Citrus-flavored detoxified cottonseed protein peptide facial cleanser and preparation method thereof

Abstract

The application discloses a citrus-scented detoxified cottonseed protein peptide facial cleanser and a preparation method thereof, and belongs to the technical field of daily chemical products and bioactive peptides. In the application, gossypol is removed from cottonseed meal through solid-state fermentation of plant lactobacillus, and cottonseed protein peptides are obtained after water washing and neutral protease hydrolysis. Then, the detoxified cottonseed protein peptides are used as core active ingredients, and are compounded with amino acid surfactants, polyhydric alcohols, thickening systems and citrus essential oils extracted from citrus peels through a cleaning method to prepare the citrus-scented detoxified cottonseed protein peptide facial cleanser. In the application, cottonseed protein peptides are used in the facial cleanser, the product is safe and stable, natural citrus essential oils are used to replace traditional chemical synthetic fragrances, the product has a citrus fragrance which is pleasing and easy to be accepted by consumers, meets the daily chemical product specifications, is suitable for industrial scale production, realizes high-value utilization of cottonseed meal and preparation of a commercialized citrus-scented facial cleanser.

Description

Technical Field

[0001] This invention belongs to the field of daily chemical products and bioactive peptide technology, specifically relating to a citrus-scented detoxified cottonseed protein peptide facial cleanser and its preparation method. Background Technology

[0002] Traditional soap-based cleansers are powerful but irritating, easily damaging the skin's slightly acidic barrier. While mainstream amino acid cleansers offer improved gentleness, they generally suffer from a difficulty in balancing cleansing power and gentleness, and their performance is often limited. Traditional synthetic fragrances, though cost-effective, lack the biocompatibility and dynamic aroma profile of natural fragrances, and may even pose certain health risks, making them difficult for consumers to accept. With the rise of the pure beauty concept, consumer demand for cleansers has shifted from basic cleansing to a combination of gentle cleansing, effective skincare, and natural safety. Plant-based cleansers with high biocompatibility and clearly defined efficacy are becoming a new development direction. Cottonseed protein peptides are small-molecule active peptides prepared by enzymatic hydrolysis of cottonseed protein. Existing research has confirmed their excellent antioxidant, immunomodulatory, and non-cytotoxic properties, and they have already seen initial applications in the food and animal feed industries.

[0003] Cottonseed meal is a low-cost, renewable raw material for preparing cottonseed protein peptides; however, its content of gossypol is toxic, posing a major safety barrier to the application of cottonseed protein peptides in the daily chemical industry. Cottonseed protein peptides prepared from detoxified cottonseed meal using a one-step enzymatic hydrolysis process exhibit excellent foaming properties, emulsifying properties, in vitro antioxidant activity, and digestible stability, laying a solid raw material and theoretical foundation for their application in daily chemical products. Citrus essential oil, rich in monoterpenes, can be directly and cleanly extracted from the abundant orange peel. Citrus essential oil possesses good lipophilicity, anti-inflammatory activity, antioxidant activity, and antibacterial activity. Simultaneously, its refreshing citrus aroma can relieve stress and regulate mood, adding a pleasant sensory experience to the facial cleansing process and improving user satisfaction. Therefore, citrus-scented facial cleansers prepared by adding natural citrus essential oil to cleansing products have enormous market potential.

[0004] Despite the multiple potential applications of cottonseed protein peptides in facial cleansing products, significant gaps remain in current research both domestically and internationally. Existing studies almost entirely focus on their applications in the food and animal feed sectors. Systematic research on their compatibility, dose-response relationships, and efficacy verification in wash-off cosmetics is lacking. The limited number of studies related to cosmetics also only provide in vitro validation of their antioxidant activity, failing to explore their impact on the overall performance of facial cleansing products, and neglecting human trials to assess their effectiveness. This severely restricts the industrial application of cottonseed protein peptides in the cosmetics sector.

[0005] Chinese patent application CN202510154417.1, published on June 24, 2025, discloses an enzymatic extraction method for cottonseed protein peptides optimized based on machine learning. This patent only relates to the optimization of enzymatic hydrolysis conditions for cottonseed protein peptides and does not address the application of the obtained cottonseed protein peptides in the field of facial cleansing products. Chinese patent application CN201810653284.2, published on November 9, 2018, discloses a method for producing fermented cottonseed protein peptides. This patent employs a two-stage solid-state fermentation method. First, *Pichia pastoris* and *Bacillus natto* are used for solid-state fermentation to remove phenolic cottonseed protein. Then, *Bacillus subtilis*, *Bacillus coagulans*, and mannanase are inoculated for a secondary fermentation, finally yielding fermented cottonseed protein peptides. The obtained cottonseed protein peptides are mainly used in the high-end animal feed field and not in the facial cleansing product field. Chinese patent application number CN201410528451.2, published on February 11, 2015, discloses a method for preparing dephenolized cottonseed protein peptides. This patent uses Bacillus subtilis as a fermentation strain to ferment liquid-fermented cottonseed meal to remove gossypol from the cottonseed meal.

[0006] In summary, existing technologies lack facial cleansing products that combine targeted modification of cottonseed protein peptides with a synergistic efficacy system, failing to simultaneously meet the needs for safety and compliance, anti-oxidation, cell repair, and gentle cleansing, thus presenting significant technological gaps and application limitations. Summary of the Invention

[0007] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a citrus-scented detoxified cottonseed protein peptide facial cleanser and its preparation method.

[0008] To address the aforementioned issues, this invention features a novel formulation: a synergistic effect of cottonseed peptides and citrus essential oils, enhancing cleansing, foaming, antioxidant properties, irritation reduction, biocompatibility, and consumer acceptance.

[0009] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a method for preparing detoxified cottonseed protein peptides, comprising the following steps: S1. Using cottonseed meal as raw material, inoculate with Lactobacillus plantarum for solid-state fermentation to remove gossypol and obtain detoxified cottonseed meal raw material; S2. The detoxified cottonseed meal raw material is enzymatically hydrolyzed with neutral protease to obtain cottonseed protein peptides; Preferably, in S1, the protein content of the cottonseed meal is 60% (abbreviated as 60 cottonseed meal), the inoculation amount of *Lactobacillus plantarum* is 8-12%, the ratio of cottonseed meal to water is 10 g: 4-6 mL, and the fermentation conditions include: fermentation temperature of 28-39℃ and fermentation time of 50-70 h.

[0010] Preferably, in S2, the ratio of detoxified cottonseed meal to neutral protease aqueous solution is 1 g: 15~25 mL, the amount of neutral protease added based on the weight of cottonseed meal is 6~8 wt%, and the enzymatic hydrolysis conditions include: enzymatic hydrolysis temperature of 40~60℃ and enzymatic hydrolysis time of 5~12 h.

[0011] Secondly, the present invention provides the application of the aforementioned detoxified cottonseed protein peptides in the preparation of non-irritating, fragrance-free topical cleaning daily chemical products.

[0012] Preferably, the external cleaning daily chemical product is a facial cleanser.

[0013] The facial cleanser prepared by this invention has a pH of 6.04-6.73, which matches the slightly acidic environment of the skin. It has a low Zein value, low irritation, fine and stable foam, good cleansing power, and also exhibits DPPH and ABTS. + Free radical scavenging ability.

[0014] Thirdly, the present invention provides a facial cleanser containing cottonseed protein peptides, wherein, by weight percentage (100%), other components include: Detoxified cottonseed protein peptides: 1.0wt%–5.0wt%; Fragrance-enhancing essential oils: 0.2wt%–1.0wt%; Surfactant system 10wt%~40wt%; Moisturizer 10wt%~40wt%; Thickener 0.1wt%~5.0wt%; Preservatives: 0.1 wt%–1.1 wt%; Deionized water balance.

[0015] Preferably, the flavoring essential oil is citrus peel essential oil, which is extracted from citrus peel by steam distillation. The surfactant system is a compound of amino acid-based surfactants, amphoteric surfactants, and nonionic surfactants, specifically consisting of 25.0 wt% potassium cocoyl glycinate, 5.0 wt% cocamidopropyl betaine, and 5.0 wt% decyl glucoside. The moisturizers are glycerin 30.0 wt% and dipropylene glycol 5.0 wt%. The thickeners are 3.0 wt% carbomer SF-1 and 0.4 wt% xanthan gum. The preservatives are 0.9 wt% phenoxyethanol and 0.1 wt% ethylhexylglycerin.

[0016] Preferably, the method for extracting the citrus essential oil includes: Freshly crushed citrus peels are placed in a reaction vessel with two feeding ports, distilled water is added, and the vessel is heated in an oil bath at 150-170°C. Simultaneously, steam is continuously introduced into the bottom of the flask through one feeding port. The steam containing essential oil that evaporates from the other feeding port is collected by a condenser and allowed to stand and separate into layers. Distillation is stopped when the distillate changes from turbid to clear. The clear yellow oily liquid collected on the upper layer is citrus essential oil. The ratio of citrus peel to distilled water is 30g: 15~25mL.

[0017] Fourthly, the present invention provides a method for preparing a facial cleanser containing cottonseed protein peptides, comprising the following steps: (1) Under the conditions of 85~95℃ water bath, the surfactant system, humectant and deionized water are mixed and stirred for 40~50min to form a homogeneous system; (2) Add thickener and disperse and swell at high speed of 300~500 r / min for 5~15 min; (3) Cool down to 40~50℃, add the detoxified cottonseed protein peptide, and ultrasonically disperse at 250~350 W for 3~7 min until uniform; (4) Cool the mixture to 20-30°C, add flavoring citrus essential oil and preservative, stir well and let it stand for 15-20 minutes to remove bubbles, and obtain the facial cleanser containing cottonseed protein peptide.

[0018] This invention has at least one of the following beneficial effects: 1. This invention improves the safety and stability of cottonseed protein peptides through fermentation detoxification and enzymatic hydrolysis, and also improves the hydrophilicity of the protein peptides. By using cottonseed protein peptides in facial cleansing products, the mildness and antioxidant properties of the cleansing products can be improved. The product has good stability and is suitable for industrial production.

[0019] 2. This invention incorporates citrus essential oil, rich in monoterpenes, which can be directly extracted from the abundant orange peel. This gives the product excellent lipophilicity, anti-inflammatory activity, antioxidant activity, and antibacterial activity, while also providing a pleasant citrus aroma. The refreshing citrus scent can relieve stress and regulate mood, adding a pleasant sensory experience to the face-washing process and enhancing user satisfaction. Therefore, this citrus-scented facial cleanser has significant market potential. Attached Figure Description

[0020] Figure 1 A comparison of the foaming properties of facial cleansers in different embodiments and comparative examples.

[0021] Figure 2 This is the standard curve for bovine serum albumin.

[0022] Figure 3Comparison of in vitro antioxidant activity of facial cleansers with different amounts of detoxified cottonseed protein peptides (essential oil addition 0.4wt%).

[0023] Figure 4 Comparison of in vitro antioxidant activity of facial cleansers with different amounts of added citrus essential oil (2wt% detoxified cottonseed protein peptide). Detailed Implementation

[0024] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0025] Terminology Explanation: Unless otherwise defined, all technical terms used in this document are consistent with the common understanding of those skilled in the art; all references cited herein are incorporated herein in their entirety.

[0026] Cottonseed protein peptides: Small molecule plant-derived bioactive peptides prepared from cottonseed meal with a protein content of 60% (abbreviated as 60 cottonseed meal) through solid-state fermentation of Lactobacillus plantarum to degrade gossypol and enzymatic hydrolysis by neutral protease, which have antioxidant activity; Zein value: a core indicator for evaluating the skin irritation of surfactant systems; the lower the value, the less irritating.

[0027] All experiments in this invention were conducted in triplicate, and the results are expressed as mean ± standard deviation. All raw materials for daily chemical products meet the requirements of the "Safety Technical Specifications for Daily Chemical Products (2022 Edition)".

[0028] The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following specific embodiments.

[0029] Example 1 A method for preparing a citrus-scented detoxified cottonseed protein peptide facial cleanser includes the following steps: (1) The facial cleanser of the present invention is formulated by weight percentage as follows: deionized water balance, potassium cocoyl glycinate 25.0wt%, citric acid 1.3wt%, glycerin 30.0wt%, dipropylene glycol 5.0wt%, cocamidopropyl betaine 5.0wt%, decyl glucoside 5.0wt%, carbomer SF-1 3.0wt%, xanthan gum 0.4wt%, detoxified cottonseed protein peptide 1.0wt%, phenoxyethanol 0.9wt%, ethylhexylglycerin 0.1wt%, and citrus essential oil 0.4wt%.

[0030] (2) Under a 90℃ water bath, the surfactant system of potassium cocoyl glycinate, citric acid, cocamidopropyl betaine, decyl glucoside, humectant glycerin, dipropylene glycol and deionized water were mixed and stirred for 45 min to form a homogeneous system. (3) Add thickener Carbomer SF-1 and xanthan gum, and disperse and swell at 500 r / min for 10 min; (4) Cool down to 45°C, add detoxified cottonseed protein peptides, and ultrasonically disperse at 300 W for 5 min until uniform; (5) Cool down to 25°C, add citrus essential oil, preservatives phenoxyethanol and ethylhexylglycerin, stir evenly and let stand for 20 min to defoam, and obtain citrus-scented detoxified cottonseed protein peptide facial cleanser.

[0031] The method for preparing the detoxified cottonseed protein peptides mentioned above includes the following steps: (1) Using 60% cottonseed meal (protein content of 60%) as raw material, inoculate with Lactobacillus plantarum CICC 20315 ( Lactiplantibacillus plantarum CICC 20315 (strain purchased from China Industrial Microbial Culture Collection Center, strain number CICC 20315) was used for solid-state fermentation to remove gossypol, yielding detoxified cottonseed meal raw material; In this process, 10 mL of *Lactobacillus plantarum* seed solution was inoculated into every 100 g of cottonseed meal. The absorbance of the seed solution at 600 nm was 2.0. An appropriate amount of water was added to make the moisture content of the final fermentation mixture 50 wt%. Then, solid-state fermentation was carried out at 37 °C for 54 h to degrade gossypol and achieve detoxification of cottonseed meal. (2) The detoxified cottonseed meal raw material was crushed through 40 mesh, and washed with water and centrifuged at a ratio of 20 mL water per 1 g of cottonseed meal. This process was repeated 10 times, and then vacuum freeze-dried to obtain the washed detoxified cottonseed meal. (3) Neutral protease was used to enzymatically hydrolyze the washed detoxified cottonseed. Specifically, 20 mL of neutral protease aqueous solution was added to every 1 g of washed detoxified cottonseed meal. The neutral protease activity was 50,000 U / g, and the amount of neutral protease added based on the weight of cottonseed meal was 7 wt%. The enzyme was hydrolyzed at 45°C for 7 h, and the enzyme was inactivated at 95°C. The detoxified cottonseed protein peptides were obtained by centrifugation, concentration, and freeze drying. The performance indicators of the detoxified cottonseed protein peptides prepared in Example 1 were determined as follows: gossypol was not detected, and the crude protein content was 93.47%.

[0032] The method for preparing citrus essential oil described above includes the following steps: Place 300 g of freshly crushed citrus peel in a 1000 mL two-necked round-bottom flask, add 200 mL of distilled water, and then heat the flask in an oil bath at 160 °C. Simultaneously, continuously introduce steam into the bottom of the flask through one of the necks. Collect the steam containing essential oil that evaporates from the other neck using a condenser and allow it to settle and separate into layers. Stop distilling when the distillate changes from cloudy to clear. The collected upper clear yellow oily liquid is the citrus essential oil, which should be refrigerated and sealed for later use.

[0033] Example 2 A method for preparing a citrus-scented cottonseed protein peptide facial cleanser, the formula and preparation method are the same as in Example 1, except that the detoxified cottonseed protein peptide in Example 1 is replaced by 2.0wt% instead of 1.0wt%.

[0034] Example 3 A method for preparing a citrus-scented cottonseed protein peptide facial cleanser, the formula and preparation method are the same as in Example 1, except that the detoxified cottonseed protein peptide in Example 1 is replaced by 3.0 wt% instead of 1.0 wt%.

[0035] Example 4 A method for preparing a citrus-scented cottonseed protein peptide facial cleanser, the formula and preparation method are the same as in Example 1, except that the detoxified cottonseed protein peptide in Example 1 is replaced by 4.0 wt% instead of 1.0 wt%.

[0036] Example 5 A method for preparing a citrus-scented cottonseed protein peptide facial cleanser, the formula and preparation method are the same as in Example 1, except that the detoxified cottonseed protein peptide in Example 1 is replaced by 5.0 wt% instead of 1.0 wt%.

[0037] Example 6 A method for preparing a citrus-scented cottonseed protein peptide facial cleanser, the formula and preparation method are the same as in Example 2, except that the citrus essential oil in Example 2 is replaced from 0.4wt% to 0.2wt%.

[0038] Example 7 A method for preparing a citrus-scented cottonseed protein peptide facial cleanser, the formula and preparation method are the same as in Example 2, except that the citrus essential oil in Example 2 is replaced from 0.4wt% to 0.6wt%.

[0039] Example 8 A method for preparing a citrus-scented cottonseed protein peptide facial cleanser, the formula and preparation method are the same as in Example 2, except that the citrus essential oil in Example 2 is replaced from 0.4wt% to 0.8wt%.

[0040] Example 9 A method for preparing a citrus-scented cottonseed protein peptide facial cleanser, the formula and preparation method are the same as in Example 2, except that the citrus essential oil in Example 2 is replaced by 1.0 wt% instead of 0.4 wt%.

[0041] Comparative Example 1 The blank group had the same formulation and preparation method as in Example 1, except that the detoxified cottonseed protein peptide in Example 1 was replaced with 0.0wt% instead of 1.0wt%.

[0042] Comparative Example 2 The blank group had the same formulation and preparation method as Example 2, except that the citrus essential oil in Example 2 was replaced with 0.0wt% instead of 0.4wt%.

[0043] Test Example 1: Basic Physicochemical and Stability Tests The pH, heat resistance, cold resistance, thermal cycling, and centrifugal stability of the facial cleansers prepared in Examples 1-9 and Comparative Examples 1-2 were tested according to GB / T 29680-2013 and the "Safety Technical Specifications for Daily Chemical Products (2022 Edition)". The results are as follows: 1. pH value: The pH values ​​of all examples and comparative examples are 6.21 to 6.73, which are stable within the suitable range of slightly acidic skin (4.0–7.0). The products of this invention have no risk of skin irritation. Table 1. pH values ​​of facial cleansers from different embodiments and comparative examples. 2. Stability: Examples 1-9 and Comparative Examples 1-2 all passed the heat resistance test at 40℃, the cold resistance test at -8℃, three cycles of thermal cycling, and the centrifugation test at 2000 r / min. No stratification, water separation, clumping, or pearlescent damage were observed, indicating excellent system stability. The storage stability of the products of this invention meets the requirements for daily chemical products.

[0044] Table 2. Stability of facial cleansers from different embodiments and comparative examples. Test Example 2: Foam Performance Testing A 2.0% sample solution was prepared using hard water. The initial foam height and foam stability were tested using a Roche foam analyzer. The results are as follows: Figure 1 As shown in the figure. Compared with control group 1 (blank group), the addition of cottonseed protein peptides significantly improved the foam height and foam stability of the facial cleanser. The foam was finer and denser, and the foam height and foam stability increased with the increase of the proportion of detoxified cottonseed protein peptides. The addition of detoxified cottonseed protein peptides can significantly improve the foaming ability and foam stability of facial cleansing products. Figure 1 As shown in Comparative Examples 2, 2, and 6-9, the amount of citrus essential oil added has almost no effect on the foaming performance of the facial cleanser.

[0045] Example 3: Mildness assay (Zein protein method) The irritancy of the samples was evaluated using the Zein protein method, a common practice in the daily chemical industry. A 1% sodium dodecyl sulfate (SDS) solution was used as a positive control, and deionized water as a negative control. The zein solubility test was used to represent the irritancy of the facial cleanser. A diluted facial cleanser sample was used as the test substance. 1.0 g of the test substance and sodium dodecyl sulfate (SDS) were weighed and dissolved in deionized water to prepare a 1% (w / w) sample solution and a 1% SDS solution. Then, 0.35 g of zein was added to 20 mL of each of the above solutions, and the mixture was magnetically stirred at room temperature for 4 h or overnight. After the reaction, the mixture was centrifuged at 4500 rpm for 15 min, and the supernatant was further centrifuged at 12000 rpm for 15 min to obtain a clear supernatant. The supernatant from the SDS-treated group was diluted 50-fold with 1% SDS solution, and the supernatant from the sample-treated group was diluted 10-fold with the corresponding 1% sample solution. To establish a quantitative standard curve, weigh 20 mg of bovine serum albumin (BSA) and dissolve it in 800 mL of water. μ Prepare a 25 mg / mL BSA stock solution in L double-distilled water, then gradually dilute with 1% sample solution to obtain BSA standard solutions with concentrations of 0 mg / mL, 0.025 mg / mL, 0.05 mg / mL, 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, and 0.5 mg / mL. Finally, add 100 μL each of the standard solution and the diluted sample supernatant to a 96-well plate. μ L was measured for its absorbance at 280 nm using a microplate reader. A standard curve was plotted with absorbance at 280 nm as the x-axis and BSA protein concentration as the y-axis. The linear standard curve equation was obtained through linear regression analysis: y = 1.2372x + 0.0012, (R0...)0 2 =0.9993), such as Figure 2 As shown in the figure. The absorbance values ​​of the zein solution after sample treatment were substituted into the standard curve equation to calculate the zein concentration. The zein content of the zein was determined based on its zein value in the zein experiment, as shown in Table 3 below.

[0046] Table 3. Relationship between Zein value and irritation level The results are shown in Table 4. The citrus essential oil and detoxified cottonseed protein peptides of this invention can reduce the Zein value of the system, further improving the gentleness of the facial cleanser, with no skin irritation throughout the process.

[0047] Table 4. Mildness test results of facial cleansers from different examples and comparative examples. Example 4: Antioxidant Activity Assay Accurately weigh 1.0 g of facial cleanser sample, add an appropriate amount of distilled water to dissolve it completely, transfer it to a 10 mL volumetric flask and dilute to the mark, then vortex to mix. Centrifuge the resulting solution at 4800 r / min for 15 min, and take the supernatant for DPPH free radical (DPPH•) and ABTS free radical (ABTS) assays, respectively. + Free radicals (ABTS) + •) Determination of clearance rate.

[0048] (1) Determination of DPPH• scavenging rate Different groups of facial cleanser samples were mixed with an equal volume of 0.1 mmol / L DPPH anhydrous ethanol solution, with anhydrous ethanol as a blank control. The mixture was then reacted at room temperature in the dark for 30 min, and the absorbance was measured at a wavelength of 517 nm. Vitamin C was used as a positive control. The DPPH scavenging rate was calculated according to the following formula 1: In the formula, A0 is the absorbance value after DPPH and anhydrous ethanol are mixed; A1 is the absorbance value after the sample reacts with an equal volume of DPPH; and A2 is the absorbance value after the sample reacts with an equal volume of anhydrous ethanol.

[0049] (2) ABTS + • Determination of clearance rate Take 7 mmol / L ABTS + • Mix the aqueous solution with an equal volume of 2.45 mmol / L K2S2O8 solution until homogeneous, then let stand at room temperature in the dark for 16 h, and then dilute ABTS with anhydrous ethanol. + • Mix the solution until the absorbance at 734 nm is 0.70 ± 0.02. Take 0.2 mL of different groups of facial cleanser samples and add 5 mL of diluted ABTS. + • Mix the solution thoroughly and let it stand at room temperature in the dark for 30 min. Then measure its absorbance at a wavelength of 734 nm, using Vc as a positive control. Calculate ABTS according to the following formula 2. + • Clearance rate: (Equation 2) In the formula: A0 is the diluted ABTS + • Absorbance value of the mixture; A1 is the absorbance value of the sample solution at 734 nm wavelength; A2 is the absorbance value of undiluted ABTS. + • The absorbance value of the sample solution itself when mixed with the liquid.

[0050] The in vitro antioxidant activity of facial cleansers with different amounts of detoxified cottonseed protein peptides, for example... Figure 3 As shown.

[0051] Comparative Example 1: DPPH• and ABTS without added detoxified cottonseed protein peptides + • The clearance rates were only 43.27% and 37.53%, respectively, for DPPH and ABTS in Example 1. + • The clearance rates were increased to 60.64% and 66.28%, respectively, for DPPH and ABTS in Example 2. + • The clearance rates were further improved to 82.17% and 86.29%, respectively, in Example 5, DPPH and ABTS. + • The scavenging rates reached 92.27% and 94.33% respectively, indicating that the addition of detoxified cottonseed protein peptides enhances the antioxidant activity of the facial cleanser, and within a certain range, the antioxidant activity depends on the amount of detoxified cottonseed protein peptides added. When the amount of cottonseed protein peptides added is 2wt% and the amount of citrus essential oil added is 0.4wt%, the facial cleanser has strong free radical scavenging ability and strong antioxidant activity.

[0052] When the added amount of detoxified cottonseed protein peptides was fixed at 2wt%, the in vitro antioxidant activity of facial cleansers with different amounts of citrus essential oil added was as follows: Figure 4 This shows that citrus essential oil has significant DPPH• and ABTS. + • Scavenging ability and antioxidant activity. Comparative ratio 2 with DPPH and ABTS without added citrus essential oil. + • The free radical scavenging abilities were only 15.89% and 10.24% respectively; in Example 6, when the proportion of citrus essential oil added was only 0.2wt%, it showed that the facial cleanser product already had a certain free radical scavenging ability; as the amount of citrus essential oil added gradually increased to 1.0wt% (Example 9), the free radical scavenging ability of the product was further improved.

[0053] Example 5: Detection of Microbiological Hygiene Indicators The total bacterial count, Staphylococcus aureus, Escherichia coli, molds and yeasts, and Pseudomonas aeruginosa were tested according to the "Safety Technical Specifications for Daily Chemical Products (2022 Edition)," and the results are shown in Table 5. As can be seen from Comparative Example 2, Example 2, and Examples 6-9, when the amount of citrus essential oil added is not less than 0.4 wt% and the amount of detoxified cottonseed protein peptide added does not exceed 2 wt%, the total bacterial count of the product meets the requirement of not exceeding 1000 CFU / g as stipulated in the "Cosmetic Safety Technical Specifications," and the citrus essential oil has a significant antibacterial effect, the antibacterial ability depending on the amount of citrus essential oil added.

[0054] Table 5. Microbiological hygiene indicators of facial cleansers from different embodiments and comparative examples. Test Example 6: Cleaning Power and Human Trial Evaluation The makeup stain removal method was used for testing. In an experimental environment of 20℃ and 40% relative humidity, a 2.0 cm × 2.0 cm area was marked on the inner side of the subject's right arm as the sample control area and the test area, respectively. Oil-based pen ink and lipstick were applied, and 0.25 g of the test facial cleanser was applied to the stains, gently massaged for 1 minute, and then rinsed with water for 30 seconds. The cleaning effect was visually observed, and the results are shown in Table 6. Compared with Comparative Examples 1 and 2, Examples 1-9 showed good cleaning effects on lipstick and oil-based pen ink stains, with extremely low residue and a high level of cleaning power. The addition of cottonseed protein peptides and citrus essential oils helped to improve the cleaning ability of the facial cleanser.

[0055] Table 6. Cleansing power of facial cleansers for pen ink and lipstick in different embodiments and comparative examples. The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing detoxified cottonseed protein peptides, characterized in that, Includes the following steps: S1. Using cottonseed meal as raw material, inoculate with Lactobacillus plantarum for solid-state fermentation to remove gossypol and obtain detoxified cottonseed meal raw material; S2. The detoxified cottonseed meal is enzymatically hydrolyzed with neutral protease to obtain detoxified cottonseed protein peptides.

2. The preparation method according to claim 1, characterized in that, In S1, the protein content of the cottonseed meal is 60%, the inoculation amount of *Lactobacillus plantarum* is 8-12%, the ratio of cottonseed meal to water is 10 g: 4-6 mL, and the fermentation conditions include: fermentation temperature of 28-39℃ and fermentation time of 50-70 h.

3. The preparation method according to claim 1, characterized in that, In S2, the ratio of cottonseed meal to neutral protease aqueous solution is 1 g: 15~25 mL, and the amount of neutral protease added is 6~8 wt% of the cottonseed meal mass. The enzymatic hydrolysis conditions include: enzymatic hydrolysis temperature of 40~60℃ and enzymatic hydrolysis time of 5~12 h.

4. A detoxified cottonseed protein peptide, characterized in that, It is obtained by the preparation method described in any one of claims 1 to 3.

5. The application of the detoxified cottonseed protein peptide according to claim 4 in the preparation of non-irritating, fragrant external cleaning daily chemical products.

6. A facial cleanser containing cottonseed protein peptides, characterized in that, Its composition, based on 100% by weight, includes: Detoxified cottonseed protein peptides 1.0~5.0wt%; Fragrance-enhancing essential oils: 0.2wt%–1.0wt%; Surfactant system 10wt%~40wt%; Moisturizer 10wt%~40wt%; Thickener 0.1wt%~5.0wt%; Preservatives: 0.1 wt%–1.1 wt%; Deionized water balance.

7. The facial cleanser containing cottonseed protein peptides according to claim 6, characterized in that, The flavoring essential oil is citrus essential oil, which is extracted from citrus peel by steam distillation. The surfactant system is a compound of amino acid-based surfactants, amphoteric surfactants, and nonionic surfactants, specifically consisting of 25.0 wt% potassium cocoyl glycinate, 5.0 wt% cocamidopropyl betaine, and 5.0 wt% decyl glucoside. The moisturizers are glycerin 30.0 wt% and dipropylene glycol 5.0 wt%. The thickeners are 3.0 wt% carbomer SF-1 and 0.4 wt% xanthan gum. The preservatives are 0.9 wt% phenoxyethanol and 0.1 wt% ethylhexylglycerin.

8. The facial cleanser containing cottonseed protein peptides according to claim 7, characterized in that, The method for extracting the citrus essential oil includes: Freshly crushed citrus peels are placed in a reaction vessel with two feeding ports, distilled water is added, and the vessel is heated in an oil bath at 150-170°C. Simultaneously, steam is continuously introduced into the bottom of the flask through one feeding port. The steam containing essential oil that evaporates from the other feeding port is collected by a condenser and allowed to stand and separate into layers. Distillation is stopped when the distillate changes from turbid to clear. The clear yellow oily liquid collected on the upper layer is citrus essential oil. The ratio of citrus peel to distilled water is 30g: 15~25mL.

9. The method for preparing the facial cleanser containing cottonseed protein peptides according to any one of claims 6 to 8, characterized in that, Includes the following steps: (1) Under the conditions of 85~95℃ water bath, the surfactant system, humectant and deionized water are mixed and stirred for 40~50 min to form a homogeneous system; (2) Add thickener and disperse and swell at high speed of 300~500 r / min for 5~15 min; (3) Cool down to 40~50℃, add the detoxified cottonseed protein peptide, and ultrasonically disperse at 250~350 W for 3~7 min until uniform; (4) Cool the mixture to 20-30 °C, add fragrance-enhancing essential oils and preservatives, stir well and let it stand for 15-20 min to remove bubbles, and obtain the facial cleanser containing cottonseed protein peptides.

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