阅读说明：本技术 一种月桂酰化水解小麦蛋白钾及其制备方法和应用 (Lauroyl hydrolyzed wheat protein potassium and preparation method and application thereof ) 是由 文茂 孟巨光 李建 于 2020-12-30 设计创作，主要内容包括：本发明属于护发、护肤技术领域,公开了一种月桂酰化水解小麦蛋白钾及其制备方法和应用。本发明月桂酰水解小麦蛋白钾是以绿色原料谷朊粉为基础,经多步酶水解得到低聚肽并进一步酰化后制备的新型肽表面活性剂,在中碱性条件下有一定泡沫性能的同时,克服了氨基酸表面活性剂的缺点,具有增稠特性,此外还可能具有肽的一些特殊功能,为化妆品行业提供了一个温和,有功效的表面活性剂选择。(The invention belongs to the technical field of hair care and skin care, and discloses lauroyl hydrolyzed wheat protein potassium and a preparation method and application thereof. The lauroyl hydrolysis wheat protein potassium is a novel peptide surfactant prepared by taking green raw material wheat gluten as a basis, obtaining oligopeptide through multi-step enzyme hydrolysis and further acylating, has certain foam performance under a medium-alkaline condition, overcomes the defects of an amino acid surfactant, has thickening property, possibly has certain special functions of peptide, and provides a mild and functional surfactant selection for the cosmetic industry.)

1. The lauroyl hydrolyzed wheat protein potassium is characterized in that: the lauroyl hydrolyzed wheat protein potassium has the following structure:

wherein n is the number of amino acid residues, mainly 1-5, distributed in 2-3 amino acids, and R₁、R₂Is a side chain of amino acid of wheat.

2. The potassium lauroylated hydrolyzed wheat protein of claim 1, wherein: the amino acid residue is more than one of glutamine, glutamic acid, proline and lysine.

3. The method for preparing potassium lauroylated hydrolyzed wheat protein according to claim 1, which comprises the following steps:

(1) hydrolyzing wheat gluten by adopting an enzymatic method, wherein the used enzymes are alkaline protease and trypsin, the preparation is carried out by adopting a mode of step-by-step enzyme supplementation, and insoluble substances are removed from the obtained hydrolysate through filtration separation or centrifugal separation to obtain transparent protein hydrolysate;

(2) heating the protein hydrolysate to 40-70 ℃, dropwise adding lauroyl chloride into the protein hydrolysate, controlling the reaction pH to be 8-12 by using potassium hydroxide, and reacting for 2-3h after the dropwise adding is finished to obtain a crude product of lauroyl hydrolyzed wheat protein potassium;

(3) adjusting the temperature of the crude product of lauroyl hydrolyzed wheat protein potassium to 50 ℃, adjusting the pH to 12, adding 27.5 mass percent of hydrogen peroxide for decoloring for 10min, and repeatedly adding 27.5 mass percent of hydrogen peroxide for decoloring until the color of the liquid becomes yellow;

(4) after the decolorization is finished, cooling the reaction liquid to room temperature, adjusting the pH value to 8-8.5, and carrying out suction filtration on the reaction liquid to obtain transparent yellow liquid, namely the lauroyl hydrolyzed wheat protein potassium; or adding hydrochloric acid into the reaction liquid to pH1-2, filtering, collecting solid, and dissolving the solid in deionized water to obtain transparent yellow liquid, i.e. potassium lauroyl hydrolyzed wheat protein.

4. The production method according to claim 3, characterized in that: the preparation in the step (1) is carried out by adopting a mode of step-by-step enzyme supplementation, and specifically comprises the following steps:

adding wheat gluten into deionized water to prepare a wheat gluten suspension with the mass fraction of 20%, adjusting the pH value to 9-11 by using potassium hydroxide, and uniformly stirring; heating to 50-60 deg.C, adding 0.05-0.2% alkaline protease, adjusting pH to 9-11 with potassium hydroxide, and reacting in water bath heater for 4 hr;

adding 0.05-0.1% of alkaline protease for reaction for 4 hours after the reaction is finished, and controlling the pH value to be 9-11 by using potassium hydroxide in the reaction process; repeating the process once;

thirdly, cooling to 40 ℃ and adding 1-2% trypsin for reaction for 4h, wherein the reaction pH is controlled to be 7-9 by potassium hydroxide in the reaction process; after the reaction is finished, adding hydrochloric acid to pH 3-4, and storing in a refrigerator.

5. The production method according to claim 3, characterized in that: the average number of amino acids of the oligopeptides in the protein hydrolysate in the step (1) is 2-3, and the degree of protein hydrolysis is 30% -50%.

6. The production method according to claim 3, characterized in that: and (2) in the step (1), the hydrolysate after hydrolysis is taken out, natural filtration or suction filtration is carried out by using medium-speed filter paper, the pH is adjusted to 6-8 after filtration is finished, natural filtration is carried out by using medium-speed filter paper, the pH is finally adjusted to 10-11, natural filtration is carried out by using medium-speed filter paper, the filtrate is collected to be protein hydrolysate, and the protein hydrolysate is stored in a refrigerator.

7. The production method according to claim 3, characterized in that: and (2) in the centrifugal separation in the step (1), taking out hydrolyzed hydrolysate, centrifuging at 6000rpm for 10min, adjusting the pH to 6-8 after the centrifugation is finished, centrifuging at 6000rpm for 10min, adjusting the pH to 10-11 after the centrifugation is finished, centrifuging at 6000rpm for 10min, collecting supernatant after the centrifugation is finished, removing the precipitate to obtain protein hydrolysate, and storing the protein hydrolysate in a refrigerator.

8. The production method according to claim 3, characterized in that: the dripping amount of the lauroyl chloride in the step (2) is calculated according to the following formula:wherein M is the addition amount of lauroyl chloride, V is the volume of protein hydrolysate, C is the concentration of wheat gluten suspension, and DH is the degree of protein hydrolysis.

9. The production method according to claim 3, characterized in that: the repeated adding times in the step (3) are 2 times, and the total volume of the added hydrogen peroxide is 3 percent of the crude product of the lauroyl hydrolysis wheat protein potassium.

10. Use of potassium lauroylated hydrolysed wheat protein according to claim 1 in cosmetics.

Technical Field

The invention belongs to the technical field of hair care and skin care, and particularly relates to lauroyl hydrolyzed wheat protein potassium and a preparation method and application thereof.

Background

Wheat protein (commonly called wheat gluten) is a byproduct in wheat starch production, has the protein content of 72-85 percent, complete amino acid composition, is a pure natural vegetable protein source with rich nutrition, high quality and low price, and can be classified into albumin, globulin, alcohol soluble protein and gluten according to different dissolution properties. In wheat protein, the mass fraction of albumin and globulin is about 10% of the total protein, and the two proteins are rich in lysine and are dissolved in dilute salt. The prolamin and glutelin are wheat storage proteins, the mass fraction of the prolamin and the glutelin is about 80% of that of wheat grain protein, the prolamin and the glutelin are rich in glutamine and proline, the prolamin is dissolved in 60-70% ethanol, and the glutelin is dissolved in dilute acid or dilute alkali.

In recent years, proteins have been increasingly used as conceptual components in cosmetics, and proteins used in cosmetics are mainly derived from animal and plant extracts, and further, there has been a concern that protein hydrolysates, which are adsorbed on the surface of keratin structures by weak force to protect hair and skin, are used as active ingredients in hair care and high quality cosmetics, and skin and surface layers of hair are mainly composed of keratin structures, and furthermore, peptides having a molecular weight of less than 3000da are permeated into the dermis and cortex of skin, which can promote cell growth. The wheat oligopeptide is a small molecular peptide with the length of about 2-6 amino acids, which is obtained by decomposing and separating wheat gluten through specific enzyme, and the wheat oligopeptide is easier to absorb and better to dissolve in water than protein, and simultaneously keeps some special biological activity. In recent years, more and more cosmetics are prepared by amino acid derivatization, and the surfactant is mild but has obvious defects, and the amino acid surfactant is difficult to thicken. Therefore, on the basis of preparing oligopeptide by hydrolyzing protein, the peptide surfactant is prepared by one-step derivatization, so that a novel product with conditioning property and thickening property is developed, and more choices are provided for the cosmetic industry.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention mainly aims to provide the potassium lauroyl hydrolyzed wheat protein.

The invention also aims to provide a preparation method of the potassium lauroyl hydrolyzed wheat protein.

The invention further aims to provide application of the potassium lauroyl hydrolyzed wheat protein.

The purpose of the invention is realized by the following technical scheme:

a potassium lauroylated hydrolyzed wheat protein having the following structure:

wherein n is the number of amino acid residues, mainly 1-5, distributed in 2-3 amino acids, and R₁、R₂Is a side chain of amino acid of wheat.

The amino acid residue is more than one of glutamine, glutamic acid, proline and lysine.

The preparation method of the lauroyl hydrolyzed wheat protein potassium comprises the following operation steps:

(1) hydrolyzing wheat gluten by adopting an enzymatic method, wherein the used enzymes are alkaline protease and trypsin, the preparation is carried out by adopting a mode of step-by-step enzyme supplementation, and insoluble substances are removed from the obtained hydrolysate through filtration separation or centrifugal separation to obtain transparent protein hydrolysate;

(2) heating the protein hydrolysate to 40-70 ℃, dropwise adding lauroyl chloride into the protein hydrolysate, controlling the reaction pH to be 8-12 by using potassium hydroxide, and reacting for 2-3h after the dropwise adding is finished to obtain a crude product of lauroyl hydrolyzed wheat protein potassium;

(3) adjusting the temperature of the crude product of lauroyl hydrolyzed wheat protein potassium to 50 ℃, adjusting the pH to 12, adding 27.5 mass percent of hydrogen peroxide for decoloring for 10min, and repeatedly adding 27.5 mass percent of hydrogen peroxide for decoloring until the color of the liquid becomes yellow;

(4) after the decolorization is finished, cooling the reaction liquid to room temperature, adjusting the pH value to 8-8.5, and carrying out suction filtration on the reaction liquid to obtain transparent yellow liquid, namely the lauroyl hydrolyzed wheat protein potassium; or adding hydrochloric acid into the reaction liquid to pH1-2, filtering, collecting solid, and dissolving the solid in deionized water to obtain transparent yellow liquid, i.e. potassium lauroyl hydrolyzed wheat protein.

The preparation in the step (1) is carried out by adopting a mode of step-by-step enzyme supplementation, and specifically comprises the following steps:

adding wheat gluten into deionized water to prepare a wheat gluten suspension with the mass fraction of 20%, adjusting the pH value to 9-11 by using potassium hydroxide, and uniformly stirring; heating to 50-60 deg.C, adding 0.05-0.2% alkaline protease, adjusting pH to 9-11 with potassium hydroxide, and reacting in water bath heater for 4 hr;

adding 0.05-0.1% of alkaline protease for reaction for 4 hours after the reaction is finished, and controlling the pH value to be 9-11 by using potassium hydroxide in the reaction process; repeating the process once;

thirdly, cooling to 40 ℃ and adding 1-2% trypsin for reaction for 4h, wherein the reaction pH is controlled to be 7-9 by potassium hydroxide in the reaction process; after the reaction is finished, adding hydrochloric acid to pH 3-4, and storing in a refrigerator.

The average number of amino acids of the oligopeptides in the protein hydrolysate in the step (1) is 2-3, and the degree of protein hydrolysis is 30% -50%.

And (2) in the step (1), the hydrolysate after hydrolysis is taken out, natural filtration or suction filtration is carried out by using medium-speed filter paper, the pH is adjusted to 6-8 after filtration is finished, natural filtration is carried out by using medium-speed filter paper, the pH is finally adjusted to 10-11, natural filtration is carried out by using medium-speed filter paper, the filtrate is collected to be protein hydrolysate, and the protein hydrolysate is stored in a refrigerator.

And (2) in the centrifugal separation in the step (1), taking out hydrolyzed hydrolysate, centrifuging at 6000rpm for 10min, adjusting the pH to 6-8 after the centrifugation is finished, centrifuging at 6000rpm for 10min, adjusting the pH to 10-11 after the centrifugation is finished, centrifuging at 6000rpm for 10min, collecting supernatant after the centrifugation is finished, removing the precipitate to obtain protein hydrolysate, and storing the protein hydrolysate in a refrigerator.

The dripping amount of the lauroyl chloride in the step (2) is calculated according to the following formula:wherein M is lauroyl chloride addition amount, V is protein hydrolysate volume, and C is wheat gluten suspensionConcentration, DH is the degree of proteolysis.

The repeated adding times in the step (3) are 2 times, and the total volume of the added hydrogen peroxide is 3 percent of the crude product of the lauroyl hydrolysis wheat protein potassium.

The lauroyl hydrolyzed wheat protein potassium is applied to cosmetics.

The pH value of the hydrolysate is controlled to adjust the dissolution characteristics of each peptide component, and insoluble substances are removed by filtration separation or centrifugal separation to improve the stability and transparency of the hydrolysate.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the novel surfactant is prepared by hydrolyzing wheat protein with enzyme and acylating the hydrolyzed wheat protein, has the surface activity foaming performance close to that of amino acid, can play a thickening role in a formula system, is a novel product capable of thickening, and provides more choices for the cosmetic industry.

(2) The lauroyl hydrolyzed wheat protein is prepared by a green method, the surfactant has high safety and low irritation, also has a peptide side chain, can be adsorbed to the head surface to form a protective layer, can promote the growth of epidermal cells, and has a conditioning characteristic.

Drawings

FIG. 1 is a graph showing the degree of hydrolysis and yield of wheat gluten in various processes.

FIG. 2 is a graph of the active and salt content for different acylation processes.

Figure 3 is the foam performance of the surfactant at different pH's, with potassium lauroyl hydrolyzed wheat protein on the left and sodium cocoyl alaninate on the right.

FIG. 4 is a flow chart of the preparation process of potassium lauroyl hydrolyzed wheat protein of the present invention.

FIG. 5 is a flow chart of the preparation process of potassium lauroyl hydrolyzed wheat protein of the present invention.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto. The flow chart of the preparation process of the potassium lauroyl hydrolyzed wheat protein is shown in figure 4, and the reaction equation of the preparation process is shown in figure 5.

The degree of proteolysis and the protein yield in example 1, comparative example 1.1, comparative example 1.2 and comparative example 1.3 are calculated as follows:

(1) settlement of degree of proteolysis:

degree of hydrolysis of wheat protein: the method is only applicable to reactions with pH greater than 6, as determined by the pH-stat method. Recording initial pH, gradually reducing the pH in the reaction process, dropwise adding 1M sodium hydroxide to control the pH of the reaction to be about the initial value, recording the volume of the consumed sodium hydroxide, wherein the amount of the consumed sodium hydroxide corresponds to the released peptide bonds one by one, and calculating the hydrolysis degree according to a formula F1, wherein B is the consumption amount of the sodium hydroxide, N is the concentration of the sodium hydroxide, M is the mass of protein, and the content of wheat protein in the wheat gluten is 80% by determination. In addition, alpha and h_totValues are shown in Table 1, h_totThe millimole number of peptide bonds per gram of raw protein is 8.38 for wheat protein;the pH is the initial pH of the reaction, and the pka is the pka value of the amino group at the corresponding temperature:

F1：

TABLE 1 alpha and h_totValue of

(2) Calculation of protein yield

Drying the solid obtained by centrifuging or filtering the hydrolysate, wherein the protein is dissolved under enzymolysis, and other components such as polysaccharide and fat are not dissolved, so as to calculate the mass of the dissolved protein by subtracting the weight of the removed precipitate from the weight of the added solid, thereby obtaining the protein yield, and calculatingFormula F2, wherein M₁In terms of the mass of gluten added, M₂The solid mass obtained by centrifugation or filtration.

F2：

Example 1

Hydrolyzing vital gluten by adopting an enzymatic method to obtain hydrolysate, which specifically comprises the following steps:

(1) adding wheat gluten into deionized water to prepare a wheat gluten suspension with the mass fraction of 20%, adjusting the pH value to 10.5 by using a 10M potassium hydroxide solution, and uniformly stirring; heating to 60 ℃, adding 0.05% of alkaline protease, adjusting the pH to 10.5 by using 10M potassium hydroxide solution, and placing the mixture into a water bath heater for reaction for 4 hours;

(2) after the reaction is finished, adding 0.05 percent of alkaline protease for reaction for 4 hours, and controlling the pH value to be 10.5 by using 10M potassium hydroxide solution in the reaction process; repeating the process once;

(3) finally, cooling to 40 ℃, adding 1% trypsin for reaction for 4 hours, and controlling the reaction pH to 7.5 by using 10M potassium hydroxide solution in the reaction process; after the reaction is finished, adding hydrochloric acid to pH 3-4, and storing in a refrigerator.

Comparative example 1.1

Hydrolyzing vital gluten by adopting an enzymatic method to obtain hydrolysate, which specifically comprises the following steps:

(1) adding wheat gluten into deionized water to prepare a wheat gluten suspension with the mass fraction of 20%, adjusting the pH value to 10.5 by using a 10M potassium hydroxide solution, and uniformly stirring; heating to 60 ℃, adding 0.1% of alkaline protease, adjusting the pH to 10.5 by using 10M potassium hydroxide solution, and placing the mixture into a water bath heater for reaction for 4 hours;

(2) after the reaction is finished, adding 0.05 percent of alkaline protease for reaction for 4 hours, and controlling the pH value to be 10.5 by using 10M potassium hydroxide solution in the reaction process; repeating the process once;

(3) finally, cooling to 40 ℃, adding 1% trypsin for reaction for 4 hours, and controlling the reaction pH to 7.5 by using 10M potassium hydroxide solution in the reaction process; after the reaction is finished, adding hydrochloric acid to pH 3-4, and storing in a refrigerator.

Comparative example 1.2

Hydrolyzing vital gluten by adopting an enzymatic method to obtain hydrolysate, which specifically comprises the following steps:

(1) adding wheat gluten into deionized water to prepare a wheat gluten suspension with the mass fraction of 20%, adjusting the pH value to 10.5 by using a 10M potassium hydroxide solution, and uniformly stirring; heating to 60 ℃, adding 0.2% of alkaline protease, adjusting the pH to 10.5 by using 10M potassium hydroxide solution, and placing the mixture into a water bath heater for reaction for 4 hours;

(2) after the reaction is finished, adding 0.05 percent of alkaline protease for reaction for 4 hours, and controlling the pH value to be 10.5 by using 10M potassium hydroxide solution in the reaction process; repeating the process once;

(3) finally, cooling to 40 ℃, adding 1% trypsin for reaction for 4 hours, and controlling the reaction pH to 7.5 by using 10M potassium hydroxide solution in the reaction process; after the reaction is finished, adding hydrochloric acid to pH 3-4, and storing in a refrigerator.

Comparative example 1.3

Hydrolyzing vital gluten by adopting an enzymatic method to obtain hydrolysate, which specifically comprises the following steps:

(1) adding wheat gluten into deionized water to prepare a wheat gluten suspension with the mass fraction of 20%, adjusting the pH value to 10.5 by using a 10M potassium hydroxide solution, and uniformly stirring; heating to 60 ℃, adding 0.05% of alkaline protease, adjusting the pH to 10.5 by using 10M potassium hydroxide solution, and placing the mixture into a water bath heater for reaction for 4 hours;

(2) after 4h of reaction, 0.05% alkaline protease was added into the reactor, and the reaction was repeated once with the pH being controlled at 10.5 with 10M potassium hydroxide solution.

(3) After the second step, the temperature is reduced to 40 ℃, 2% trypsin is added, the pH is adjusted to 7.5, the pH is controlled by 10M potassium hydroxide solution in the reaction process, and the reaction is carried out for 4 hours.

The color and odor of the hydrolysate obtained by hydrolyzing wheat gluten according to the methods described in example 1, comparative example 1.1, comparative example 1.2 and comparative example 1.3 were substantially uniform, and the results of comparison of the degree of protein hydrolysis and the protein yield, which are characteristic odors of amber liquid and wheat protein, are shown in fig. 1.

The results show that the hydrolysis degrees of the wheat protein obtained by adopting the hydrolysis of the methods are not very different, the hydrolysis degrees are all about 50 percent, the peptide length obtained by conversion according to the hydrolysis degrees is about two amino acids, the alkaline protease amount is increased to 0.2 percent, the hydrolysis degree is not increased to 5 percent, and the yield is not increased basically. Furthermore, increasing trypsin did not increase the degree of hydrolysis and yield.

Example 2

Separating the hydrolysate to obtain transparent protein hydrolysate, which specifically comprises the following steps:

(1) adjusting the pH value of the hydrolysate obtained in the example 1 to 3.0 by using potassium hydroxide, uniformly stirring, centrifuging at 6000rpm for 10min, discarding the precipitate, and collecting the supernatant;

(2) adjusting pH to 7.0 with potassium hydroxide, centrifuging at 6000rpm for 10min, discarding precipitate, and collecting supernatant;

(3) adjusting pH to 10.0 with potassium hydroxide, centrifuging at 6000rpm for 10min, discarding precipitate, and collecting supernatant to obtain transparent protein hydrolysate.

Comparative example 2.1

Separating the hydrolysate to obtain transparent protein hydrolysate, which specifically comprises the following steps:

(1) adjusting the pH value of the hydrolysate obtained in the example 1 to 3.0 by using potassium hydroxide, stirring and mixing uniformly, naturally filtering, discarding the precipitate, and collecting the filtrate.

(2) Adjusting pH to 7.0 with potassium hydroxide, and naturally filtering; adjusting pH to 10.0 with potassium hydroxide, filtering naturally, discarding precipitate, and collecting filtrate to obtain transparent protein hydrolysate.

Comparative example 2.2

Separating the hydrolysate to obtain transparent protein hydrolysate, which specifically comprises the following steps:

(1) adjusting the pH value of the hydrolysate obtained in the example 1 to 3.0 by using potassium hydroxide, stirring and mixing uniformly, carrying out vacuum filtration, discarding the precipitate, and collecting filtrate.

(2) Adjusting pH to 7.0 with potassium hydroxide, and naturally filtering; adjusting pH to 10.0 with potassium hydroxide, filtering naturally, discarding precipitate, and collecting filtrate to obtain transparent protein hydrolysate.

The amount of lauroyl chloride added dropwise as described in example 3, comparative example 3.1, comparative example 3.2 and comparative example 3.3 belowCalculated according to the following formula F3, F3:wherein M is the addition amount of lauroyl chloride, V is the volume of protein hydrolysate, C is the concentration of wheat gluten suspension, and DH is the degree of protein hydrolysis.

Example 3

A method for preparing lauroyl hydrolyzed wheat protein potassium comprises the following steps:

(1) and (3) putting the protein hydrolysate obtained in the example 2 into a reactor, heating to 60 ℃, slowly stirring, dropwise adding lauroyl chloride, dropwise adding a 10M potassium hydroxide solution to control the reaction pH to be 11, and reacting for 3 hours after the dropwise adding is finished to obtain the lauroyl hydrolyzed wheat protein potassium.

(2) Cooling to 50 deg.C, adjusting pH to 12 with 10M potassium hydroxide solution, adding 27.5% H in three batches₂O₂(addition of H in each batch)₂O₂The volume of the sodium lauroyl hydrolysis wheat protein potassium is 1 percent of the volume of a crude product of lauroyl hydrolysis wheat protein potassium), each batch is decolorized for 10min, the temperature is reduced to normal temperature after the decolorization is finished, the pH value is adjusted to 8.5 by using 10M potassium hydroxide solution, and a transparent orange-yellow liquid, namely the lauroyl hydrolysis wheat protein potassium, is obtained by suction filtration.

Comparative example 3.1

A method for preparing lauroyl hydrolyzed wheat protein potassium comprises the following steps:

(1) and (3) putting the protein hydrolysate obtained in the example 2 into a reactor, heating to 70 ℃, slowly stirring, dropwise adding lauroyl chloride, dropwise adding a 10M potassium hydroxide solution to control the reaction pH to be 11, and reacting for 3 hours after the dropwise adding is finished to obtain the lauroyl hydrolyzed wheat protein potassium.

(2) Cooling to 50 deg.C, adjusting pH to 12 with 10M potassium hydroxide solution, adding 27.5% H in three batches₂O₂(addition of H in each batch)₂O₂The volume of the sodium lauroyl hydrolysis wheat protein potassium is 1 percent of the volume of a crude product of lauroyl hydrolysis wheat protein potassium), each batch is decolorized for 10min, the temperature is reduced to normal temperature after the decolorization is finished, the pH value is adjusted to 8.5 by using 10M potassium hydroxide solution, and a transparent orange-yellow liquid, namely the lauroyl hydrolysis wheat protein potassium, is obtained by suction filtration.

Comparative example 3.2

A method for preparing lauroyl hydrolyzed wheat protein potassium comprises the following steps:

(1) and (3) putting the protein hydrolysate obtained in the example 2 into a reactor, heating to 50 ℃, slowly stirring, dropwise adding lauroyl chloride, dropwise adding a 10M potassium hydroxide solution to control the reaction pH to be 11, and reacting for 3 hours after the dropwise adding is finished to obtain the lauroyl hydrolyzed wheat protein potassium.

(2) Controlling the temperature at 50 ℃, adjusting the pH to 12 by using 10M potassium hydroxide solution, and adding H with the mass fraction of 27.5 percent in three batches₂O₂(addition of H in each batch)₂O₂The volume of the sodium lauroyl hydrolysis wheat protein potassium salt is 1 percent of the volume of a crude product of lauroyl hydrolysis wheat protein potassium), each batch is decolorized for 10min, the temperature is reduced to normal temperature after the decolorization is finished, the pH value is adjusted to 8.5 by using 10M potassium hydroxide solution, hydrochloric acid is added to the pH value of 1.0, the mixture is filtered and collected, the precipitate is dissolved in deionized water again, the pH value is adjusted to 8.5 by using 10M potassium hydroxide solution, and transparent orange yellow liquid is obtained, namely the potassium lauroyl hydrolysis wheat protein.

Comparative example 3.3

A method for preparing lauroyl hydrolyzed wheat protein potassium comprises the following steps:

(1) and (3) putting the protein hydrolysate obtained in the example 2 into a reactor, reacting at the normal temperature of about 30 ℃, slowly stirring, dropwise adding lauroyl chloride, dropwise adding a 10M potassium hydroxide solution to control the reaction pH to be 11, and reacting for 3 hours after the dropwise adding is finished to obtain the lauroyl hydrolyzed wheat protein potassium.

(2) Heating to 50 deg.C, adjusting pH to 12 with 10M potassium hydroxide solution, adding 27.5% H in three batches₂O₂(addition of H in each batch)₂O₂The volume of the sodium lauroyl hydrolysis wheat protein potassium salt is 1 percent of the volume of a crude product of the sodium lauroyl hydrolysis wheat protein potassium, each batch of the sodium lauroyl hydrolysis wheat protein potassium salt is decolorized for 10min, the temperature is reduced to normal temperature after the decolorization is finished, the pH is adjusted to 8.5 by using 10M potassium hydroxide solution, hydrochloric acid is added to the pH value of 1.0, the sodium lauroyl hydrolysis wheat protein potassium salt is subjected to suction filtration, the precipitate is collected, the precipitate is dissolved in deionized water again, and the pH is adjusted to 8.5.

The lauroyl-hydrolyzed wheat protein potassium prepared by the above methods has the active substance, sodium chloride and lauric acid contents shown in figure 2, when the temperature is lower than 50 ℃, the lauric acid content is increased, the active substance content is reduced, the active substance content can reach about 24% at the temperature of above 60 ℃, and the lauric acid content is less than 2%. Amino acid surfactants can be prepared at normal temperature to obtain products with low lauric acid content, while peptide surfactants have poor effect at low temperature, which indicates that lauroyl is difficult to be connected to peptide molecules, so that the reaction activity needs to be improved by heating.

Example 4

Storage and stability of potassium lauroyl hydrolyzed wheat protein:

in order to prevent microbial spoilage, 1% (W/W) of sodium benzoate is added into the lauroyl-hydrolyzed wheat protein potassium obtained in example 3 to serve as a preservative, and in addition, the stability is observed in A, B, C, D groups according to different separation processes and different treatment modes after the lauroyl-hydrolyzed wheat protein potassium is decolorized, wherein the storage temperature is 30 ℃, the separation process A is centrifugation, and the treatment process is filtration; the separation process is centrifugation, and the treatment process is acid precipitation and redissolution; c, the separation process is filtration, and the treatment process is filtration; the separation process is filtration, and the treatment process is acid precipitation and redissolution.

TABLE 2 Potassium lauroyl hydrolysed wheat protein stability

The stability of the potassium lauroyl-hydrolyzed wheat protein is shown in Table 2, 1% (W/W) of sodium benzoate can play an effective preservative effect, and the sample is not rotten after being placed for one month. The centrifugal separation effect is better than the filtration separation effect, and substances with larger molecular weight or poorer solubility in the peptide liquid are also separated, so that the prepared surfactant has better stability; on the other hand, although the acid precipitation and re-filtration method improves the processing speed, the stability of the product is slightly poor, the transparency of the surfactant is reduced after the product is stored for 30 days, and the stability of the product adopting the filtration method is better.

Application Performance test examples

(1) Referring to the GBT 29679-2013 method, the foam performance of surfactants with different pH values is tested according to the same active matter concentration, the specific experiment result is shown in figure 3, and the left side of the figure is the lauroyl hydrolysis wheat protein potassium obtained in example 3; the right of the figure is sodium cocoyl alanine.

As can be seen from FIG. 3, under neutral to alkaline conditions, the foam performances of potassium lauroyl-hydrolyzed wheat protein and sodium cocoyl alanine are similar, and the foam heights are both about 200; under the weak acid condition, the foam performance of potassium lauroyl-hydrolyzed wheat protein is poor and is only about 50, but the foam capability of sodium cocoyl alanine is not affected. The lauroyl hydrolyzed wheat protein potassium can be applied to cosmetics under medium-alkaline conditions.

(2) The potassium lauroyl-hydrolyzed wheat protein obtained in example 3 was measured for thickening properties:

table 3 test formulations

TABLE 4 thickening Properties of surfactants

With the test formulations in Table 3, the viscosity and pH of each sample are shown in Table 4 without adjusting the pH of the formulation, and it can be seen that potassium lauroyl-hydrolyzed wheat protein has a distinct easy thickening property. When the pH value is gradually increased, the consistency of the lauroyl hydrolyzed wheat protein potassium is obviously increased, and the consistency of the sodium cocoyl alaninate is obviously reduced; when the pH becomes gradually smaller, the change in consistency is reversed. Therefore, the potassium lauroyl-hydrolyzed wheat protein can play a thickening role in a formula system, but an amino acid surfactant does not have the thickening role, and in addition, the potassium lauroyl-hydrolyzed wheat protein has a peptide side chain and possibly also has a physiological function.

(3) EXAMPLE 3 irritation test of Potassium lauroyl-hydrolyzed wheat protein

Here, theThe irritation of potassium lauroyl-hydrolyzed wheat protein as a surfactant is measured by using zein, and the amino acid amount hydrolyzed by the zein is different due to different irritation of the surfactants. The zein test method is carried out by measuring the zein value, i.e. the nitrogen content (N) measured in the presence of prolamin in a surfactant solution₁) And nitrogen content (N) measured in the absence of alcohol soluble protein₂) The difference, i.e. Zein ═ N₁-N₂The unit is mg or g/L, and the stimulation intensity of the surfactant is judged. When Zein>4g/L, the surfactant is strong in irritation; when the concentration is 2g/L<Zein<4g/L, the surfactant has low irritation; when Zein<2g/L, it is shown that the surfactant is non-irritating.

TABLE 5 comparison of irritancy of various surfactants

The results of the irritation test of each surfactant are shown in table 5, the Zein value of potassium lauroyl-hydrolyzed wheat protein is less than 2, the potassium lauroyl-hydrolyzed wheat protein is judged to be non-irritating, sodium lauryl sulfate has strong irritation, and the other three surfactants have low irritation, namely the potassium lauroyl-hydrolyzed wheat protein is based on green raw material wheat gluten and is hydrolyzed under the action of enzyme, wherein the chemical components are less in content, so the surfactant is very mild.

In conclusion, the lauroyl-hydrolyzed wheat protein potassium is a peptide surfactant prepared by taking green raw material wheat gluten as a basis and carrying out multi-step enzymatic hydrolysis and acylation, has equivalent foam performance under the medium-alkaline condition, overcomes the defects of an amino acid surfactant in a formula, has thickening property, possibly has some special functions of peptide, and provides a mild and functional surfactant selection for the cosmetic industry.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.