chickpea powder in deionized water to extract chickpea protein isolate; and S3, performing plasma jet treatment on the chickpea protein isolate to obtain modified chickpea protein isolate. After the plasma jet treatment, the emulsifying property and the foaming property of the chickpea protein isolate are improved. Meanwhile, compared with traditional modification methods, the modified chickpea protein isolate prepared by the method provided by the application is safer and has no residues, and is suitable for the green, safe and efficient production of plant protein food.

Description

Technical Field

[0001] This invention relates to the field of plant protein, and more specifically, to a chickpea protein isolate and its modification method. Background Technology

[0002] Plant protein is an important source of dietary protein for humans, rich in nutrients and with fewer negative impacts on the environment and health. It is estimated that the consumption of plant-based protein will grow from US$29.4 billion in 2020 to US$162 billion by 2030. The increasing demand for innovation is driving the exploration of new protein sources. Chickpea protein isolate (CPI), as a type of plant protein, has advantages over traditional soy protein, such as higher yield, lower cost, and lower allergenicity, making it a promising ingredient beneficial for developing new health products. Chickpea seeds are considered a suitable source of dietary protein, possessing a good amino acid balance, high protein bioavailability, and relatively low levels of anti-nutritional factors. However, compared to animal proteins, plant proteins have poorer functional properties such as solubility, foaming properties, emulsification, digestibility, oil-holding capacity, and water-holding capacity, which limits their application in the food industry. Therefore, there is an urgent need to develop a method to enhance the functional properties of chickpea protein isolate. Summary of the Invention

[0003] The problem to be solved by this invention is how to improve the functional properties of chickpea protein isolate.

[0004] To address the above problems, the first aspect of this invention provides a method for preparing modified chickpea protein isolate, comprising the following steps:

[0005] S1: Remove the chickpea skins, grind the chickpeas into chickpea flour, defatt the chickpea flour to obtain defatted chickpea flour.

[0006] S2: Disperse defatted chickpea flour in deionized water to extract chickpea protein isolate;

[0007] S3: Chickpea protein isolate is subjected to plasma jet treatment to obtain modified chickpea protein isolate.

[0008] The chickpea protein isolate provided by this invention is prepared by plasma jet treatment. Plasma jet treatment can unfold the protein structure of chickpea protein isolate, expose more active sites, and thus enhance the interaction between chickpea protein isolate and water molecules to achieve the purpose of modification.

[0009] Preferably, step S3 specifically includes:

[0010] S31: Disperse chickpea protein isolate in a buffer solution with a pH of 6.5 to 7.5 to hydrate the chickpea protein isolate and form a hydrated chickpea protein isolate suspension with a protein concentration of 1% to 3%.

[0011] S32: At room temperature, the hydrated chickpea protein isolate suspension obtained in step S31 is subjected to plasma jet treatment to obtain modified chickpea protein isolate.

[0012] Preferably, when performing plasma jetting, the plasma jetting treatment time is 5 to 60 seconds.

[0013] Preferably, when performing plasma jetting, the distance between the plasma nozzle and the surface of the hydrated chickpea protein isolate suspension is 30–60 mm.

[0014] Preferably, when performing plasma jetting, the jet outlet flow rate is 20–50 L / min.

[0015] Preferably, step S2 specifically includes:

[0016] S21: Disperse defatted chickpea flour in deionized water, adjust the pH to 8.5-9, stir for 30-240 minutes, centrifuge, take the supernatant, resuspend the precipitate and repeat the extraction 1-3 times, mix the supernatant to obtain chickpea protein isolate solution;

[0017] S22: Adjust the pH of the crude extract obtained in step S22 to 4-5, centrifuge, and collect the precipitate;

[0018] S23: Redissolve the precipitate in water, adjust the pH to 7.0 to obtain a chickpea protein isolate suspension, and freeze-dry to obtain chickpea protein isolate powder.

[0019] Preferably, in step S1, chickpeas are ground into chickpea flour with a particle size of 1 to 15 μm.

[0020] Preferably, in step S1, hexane is used to defatt the chickpea flour.

[0021] Preferably, the mass-to-volume ratio of chickpea flour to n-hexane during the defatting process is 1:(2-6).

[0022] Furthermore, a second aspect of the present invention provides chickpea protein isolate prepared by the aforementioned method.

[0023] The beneficial effects of this invention are as follows: The modified chickpea protein isolate preparation method provided by this invention uses plasma jet treatment of chickpea protein isolate. Compared with traditional physical and chemical modification, the method provided by this invention is safer and leaves no residue. The chickpea protein isolate treated under specific conditions has better emulsifying and foaming properties, which can improve the quality of plant protein foods and is suitable for the green, safe and efficient production of plant protein foods. Attached Figure Description

[0024] Figure 1 The figure shows the foaming test results of modified chickpea protein isolate after receiving plasma jet treatment for different durations in Example 2 of the specific embodiment of the present invention;

[0025] Figure 2 The figure shows the emulsification test results of modified chickpea protein isolate after receiving plasma jet treatment for different durations in Example 2 of the specific embodiment of the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not intended to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the claims of the present invention.

[0027] It should be noted that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0028] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In some instances, terms having a conventional meaning are defined herein for clarification or ease of reference, and such definitions should not be construed as indicating a significant difference from conventional understanding in the art. The technical methods described or referenced herein are generally well understood by those skilled in the art and employed by conventional methods. Unless otherwise stated, the use of commercially available reagents and instruments shall be performed according to the manufacturer's instructions and parameters.

[0029] This invention provides a modified chickpea protein isolate and its preparation method. Specifically, the modified chickpea protein isolate is prepared by plasma jet treatment of chickpea protein isolate powder to improve its functional properties. Specifically, the modified chickpea protein isolate is obtained through the following steps:

[0030] S1: Remove the chickpea skins, grind the chickpeas into chickpea flour with a particle size of 1-15μm, defatt the chickpea flour with n-hexane to obtain defatted chickpea flour.

[0031] S21: Disperse defatted chickpea flour in deionized water, adjust the pH to 8.5-9 with sodium hydroxide, stir for 30-240 minutes, centrifuge, and take the supernatant to obtain chickpea protein isolate solution;

[0032] S22: Repeat step S21 0 to 3 times, and mix with the chickpea protein isolate obtained in step S21 to form a crude extract;

[0033] S23: Adjust the pH of the crude extract obtained in step S22 to 4-5 using hydrochloric acid, centrifuge, and collect the precipitate;

[0034] S24: The precipitate was redissolved in water and the pH was adjusted to 7.0 with sodium hydroxide to obtain a chickpea protein isolate suspension. After freeze-drying, chickpea protein isolate powder was obtained.

[0035] S31: Disperse chickpea protein isolate in a buffer solution with a pH of 6.5 to 7.5 to hydrate the chickpea protein isolate and form a hydrated chickpea protein isolate suspension with a protein concentration of 1% to 3%.

[0036] S32: The hydrated chickpea protein isolate suspension obtained in step S31 is subjected to plasma jet treatment at 0-10℃ to obtain modified chickpea protein isolate. The chickpea protein isolate provided by the specific embodiments of the present invention greatly improves its emulsifying and foaming properties.

[0037] Example 1

[0038] Preparation of modified chickpea protein isolate

[0039] Soak chickpeas in excess water overnight to remove the skins. Dry the peeled chickpeas at 60°C. Grind the dried chickpeas using a grinder and sieve the chickpea flour through an 80-mesh sieve. Mix the chickpea flour with n-hexane at a ratio of 1:4 (w / v) in a beaker and defatt the mixture by stirring at room temperature in a fume hood for 60 minutes. Air dry the mixture in a fume hood overnight to obtain defatted chickpea flour.

[0040] The defatted chickpea powder was dispersed in water, and the pH was adjusted to 9 with 1M NaOH. The mixture was stirred at room temperature for 2 hours, with the pH controlled at 9. After stirring, the mixture was centrifuged at 7000 rpm for 15 minutes. The supernatant was collected, and the precipitate was extracted again with water to ensure the purity of the crude extract. The supernatants from the two extractions were mixed, and the pH was adjusted to 4.5 with 1M HCl. The mixture was centrifuged at 7000 rpm for 15 minutes. The precipitate was collected and resuspended in distilled water. The pH was adjusted to 7.0 with NaOH, and the chickpea protein isolate precipitated, forming a suspension. The suspension was freeze-dried to obtain chickpea protein isolate powder.

[0041] Chickpea protein isolate powder was dispersed in 0.02M PBS (pH=7.0) buffer to prepare a 1% suspension. The suspension was stirred at room temperature for 2 hours to ensure complete hydration. The chickpea protein isolate suspension was cooled to room temperature and divided into 6 groups. The plasma nozzle was set at 40 mm above the liquid surface, and the flow rate of the jet outlet was adjusted to 30 L / min. The 6 groups of chickpea protein isolate suspensions were treated with plasma jet for 0s, 10s, 20s, 30s, 40s, and 50s respectively at 0-8℃. The suspensions were then allowed to stand at 4℃ for 12 hours to ensure complete reaction, thus obtaining modified chickpea protein isolate.

[0042] Example 2

[0043] Performance testing

[0044] The hydroxyl content, thiol content, and dityrosine content of the modified chickpea protein isolate prepared in Example 1 were determined using instruments, and the results are shown in Table 1.

[0045] Table 1. Effects of plasma jet treatment on the carbonyl, thiol, and dityrosine content in chickpea protein isolate.

[0046]

[0047] The carbonyl and dimertyrosine contents reflect the degree of protein oxidation. Table 1 shows that the carbonyl and dimertyrosine contents increase continuously with increasing plasma jet treatment time, indicating that plasma jet treatment accelerates protein oxidation. Compared to the control group, the total thiol content in CPI increases with treatment time during the first 30 seconds of plasma jet treatment. This may be because the active substances generated by plasma jet treatment alter the spatial structure of CPI, making the molecules more loose and exposing hidden thiol groups, thus increasing the thiol content. However, with a 50-second extension of treatment time, the total free -SH group content decreases. This indicates that with extended treatment time, more active substances are generated, and thiol groups are oxidized to disulfide bonds, leading to a decrease in their content.

[0048] The foaming properties of the modified chickpea protein isolate prepared in Example 1 were tested, and the results are as follows: Figure 1 As shown, by Figure 1 It was found that after 30 seconds of plasma jet treatment, the foaming properties and foam stability of chickpea protein isolate were significantly enhanced compared to the control group, but gradually deteriorated with increasing treatment time. The unfolding of protein chains in plasma-jet treated chickpea protein isolate resulted in a more flexible structure, making the chains more easily exposed to the water / air interface, thus generating more foam and improving its foaming properties. However, excessive unfolding of the protein side chains led to the formation of protein aggregates, reducing its foaming ability. This may be the reason for the decrease in foaming properties of modified chickpea protein isolate after 30 seconds of plasma jet treatment.

[0049] The emulsifying properties of the modified chickpea protein isolate prepared in Example 1 were tested, and the test results are as follows: Figure 2 As shown, by Figure 2 It was found that the emulsifying properties of chickpea protein isolate after plasma jet treatment also showed a change similar to foaming compared to the control group. Plasma treatment dissociates protein aggregates, exposing more active sites on the surface of protein micelles, enhancing the interaction with water molecules, and making smaller protein particles more easily adsorbed at the oil-water interface, thus improving emulsifying activity. Further extending the plasma jet treatment time caused insoluble chickpea protein particles to aggregate and gradually adsorb at the oil-water interface of the emulsion, thereby affecting the emulsifying properties of chickpea protein.

[0050] Therefore, plasma jet treatment can modify chickpea protein isolate through oxidation, and appropriate treatment conditions are crucial. Specifically, when the distance between the nozzle and the surface of the chickpea protein isolate is controlled at 40 mm, the gas flow rate is 30 L / min, and the treatment time is 30 s, the functional properties of chickpea protein isolate can be significantly improved, which has great application potential in the food industry.

[0051] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A method for preparing modified chickpea protein isolate, characterized in that, Includes the following steps: S1: Remove the chickpea skins, grind the chickpeas into chickpea flour, defatt the chickpea flour to obtain defatted chickpea flour. S2: Disperse defatted chickpea flour in deionized water to extract chickpea protein isolate; S31: Disperse chickpea protein isolate in a buffer solution with a pH of 6.5-7.5 to hydrate the chickpea protein isolate and form a hydrated chickpea protein isolate suspension with a protein concentration of 1%-3%. S32: At 0-8℃, the hydrated chickpea protein isolate suspension obtained in step S31 is subjected to plasma jet treatment. During plasma jet treatment, the distance between the plasma nozzle and the surface of the hydrated chickpea protein isolate suspension is 40mm, the jet outlet flow rate is 20-50 L / min, the plasma jet treatment time is 30s, and the suspension is allowed to stand at 4℃ for 12h to ensure sufficient reaction, thereby obtaining modified chickpea protein isolate.

2. The method for preparing the modified chickpea protein isolate as described in claim 1, characterized in that, Step S2 specifically includes: S21: Disperse defatted chickpea flour in deionized water, adjust pH to 8.5-9, stir for 30-240 min, centrifuge, take the supernatant, resuspend the precipitate and repeat the extraction 1-3 times, mix the supernatant to obtain the crude extract; S22: Adjust the pH of the crude extract obtained in step S21 to 4-5, centrifuge, and collect the precipitate; S23: Redissolve the precipitate collected in step S22 in water, adjust the pH to 7.0 to obtain chickpea protein isolate suspension, and freeze-dry to obtain chickpea protein isolate powder.

3. The method for preparing the modified chickpea protein isolate as described in claim 1, characterized in that, In step S1, chickpeas are ground into chickpea flour with a particle size of 1~15 μm.

4. The method for preparing the modified chickpea protein isolate as described in claim 1, characterized in that, In step S1, hexane is used to defatt the chickpea flour.

5. The method for preparing the modified chickpea protein isolate as described in claim 4, characterized in that, During the defatting process, the mass-to-volume ratio of chickpea flour to n-hexane is 1:(2~6).

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