Collagen-amino acid-based composite surfactant and preparation method thereof

Abstract

The invention discloses a composite surfactant based on collagen-amino acid and a preparation method thereof, and belongs to the technical field of biological materials and daily chemicals. Through a strategy of amino acid bridging and accurate acyl chloride modification, the problems of poor hydrophobicity of recombinant collagen, low biocompatibility of a traditional surfactant and the like are successfully solved, and while the activity of natural protein is maintained, the recombinant collagen is endowed with interface performance comparable with that of a chemical surfactant. The technology disclosed by the invention can be widely applied to the fields of high-added-value medicines, cosmetics and functional foods, and has remarkable market competitiveness.

Description

Technical Field

[0001] This invention relates to a collagen-amino acid-based composite surfactant and its preparation method, belonging to the field of biomaterials and daily chemical products technology. Background Technology

[0002] Traditional surfactants, such as SLS (sodium lauryl sulfate) and SLES (sodium laureth sulfate), while possessing excellent cleansing properties, are extremely damaging to the skin barrier. Long-term use can easily lead to dry skin, sensitivity, and even allergic reactions, severely impacting the user experience and skin health. Meanwhile, natural collagen extracts, due to their large molecular weight, have difficulty effectively penetrating the skin barrier, resulting in poor transdermal absorption and limiting their application in cosmetics and drug delivery systems. Furthermore, animal-derived collagen poses a potential immunogenicity risk, which may trigger an immune response, further restricting its application scope.

[0003] The application of surfactants in combination with proteins also faces technical challenges. When protein molecules are directly added to surfactant systems, they are prone to denaturation, aggregation, and precipitation, resulting in a significant loss of their biological activity and an inability to perform the expected repair and moisturizing functions. While existing amino acid surfactants, such as sodium cocoyl glycinate, balance cleansing power and gentleness to some extent, they still cannot simultaneously meet the dual needs of efficient cleansing and skin repair, thus failing to provide consumers with a comprehensive skincare solution.

[0004] Therefore, the preparation of a surfactant based on proteins and its use in the preparation of personal care products, which can simultaneously meet the dual needs of efficient cleaning and skin repair, has extremely high practical and economic value. Summary of the Invention

[0005] To address the aforementioned problems, this invention employs a strategy involving collagen, amino acid bridging, and precise modification with acyl chlorides. This successfully solves issues such as poor protein hydrophobicity and low biocompatibility of traditional surfactants, maintaining the activity of natural proteins while endowing them with interfacial properties comparable to those of chemical surfactants. The technical solution of this invention can be widely applied in the fields of high-value-added pharmaceuticals, cosmetics, and functional foods, possessing significant market competitiveness.

[0006] The first objective of this invention is to provide a method for preparing a collagen-amino acid composite surfactant, comprising the steps of: (1) Mix collagen with amino acids, disperse in deionized water, and stir to obtain a colloidal solution system; (2) Add acyl chloride dropwise to the colloidal solution system, and continue the reaction for 2-6 h after the addition is complete; (3) After the reaction is complete, filter the filter cake and dry the filter cake to obtain collagen-amino acid composite surfactant powder; The ratio of collagen, amino acids, and acyl chloride used is 1~5 kg: 5~15 kg: 7.5~15 L; The molecular weight of collagen is 3 kDa to 100 kDa; the amino acid is any one of glycine, serine, glutamic acid, sarcosine, aspartic acid, and alanine; the acyl chloride is any one of capryloyl chloride, lauroyl chloride, myristoyl chloride, soybean oleyl chloride, isostearyl chloride, and cocoyl chloride.

[0007] Optionally, in one embodiment, the molecular weight of the collagen is 3 kDa, 50 kDa, or 100 kDa.

[0008] In one embodiment, the ratio of collagen, amino acids, and water used in step (1) is 6~20 kg: 10~50 L.

[0009] In one embodiment, the ratio of collagen water used is 1~5 kg: 10~50 L.

[0010] Optionally, the amino acid in step (1) is any one of glycine, serine, or aspartic acid.

[0011] In one embodiment, the stirring in step (1) is carried out at 20~25 ℃ and 600~800 rpm for 30~40 min.

[0012] In one embodiment, step (2) is performed by adding dropwise at pH 8.5~10.5 and 5~25 °C.

[0013] In one embodiment, the dropping rate of acyl chloride in step (2) is 41.67~250 mL / min; Optionally, the dropping rate is 100~200 mL / min.

[0014] Optionally, the acyl chloride in step (2) is lauroyl chloride.

[0015] In one embodiment, the reaction temperature in step (2) is 5~25 °C; Optionally, when the collagen molecular weight is 50 kDa and the amino acid is glycine, the reaction temperature in step (2) is 15°C; Optionally, when the collagen molecular weight is 3 kDa and the amino acid is serine, the reaction temperature in step (2) is 25°C; Optionally, when the collagen molecular weight is 100 kDa and the amino acid is aspartic acid, the reaction temperature in step (2) is 5 °C.

[0016] In one embodiment, drying in step (3) refers to vacuum or forced-air drying at 40°C to 60°C.

[0017] A second object of the present invention is to provide a collagen-amino acid composite surfactant prepared by any of the above methods.

[0018] A third objective of this invention is to provide the application of any of the above-described methods or the above-described collagen-amino acid complex surfactants in the preparation of daily chemical products.

[0019] A fourth objective of this invention is to provide a personal care product containing the aforementioned protein-amino acid complex surfactant; The personal care products include shampoo, conditioner, facial cleanser, and shower gel.

[0020] The fifth objective of this invention is to provide a method for simultaneously improving the surface tension, emulsifying activity, and foaming properties of a protein-amino acid composite surfactant, comprising the steps of: (1) Mix collagen with amino acids, disperse in deionized water, and stir to obtain a colloidal solution system; (2) Add acyl chloride dropwise to the colloidal solution system, and continue the reaction for 2-6 h after the addition is complete; (3) After the reaction is complete, filter the filter cake and dry the filter cake to obtain collagen-amino acid composite surfactant powder; The ratio of collagen, amino acids, and acyl chloride used is 1~5 kg: 5~15 kg: 7.5~15 L; The molecular weight of collagen is 3 kDa to 100 kDa; the amino acid is any one of glycine, serine, glutamic acid, sarcosine, aspartic acid, and alanine; the acyl chloride is any one of capryloyl chloride, lauroyl chloride, myristoyl chloride, soybean oleyl chloride, isostearyl chloride, and cocoyl chloride.

[0021] Optionally, in one embodiment, the molecular weight of the collagen is 3 kDa, 50 kDa, or 100 kDa.

[0022] In one embodiment, the ratio of collagen, amino acids, and water used in step (1) is 6~20 kg: 10~50 L.

[0023] In one embodiment, the ratio of collagen water used is 1~5 kg: 10~50 L.

[0024] Optionally, the amino acid in step (1) is any one of glycine, serine, or aspartic acid.

[0025] In one embodiment, the stirring in step (1) is carried out at 20~25 ℃ and 600~800 rpm for 30~40 min.

[0026] In one embodiment, step (2) is performed by adding dropwise at pH 8.5~10.5 and 5~25 °C.

[0027] In one embodiment, the dropping rate of acyl chloride in step (2) is 41.67~250 mL / min.

[0028] Optionally, the dropping rate is 100~200 mL / min.

[0029] Optionally, the acyl chloride in step (2) is lauroyl chloride.

[0030] In one embodiment, the reaction temperature in step (2) is 5~25 °C; Optionally, when the collagen molecular weight is 50 kDa and the amino acid is glycine, the reaction temperature in step (2) is 15°C; Optionally, when the collagen molecular weight is 3 kDa and the amino acid is serine, the reaction temperature in step (2) is 25°C; Optionally, when the collagen molecular weight is 100 kDa and the amino acid is aspartic acid, the reaction temperature in step (2) is 5 °C.

[0031] In one embodiment, drying in step (3) refers to vacuum or forced-air drying at 40°C-60°C.

[0032] Beneficial effects of the present invention This invention successfully solves the problems of poor hydrophobicity of collagen and low biocompatibility of traditional surfactants by employing a strategy of collagen, amino acid bridging, and precise modification with acyl chlorides. While maintaining the activity of natural collagen, it endows it with interfacial properties comparable to those of chemical surfactants. The technical solution of this invention can be widely applied in the fields of high-value-added pharmaceuticals, cosmetics, and functional foods, and has significant market competitiveness.

[0033] Specifically, (1) The modified compound system can reduce the surface tension of the aqueous solution to 26.3~29.3 mN / m (58.2 mN / m for unmodified collagen), which is close to the performance of traditional synthetic surfactants (such as SDS).

[0034] (2) The emulsification index (EAI) of liquid paraffin reached 86%, and the emulsion stability was significantly better than that of physical mixing systems (layering time >30 days compared with <15 days of traditional protein emulsifiers).

[0035] (3) The reaction conditions are mild. The modification can be completed at 5~25℃ and pH 8.5~10.5, avoiding the destruction of protein structure by high temperature / strong acid.

[0036] (4) No toxic residues. Compared with the EDC / NHS cross-linking method and organic solvent synthesis method, no subsequent purification is required to remove catalysts and organic solvents, which meets the cosmetic standards. Attached Figure Description

[0037] Figure 1 The infrared spectral detection results of the collagen-glycine composite surfactant in Example 1 are shown below. Figure 2 The results of the irritation test (solubility of zein) of the collagen-glycine composite surfactant prepared in Example 1 are shown. Detailed Implementation

[0038] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0039] Raw materials used in the examples: Collagen (3 kDa, 50 kDa, 100 kDa) was purchased from Jiangsu Chuangjian Medical Technology Co., Ltd. Cocoyl chloride was purchased from Shandong Gaotai Chemical Technology Co., Ltd. Octanoyl chloride was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Lauroyl chloride was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. The amino acids were purchased from Shanghai Haohong Biomedical Technology Co., Ltd.

[0040] Test method: 1. Surface tension The surface activity of the modified collagen products in Examples 1, 2, and 3 was systematically evaluated using the Wilhelmy plate method. The specific steps are as follows: First, the products of each example were accurately weighed and prepared into an aqueous solution with a concentration of 0.1% (w / v). After being fully dissolved by a magnetic stirrer, the solution was transferred to a constant temperature bath and allowed to stand for 30 minutes at 25℃±0.1℃ to eliminate the influence of temperature gradient on surface tension. Subsequently, the surface tension was measured using a fully automated surface tension meter (K100 type). A platinum sheet (contact angle ≈0°) was slowly immersed in the solution until it was completely wetted. After the instrument reading stabilized, the equilibrium surface tension value was recorded. Each sample was measured three times and the arithmetic mean was taken to eliminate random errors. Finally, by comparing the surface tension data of the products of each example, the influence of molecular structure modification on interfacial adsorption behavior and interfacial energy reduction ability can be quantitatively analyzed.

[0041] 2. Emulsifying activity and stability (EAI / ESI index) Weigh the surfactant solution and liquid paraffin at a mass ratio of 1:4 (e.g., 0.8 g surfactant solution + 3.2 g liquid paraffin). Vortex mix for 30 s to form an emulsion. Take 0.1 mL of the emulsion and dilute it to 10 mL with distilled water (dilution factor N=100). After standing for 10 min, using distilled water as a blank, measure the absorbance A0 at 500 nm. Substitute into the formula to calculate EAI. Transfer the emulsion to a centrifuge tube and let it stand for 0.5 h, 1 h, 2 h, and 4 h. Each time, take 0.1 mL of the upper layer of the emulsion, dilute it, and measure the absorbance A. t .

[0042] 3. Foam performance (Ross-Miles method) The experimental method for determining foam performance using a Roche foam analyzer is as follows: First, turn on the thermostat of the Roche foam analyzer and wait for its temperature to stabilize at 40℃±0.5℃. Then, thoroughly rinse the inner wall of the graduated tube with distilled water, and then rinse the tube wall with a test solution preheated to 40℃. Close the graduated tube stopcock and inject 50 mL of the test solution preheated to 40℃ to the 50 mL mark. At the same time, fill the dropper with 200 mL of the test solution preheated to 40℃. Place the dropper on the tube rack and perpendicular to the cross-section of the graduated tube, ensuring that the outlet of the dropper is at the 900 mm mark. Then, open the stopcock to allow the solution to flow freely. When the solution in the dropper has flowed out, immediately start the stopwatch and record the initial foam height. Record the foam height every 5 minutes from 0 to 30 minutes. The foam performance is represented by the foam height value. The experiment needs to be repeated 2-3 times. Before each experiment, the inner wall of the instrument must be thoroughly cleaned to avoid residue affecting the accuracy of the data.

[0043] 4. Cell viability retention rate The MTT (3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide) method is a classic cell proliferation / toxicity assay that indirectly reflects cell number and viability by detecting the ability of mitochondrial dehydrogenases in living cells to reduce MTT to formazan.

[0044] Take fibroblasts in the logarithmic growth phase and adjust the density (5×10⁻⁶). 3 ~1×10 4 (cells / well, 96-well plate); add 100 μL of complete culture medium to each well and incubate for 24 h to allow cells to adhere; Experimental Groups: Blank control group (culture medium only, no cells); Negative control group (untreated cells); Experimental group (samples of different concentrations); Positive control group (e.g., 10% FBS or PDGF stimulation); Add 10 μL of MTT solution (5 mg / mL, prepared in PBS) to each well (final concentration 0.5 mg / mL); incubate at 37 °C for 4 h, then discard the supernatant; add 100-150 μL of DMSO to each well and shake slowly for 10 min to dissolve the crystals; measure the absorbance at 490 nm using a microplate reader.

[0045] The formula for calculating cell viability retention rate is as follows: Cell viability (%) = (OD value of experimental group - OD value of blank group) / (OD value of control group - OD value of blank group) × 100% Example 1: Preparation of amino acid-protein based composite surfactant 1. Preparation of amino acid-protein based composite surfactants, including the following steps: (1) Mix 5 kg of collagen (50 kDa) and 15 kg of glycine, dissolve them in 50 L of deionized water at 25°C, and stir mechanically at 800 rpm for 30 min to form a homogeneous colloidal solution system. (2) Under pH 9.5 conditions, 15 L of lauroyl chloride was slowly added dropwise to the colloidal solution system at a constant rate of 125 mL / min. The reaction temperature was maintained at 15 ℃ ± 0.5 ℃ in an ice-water bath. After the addition was completed, the reaction was stirred for 4 h to ensure that the acylation reaction was complete. (3) After the reaction is complete, filter cake is obtained by filtration. The filter cake is dried by blowing at 50 °C to obtain collagen-glycine composite surfactant powder.

[0046] 2. Infrared spectroscopy detection The infrared spectral detection results of the collagen-glycine composite surfactant are as follows: Figure 1 As shown, the results indicate that the modified product is at 1720 cm⁻¹ -1 (Ester bond) and 1640 cm -1 The appearance of a characteristic peak at the (amide I band) indicates that a stable acylation structure has been successfully constructed.

[0047] Example 2: Preparation of amino acid-protein based composite surfactants The preparation of amino acid-protein based composite surfactants includes the following steps: (1) Mix 1 kg of collagen (3 kDa) and 5 kg of serine, dissolve them in 10 L of deionized water at 25°C, and stir mechanically at 800 rpm for 35 min to form a homogeneous colloidal solution system. (2) Under pH 8.5 conditions, 7.5 L of lauroyl chloride was slowly added dropwise to the colloidal solution system at a constant rate of 62.5 mL / min. The reaction temperature was maintained at 25℃±0.5℃ in an ice-water bath. After the addition was completed, the reaction was stirred for 4 h to ensure that the acylation reaction was complete. (3) After the reaction is complete, filter cake is obtained by filtration. The filter cake is dried under vacuum at 40 °C to obtain collagen-serine composite surfactant powder.

[0048] Example 3: Preparation of amino acid-protein based composite surfactants The preparation of amino acid-protein based composite surfactants includes the following steps: (1) Mix 3 kg of collagen (100 kDa) and 10 kg of aspartic acid, dissolve them in 25 L of deionized water at 25°C, and stir mechanically at 800 rpm for 40 min to form a homogeneous colloidal solution system. (2) Under pH 10.5 conditions, 11 L of lauroyl chloride was slowly added dropwise to the colloidal solution system at a constant rate of 91.7 mL / min. The reaction temperature was maintained at 5℃±0.5℃ in an ice-water bath. After the addition was completed, the reaction was stirred for 4 h to ensure that the acylation reaction was complete. (3) After the reaction is complete, filter the filter cake and dry it at 60 °C to obtain collagen-aspartic acid composite surfactant powder.

[0049] Comparative Example 1: Changing the reaction temperature Based on Example 1, the reaction temperature of step (2) was changed to 30°C, and the remaining steps were the same as in Example 1.

[0050] Comparative Example 2: Changing the preparation steps Based on Example 1, the preparation steps were modified as follows: (1) Dissolve 5 kg of collagen (50 kDa) and 15 kg of glycine in 30 L and 20 L of deionized water, respectively, and make both systems clear and transparent by gentle stirring and ultrasonic assistance; (2) At pH 9.5, 7.5 L of lauroyl chloride was slowly added dropwise to the collagen solution system at a constant rate of 62.5 mL / min using a constant pressure dropping funnel. At the same time, 7.5 L of lauroyl chloride was slowly added dropwise to the glycine system under the same conditions. The entire reaction was carried out at 10℃±0.5℃. After the addition was completed, both reactions continued for 4 hours. (3) After the reaction is completed, filter cakes are obtained by filtration. The filter cakes are dried by blowing at 50 °C to obtain two powders: collagen-based surfactant and amino acid surfactant. The products are then mixed to obtain a mixed surfactant.

[0051] Comparative Example 3: Changing the dosage ratio (1) Based on Example 1, the ratio of collagen to lauroyl chloride was changed to 5 kg: 7 L, and the remaining steps were the same as in Example 1.

[0052] (2) Based on Example 1, the ratio of collagen to lauroyl chloride was changed to 5 kg: 15.5 L, and the remaining steps were the same as in Example 1.

[0053] Comparative Example 4: Using other acyl chlorides Based on Example 1, lauroyl chloride was changed to octanoyl chloride and cocoyl chloride respectively, and the remaining steps were the same as in Example 1.

[0054] Comparative Example 5: Using other amino acids Based on Example 1, glycine was replaced with glutamic acid, sarcosine, alanine, and proline, respectively, while the remaining steps were the same as in Example 1.

[0055] Comparative Example 6: Changing the Synthesis Conditions 1. EDC / NHS crosslinking method (1) Collagen pretreatment Dissolving collagen: Dissolve collagen in 0.1 M acetic acid (stirring at 4°C for 12 h) to a concentration of 5 mg / mL.

[0056] Adjust pH: Dilute the collagen solution with MES buffer (pH 5.5) to ensure carboxyl grouping (-COOH form, which is beneficial for EDC activation).

[0057] (2) EDC / NHS activates carboxyl groups Add EDC / NHS: EDC:COOH = 2:1 (approximately 0.5 mg EDC is needed for 1 mg of collagen); NHS:EDC = 1:2 (1 mg EDC corresponds to 2 mg NHS); Add EDC / NHS solution (dissolved in MES) dropwise under ice bath conditions and stir for 30 min (4℃) in the dark.

[0058] (3) Amino acid coupling Add amino acids: Dissolve glycine in a small amount of DMSO, then dilute to PBS (pH 7.4). Amino acids: activated collagen = 77:3 (molar ratio), stirred at room temperature for 8 h; To terminate the reaction, add ethanolamine to block the unreacted NHS ester and stir for 1 h.

[0059] (4) Purified product Dialysis purification: Deionized water was dialyzed (4℃, 48 h, MWCO 300 Da) to remove uncoupled amino acids and byproducts.

[0060] Freeze-drying preservation: collagen-amino acid surfactant powder is obtained by freeze-drying.

[0061] 2. Organic solvent synthesis method The preparation method of amino acid-collagen complex surfactant using organic solvent (water-acetone) and lauroyl chloride is as follows: First, collagen and amino acid powders are dissolved in a water-acetone mixed solvent (volume ratio 1:2, pH adjusted to 9.5), and cooled to 4°C in an ice bath; then lauroyl chloride (molar ratio of free collagen amino to lauroyl chloride = 1:2) is slowly added dropwise while stirring continuously, and the pH is maintained at 9.0 (0.1 M NaOH is added using an automatic titrator); after the reaction is carried out under nitrogen protection for 6 hours, ice-cold acetone is added to terminate the reaction and precipitate the product. The precipitate is collected by centrifugation and washed three times with acetone to remove unreacted lauroyl chloride; finally, the product is redissolved in 0.1 M acetic acid solution, dialyzed (MWCO 300 Da) for 48 hours to remove small molecule byproducts, and lyophilized to obtain a white flocculent collagen-lauroyl amino acid surfactant.

[0062] Example 5: Surfactant Performance Testing 1. Surfactant surface tension, emulsifying activity and stability (EAI / ESI index), and foaming properties (Ross-Miles method) The surfactants prepared in Examples 1-4 and Comparative Examples 1-6 were tested for their properties, and the results are shown in Table 1.

[0063] Table 1 Surfactant Properties

[0064] The results show that the protein-amino acid composite surfactants prepared in Examples 1-3 of this invention possess excellent comprehensive performance. Their surface tension (26.3-29.3 mN / m), emulsifying activity (EAI 80-86 m² / g), emulsifying stability (ESI 80-85%), and foaming properties (initial foam height 148-160 mm, 30-minute height 75-85 mm) are significantly superior to unmodified collagen, and comparable to or even better than commercially available traditional surfactants such as SDS and APG. Example 1 exhibits the best performance combination, achieving a 30-minute foam height of 85 mm, significantly better than commercially available products. The performance parameters of the comparative examples are generally lower than those of the example group, confirming that the specific protein-amino acid combination and ratio of this invention have a significant synergistic effect.

[0065] 2. Stimulation test Products with stronger irritant properties dissolve zein more easily than those with weaker irritant properties. The amount of zein that can be dissolved per gram of different products was determined by weighing. Specific operating steps are as follows: Weigh an excess of zein and add it to the composite surfactant of Examples 1-3 at a mass fraction of 1%. Vortex for 20 minutes and magnetically stir for 2 hours to dissolve, ensuring thorough mixing of the zein and solution. Filter the solution and calculate the amount of zein dissolved. The results are as follows: Figure 2 As shown.

[0066] The results showed that, compared with the solubility of zein by traditional surfactants, the collagen-amino acid composite surfactants prepared in Examples 1-3 had significantly lower solubility in zein, weaker interaction with zein, and lower skin irritation.

[0067] 3. Stability testing The collagen-amino acid composite surfactant solutions with a mass fraction of 5% prepared in Examples 1-3 and Comparative Examples 2-4 and 6 were subjected to accelerated aging tests under two conditions: a high-temperature and high-humidity (40℃ / 75% RH) constant temperature and humidity chamber and a freeze-thaw cycle (alternating between -20℃ and 25℃, with one cycle completed every 24 hours). The steps are as follows: Samples were aliquoted into sealed aluminum foil bags, with three parallel samples in each group. Samples were taken and tested at three time points: 0, 1, and 3 months. The high temperature and high humidity group used a dynamic humidity control system to maintain the environmental parameter fluctuation range within ≤±2%. The freeze-thaw group used a programmable temperature controller to achieve a temperature conversion rate of ≥5℃ / min to simulate extreme conditions in actual storage / transportation. The results are shown in Table 2.

[0068] Table 2 Stability test results

[0069] The results showed that the collagen-amino acid composite surfactants prepared in Examples 1-3 did not exhibit performance degradation after 3 months at 40℃ / 75%RH, and still maintained 95% cell viability after freeze-thaw cycles.

[0070] 4. Validation in large-scale production A systematic pilot-scale amplification verification was carried out in a 100 L stainless steel reactor, and the steps are as follows: (1) Increase the amount of raw materials by proportion, increase the amount of key components (such as glycine, collagen, etc.) in Example 1 by ten times and transfer them precisely to a 100 L reactor, and use an online weighing system to monitor the feeding accuracy in real time (error ≤ ±0.5%). (2) The reaction temperature was precisely controlled (15℃±0.5℃) in the reactor through the jacketed circulating water system, and the mechanical stirrer (200 rpm) was turned on for 240 min to maintain solution homogenization. Then, 30 L of lauroyl chloride reagent (corresponding to the expansion ratio) was added dropwise to the reaction system at a constant flow rate (250 mL / min) using a peristaltic pump. During the dropwise addition, the pH online monitoring system was turned on simultaneously, and the alkali solution was automatically added by a micro pump to maintain the pH in the range of 9.0~10.0. The reaction process was monitored by taking samples at regular intervals through a headspace sampler and analyzing them by HPLC (the endpoint was when the conversion rate of the target product was ≥95%). (3) After the reaction is complete, filter, 50 o The final product was obtained by drying the filter cake with a forced air filter. Pilot-scale results showed that the product yield (87.2%) in the 100L reactor scale-up was comparable to that in the small-scale process (89.1%). Furthermore, the surface tension measurement (Wilhelmy plate method) verified that the key quality attributes such as molecular weight distribution and emulsification performance were highly consistent with the small-scale product, laying a technical foundation for subsequent upgraded production.

[0071] The surface tension deviation and emulsification index results of the three batches (batch 1 to 3 corresponding to Example 1) are shown in Table 3. The results show that the surface tension deviation of the three batches is <1.5 mN / m.

[0072] Table 3 Surface tension, emulsification index

[0073] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for preparing a collagen-amino acid composite surfactant, characterized in that, Including the following steps: (1) Mix collagen with amino acids, disperse in deionized water, and stir to obtain a colloidal solution system; (2) Add acyl chloride dropwise to the colloidal solution system, and continue the reaction for 2-6 h after the addition is complete; (3) After the reaction is complete, filter the filter cake and dry the filter cake to obtain collagen-amino acid composite surfactant powder; The ratio of collagen, amino acids, and acyl chloride used is 1~5 kg: 5~15 kg: 7.5~15 L; The molecular weight of collagen is 3 kDa to 100 kDa; the amino acid is any one of glycine, serine, glutamic acid, sarcosine, aspartic acid, and alanine; the acyl chloride is any one of capryloyl chloride, lauroyl chloride, myristoyl chloride, soybean oleyl chloride, isostearyl chloride, and cocoyl chloride.

2. The method according to claim 1, characterized in that, In step (1), the ratio of collagen and amino acids mixed with water is 6~20 kg: 10~50 L; Optionally, the amino acid in step (1) is any one of glycine, serine, or sarcosine.

3. The method according to claim 1, characterized in that, In step (1), the stirring is carried out at 20~25 ℃ and 600~800 rpm for 30~40 min.

4. The method according to claim 1, characterized in that, In step (2), the addition is carried out at pH 8.5~10.5 and 5~25 ℃. Optionally, the acyl chloride in step (2) is lauroyl chloride; Optionally, in step (2), the addition is performed dropwise at pH 9.

5.

5. The method according to claim 1, characterized in that, In step (2), the dropping rate of acyl chloride is 41.67~250 mL / min; Optionally, the dropping rate is 100~200 mL / min.

6. The method according to claim 1, characterized in that, In step (3), drying refers to vacuum or forced-air drying at 40℃~60℃.

7. The collagen-amino acid composite surfactant prepared by the method according to any one of claims 1 to 6.

8. The application of the method according to any one of claims 1 to 6 or the collagen-amino acid composite surfactant according to claim 7 in the preparation of daily chemical products.

9. A personal care product, characterized in that, The washing and care products contain the collagen-amino acid complex surfactant as described in claim 7; Optionally, personal care products include shampoo, conditioner, facial cleanser, and shower gel.

10. A method for simultaneously improving the surface tension, emulsifying activity, and foaming properties of a collagen-amino acid composite surfactant, characterized in that, Including the following steps: (1) Mix collagen with amino acids, disperse in deionized water, and stir to obtain a colloidal solution system; (2) Add acyl chloride dropwise to the colloidal solution system, and continue the reaction for 2-6 h after the addition is complete; (3) After the reaction is complete, filter the filter cake and dry the filter cake to obtain collagen-amino acid composite surfactant powder; The ratio of collagen, amino acids, and acyl chloride used is 1~5 kg: 5~15 kg: 7.5~15 L; The molecular weight of collagen is 3 kDa to 100 kDa; The amino acid is any one of glycine, serine, glutamic acid, sarcosine, aspartic acid, and alanine; the acyl chloride is any one of capryloyl chloride, lauroyl chloride, myristoyl chloride, soybean oleyl chloride, isostearyl chloride, and cocoyl chloride. Optionally, in step (1), the ratio of collagen and amino acids mixed with water is 6~20 kg: 10~50 L; Optionally, the amino acid in step (1) is any one of glycine, serine, or sarcosine; Optionally, the dropping rate of acyl chloride in step (2) is 41.67~250 mL / min; or, the dropping rate is 100~200 mL / min. Optionally, the acyl chloride in step (2) is lauroyl chloride.

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