Microemulsified vegetable soap containing active ingredients of moringa seeds and method for its preparation

Abstract

This invention discloses a microemulsified plant soap containing moringa seed active ingredients and its preparation method. The plant soap comprises, by weight percentage, 40-70% soap base, 8-18% moringa seed oil, 0.5-3.0% moringa seed protein extract, 4-10% a non-soap-based surfactant system, 5-15% polyol, and the balance being water. Moringa seed oil is rich in oleic acid and has a low peroxide value, thus delaying oil auto-oxidation. The moringa seed protein extract is rich in small molecule peptides, which can form a stable protective layer at the oil-water interface, improving the stability of oil droplets. This microemulsified plant soap exhibits strong antioxidant properties, long-lasting effect, and skin-friendly properties.

Description

Technical Field

[0001] This invention relates to the technical field of Moringa seed plant soap, and in particular to a microemulsified plant soap containing active ingredients from Moringa seeds and its preparation method. Background Technology

[0002] The pods and seeds of Moringa plants are rich in various lipids, proteins, and small-molecule active ingredients. The pod oil contains a high proportion of essential polyunsaturated fatty acids, while the small-molecule peptides in Moringa seed protein and its hydrolysate show promising applications in interfacial stabilization, moisturizing, and skin barrier conditioning. In recent years, Moringa pod oil and Moringa seed protein have been increasingly used in cleansing and skincare products to enhance skin gentleness, moisturizing ability, and antioxidant properties.

[0003] In solid soap products, the use of vegetable oils and proteins as active ingredients still faces limitations in structural stability. Solid soap base systems are typically weakly alkaline, with high solid content and a dense internal network structure. Unsaponified oils and proteins are difficult to achieve stable and fine dispersion within the soap body, often existing as large oil droplets or locally enriched phases. During use and storage, active lipids are affected by oxygen, metal ions, and residual alkaline sites, leading to oxidation reactions. Proteins and small peptides are also prone to degradation or inactivation under alkaline conditions, resulting in a darker soap color, decreased transparency, off-odors, and reduced retention of active ingredients.

[0004] While naturally sourced Moringa pod oil contains a certain proportion of polyunsaturated fatty acids, its native oil may also contain volatile sulfur compounds and other components that are unsuitable for skin application, requiring effective removal during the refining process. Furthermore, oils with high polyunsaturated fatty acid content are more prone to oxidation chain reactions in an alkaline soap environment, making it more difficult for unsaponifiable oils to maintain a transparent and stable dispersion in the soap.

[0005] Therefore, how to maintain the structural stability of active ingredients such as moringa pod oil, moringa seed oil, and moringa seed protein in solid plant soap systems, and how to quickly form a dispersion system with fine particle size, high transparency, and skin-friendly properties during use, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a microemulsified plant soap containing moringa seed active ingredients and its preparation method.

[0007] The first aspect of the present invention provides a microemulsified plant soap containing moringa seed active ingredients, wherein the plant soap comprises, by weight percentage, 40-70% soap base, 8-18% moringa pod oil, 0.5-3.0% moringa seed protein extract, 4-10% non-soap-based surfactant system, 5-15% polyol and the balance being water.

[0008] The soap base is obtained by saponification of at least two of the oils selected from coconut oil, palm kernel oil, palm oil and olive oil, and the mass fraction of unsaponified oil in the soap base is 5-12%.

[0009] The moringa pod oil is a vegetable oil extracted from a mixture of moringa pods and moringa seeds in a mass ratio of 1 to 3:1.

[0010] Moringa seed protein extract is a water-soluble protein obtained from defatted, ungerminated moringa seeds, with a protein mass fraction of 60-90%, and a number-average molecular weight of 0.5-5 kDa as determined by gel permeation chromatography in an aqueous solution at pH 7.0.

[0011] The non-soap-based surfactant system consists of C8-C14 alkyl polysaccharides with an average degree of polymerization of 1.3-1.6, cocamidopropyl betaine, and sucrose fatty acid esters and / or polyglycerol fatty acid esters with an HLB value of 12-16, in a mass ratio of (1.5-2.5):(0.8-1.2):(0.5-1.0).

[0012] Among them, after the plant soap is mixed with deionized water at 25℃ at a mass ratio of 1:10, the transmittance at a wavelength of 600nm is not less than 80%, and the volume average particle size of the oil droplets in the resulting dispersion system is 15-60nm as measured by dynamic light scattering, and the polydispersity index is not higher than 0.30.

[0013] The free alkali content of plant soap, calculated as NaOH, is no higher than 0.03%, and the pH value at 25℃ is 6.8 to 7.8.

[0014] By employing the above technical solution, solid soap can form an oil phase distribution and interfacial framework structure that can be rapidly reconstructed in water even before dilution. This structure is determined by the oil composition, interfacial intermolecular forces, and the proportion of residual oil phase in the soap base, ensuring that the oil phase inside the soap does not aggregate in lumps but remains in a finely dispersed state that facilitates secondary interfacial reconstruction. It is this reconstructibility that allows the soap to rapidly recombine into oil droplet structures with particle sizes in the range of 15–60 nm after contact with water, rather than relying on subsequent mechanical dispersion or prolonged stirring.

[0015] This invention utilizes Moringa pod oil, extracted from a mixture of Moringa pods and seeds. The high oleic acid content of Moringa pod oil provides good fluidity and suitable interfacial tortuosity at room temperature, which is beneficial for forming small, uniformly shaped oil droplets in the presence of surfactants. When the total unsaponified oil content in the soap base is controlled at 5–12%, Moringa pod oil, as the main unsaponified oil phase, participates in the construction of the microemulsion core. This provides a single-component oil phase core with a suitable volume fraction for the microemulsion structure without compromising the formability of the solid soap. This facilitates the formation of microemulsion droplets with narrow particle size distribution and high stability, avoiding phase separation or turbidity caused by mixing different oils.

[0016] This invention introduces a moringa seed protein extract obtained from defatted, ungerminated moringa seeds. This extract contains 60-90% protein by mass and a number-average molecular weight between 0.5 and 5 kDa. These small peptides possess both hydrophilic and hydrophobic amino acid residues, allowing them to co-adsorb with non-soap-based surfactants at the microemulsion oil droplet interface, forming a protective interfacial layer. Within this interfacial layer, the small peptides and surfactants form a synergistic adsorption state through weak interactions such as hydrophobic interactions and hydrogen bonds, thereby enhancing the density and flexibility of the oil droplet interfacial film and inhibiting oil droplet aggregation. Furthermore, the small peptides and water-soluble vitamins are immobilized in the interfacial layer structure, effectively preventing direct contact with residual alkaline sites of soap, reducing activity loss due to alkaline hydrolysis and metal-catalyzed oxidation. Since the selected moringa seed protein extract is completely soluble under neutral pH conditions and possesses a certain UV absorption capacity, it provides both physical stability for the oil droplet interface and serves as an effective optical marker for evaluating activity retention.

[0017] This invention employs a non-soap-based surfactant system composed of alkyl polysaccharide, cocamidopropyl betaine, and sucrose fatty acid esters and / or polyglycerol fatty acid esters, with precisely defined mass ratios of the three components. The alkyl polysaccharide is selected from those with a carbon chain length of C8–C14 and an average degree of polymerization of 1.3–1.6. This structure gives the alkyl polysaccharide a high HLB value and good compatibility with transparent systems, enabling the formation of a stable and uniform interfacial framework. Cocamidopropyl betaine, as an amphoteric surfactant, inserts into the alkyl polysaccharide interfacial film, significantly reducing the overall rigidity of the interface, facilitating smoother oil droplet formation, and providing an electrically neutral interface under near-neutral pH conditions, reducing the adverse effects of soap anions on the microemulsion structure. Sucrose esters or polyglycerol esters with HLB values ​​in the range of 12–16 can embed themselves in the gaps between the alkyl polysaccharide and betaine interfacial structures, enhancing the density and hydrogen bond network of the interfacial layer through their polyhydroxyl structures, thereby obtaining a more stable interfacial layer structure that allows the oil droplets to remain uniformly dispersed after dilution.

[0018] The present invention further specifies that when soap and water are mixed at a ratio of 1:10, microemulsion droplets with a volume average particle size of 15-60 nm and a polydispersity index of no more than 0.30 can be spontaneously formed. At the same time, the transmittance of the dispersion at a wavelength of 600 nm is no less than 80%, ensuring that a rapidly reconstructable interfacial network exists inside the solid soap. This ensures that the dispersion state of the active ingredients in the soap remains consistent during use, making the release behavior of Moringa pod oil and small molecule peptides in the interfacial layer more controllable.

[0019] This invention controls the unsaponified oil mass fraction to 5-12% and strictly limits the free alkali content to no more than 0.03% (based on NaOH), thus maintaining the soap base in a balanced state of moderate saponification and low free alkali. This prevents residual free alkali from damaging the microemulsion interface layer, promoting peptide chain breakage, or causing oxidation of active substances. In interfacial dispersion systems, even slight alkalinity weakens the hydrogen bond network, making the interface layer loose, resulting in increased oil droplet size or decreased transparency. Furthermore, protein peptides are prone to deamidation in strongly alkaline environments, reducing interfacial adsorption capacity; while slight acidity promotes the hydrolysis of glycerol ester surfactants, affecting interfacial structural stability.

[0020] Preferably, the moringa pod oil contains 40-55% linoleic acid, 4-10% linolenic acid, 0.02-0.3% docosahexaenoic acid, and a total polyunsaturated fatty acid content of not less than 65%. The peroxide value of the moringa pod oil is not higher than 5 mmol / kg, and the total content of volatile sulfur-containing small molecules, calculated as carbon disulfide, is not higher than 5 mg / kg.

[0021] By limiting the mass fraction of linoleic acid in Moringa pod oil to 40–55%, linolenic acid to 4–10%, and docosahexaenoic acid to 0.02–0.3%, the proportion of polyunsaturated fatty acids in the oil reaches no less than 65%. This allows the unsaponified oil phase to form a more flexible interfacial bending property in the solid soap system, making it easier for oil droplets to recombine into a fine-sized, uniformly shaped dispersion during dilution. Under the combined action of a non-soap-based surfactant system and small molecule peptides, this highly unsaturated oil phase can form a stable synergistic arrangement with the interfacial film, maintaining high fluidity and adsorption balance at the oil droplet interface, thereby improving the transparency and uniformity of the microemulsion structure.

[0022] Under the above fatty acid distribution, the appropriate ratio of linoleic acid to linolenic acid enables the alkoxy segments in the interfacial layer to form strong hydrophobic intercalation with surfactants and small molecule peptides, thereby inhibiting the aggregation tendency of oil droplets during the dilution process. The trace presence of docosahexaenoic acid can further enhance the flexibility of the interfacial film, making the interfacial reconstruction process more stable and conducive to maintaining the fine state of oil droplets in the low-temperature cold soap making system.

[0023] By limiting the peroxide value to no more than 5 mmol / kg, the initial oxidative load of oils in the saponification environment and storage stage can be significantly reduced, so that surfactants and small molecule peptides in the interfacial structure are protected from damage by peroxides and free radicals, thereby improving the continuous transparency of the microemulsion structure and avoiding turbidity and yellowing after dilution.

[0024] In addition, limiting the total content of volatile sulfur-containing small molecules (calculated as carbon disulfide) to no more than 5 mg / kg can effectively reduce the interference of easily migratable volatile components in oils on the soap's odor, interfacial stability, and protein peptide structure, and avoid volatile sulfur compounds causing surface film rupture or local phase separation at the microemulsion interface, thereby further ensuring the stability of the soap's color, transparency, and odor, and improving the final product's appearance, odor, and skin suitability.

[0025] Preferably, the number-average molecular weight polypeptide fragments in the Moringa seed protein extract account for 70-95% of the total polypeptide by mass, and the hydrophobic amino acid residues account for 35-55% of the total amino acid residue molar fraction.

[0026] Preferably, the Moringa seed protein extract is prepared by the following steps:

[0027] (1) Extract defatted Moringa seed powder in an aqueous solution with pH 8.0-9.5 and 25-35℃ at a powder-to-water mass ratio of 1:(10-20) for 30-120 minutes, and centrifuge to remove insoluble matter;

[0028] (2) Adjust the supernatant after centrifugation to pH 4.2-4.8 to precipitate the protein, then dissolve it in an aqueous solution with pH 7.0-8.0, and enzymatically hydrolyze it for 30-180 minutes at 40-55℃ using 1000-5000 U / g of protein.

[0029] (3) The enzymatically hydrolyzed solution is sequentially separated by ultrafiltration membrane with a molecular weight cutoff of 10 kDa, ultrafiltration membrane with a molecular weight cutoff of 3 kDa and nanofiltration membrane with a molecular weight cutoff of 0.5 to 1 kDa. The obtained fractions are spray-dried or freeze-dried to obtain the Moringa seed protein extract.

[0030] By employing the above-mentioned technical solution, the obtained peptide components can exhibit stable interfacial adsorption characteristics. These small-molecule peptides within this molecular weight range possess high interfacial migration rates and strong interfacial binding capabilities, enabling them to form a thin and uniform adsorption layer structure at the oil-water interface. They do not form gel networks in the aqueous phase and are not prone to precipitation in soap-based systems. At the microemulsion oil droplet interface formed after dilution of the solid soap system, these small-molecule peptides can co-arrange with alkyl polyglycosides, betaine, and sucrose esters / polyglycerol esters, resulting in a higher density and flexibility of the interfacial layer and reducing the tendency for oil droplet aggregation.

[0031] If the peptide molecular weight is too large, with long peptide chains and an abundance of hydrophilic segments, it tends to form weak gels or associated structures in the aqueous phase, reducing its ability to migrate to the oil droplet interface. After soap dilution, these large peptide molecules cannot effectively participate in interfacial adsorption, leading to uneven interfacial layer thickness or decreased transparency of the microemulsion system due to peptide chains hindering oil droplet recombination. Conversely, if the molecular weight is too small, the peptide molecules are too short and more easily dissolve completely in the aqueous phase, resulting in insufficient interfacial residence time. This prevents the formation of a stable protective layer at the oil droplet interface, making the interface dependent on surfactant support alone. Consequently, during dilution or storage, oil droplets tend to enlarge and transparency decreases.

[0032] Secondly, the proportion of hydrophobic residues allows peptide molecules to effectively insert into the oil-water interface without causing excessive hydrophobicity that would lead to aggregation and sedimentation within the soap body. This makes it easier to form a mixed interfacial layer with alkyl polysaccharides and sucrose esters. This interfacial structure provides multi-point hydrogen bonds and hydrophobic interactions, increasing the density of the oil droplet interfacial film and enhancing the dimensional stability of the oil droplets during long-term storage.

[0033] Preferably, the moringa seed protein extract, after being prepared in an aqueous solution at pH 7.0 at a mass concentration of 1.0 mg / mL, is completely dissolved after standing at 25°C for 30 min without producing any visible precipitate, and the specific absorbance of the solution at a wavelength of 212 nm is 0.5 to 2.0.

[0034] By adopting the above technical solution, it can be ensured that the peptides can migrate smoothly to the microemulsion droplet interface during the soap system dilution process. If small molecule peptides cannot be completely dissolved under neutral conditions, they will form particles or flocculent precipitates that cannot enter the interface after the solid soap comes into contact with water, making it difficult for peptides to participate in the construction of the interface layer, thereby affecting the formation quality and transparency of the microemulsion droplets.

[0035] The specific absorbance of this solution at 212 nm was limited to 0.5–2.0, which characterizes the effective content of aromatic amino acid residues in Moringa seed extract. Aromatic residues such as tryptophan, tyrosine, and phenylalanine possess conjugated electronic structures, providing primary free radical quenching capabilities at the oil-water interface. This allows them to preferentially capture free radicals or peroxide fragments generated during auto-oxidation at the oil droplet interface. Due to the presence of metal ions and oxygen in the solid soap system, even with a low concentration of diunsaturated fatty acids in the oil phase, oxidation reactions still occur slowly. The aromatic residues at the interface act as the first antioxidant buffer, reducing the oxidation rate of core fatty acids, interfacial sucrose esters, and the small peptides themselves. A specific absorbance within this range indicates that the aromatic residue content in the peptide component is neither too low, resulting in insufficient interfacial antioxidant capacity, nor too high, leading to excessive overall hydrophobicity and easy precipitation.

[0036] Preferably, the mass ratio of Moringa pod oil to Moringa seed protein extract is (15-35):1.

[0037] By adopting the above technical solution, it can be ensured that during the formation and stabilization of microemulsion oil droplets, each unit mass of small molecule peptide serves an appropriate amount of oil core volume, thereby forming a protective layer structure of suitable thickness and continuous arrangement at the oil droplet interface. The interface layer constructed in this proportion can completely cover the oil droplet surface, keeping the oil droplets of uniform size during dilution and oscillation, without causing enhanced light scattering due to excessively thick interface layer, which would lead to turbidity or increased viscosity in the system.

[0038] Preferably, the mass fraction of C8-C10 alkyl polysaccharides in the alkyl polysaccharides is 40-80%, and the mass fraction of C12-C14 alkyl polysaccharides is 20-60%.

[0039] Another aspect of the present invention provides a method for preparing the above-mentioned microemulsion plant soap containing moringa seed active ingredients, comprising the following steps:

[0040] (1) Soap base preparation: At least two of the following oils, coconut oil, palm kernel oil, palm oil and olive oil, are stirred evenly at 20-30℃ in proportion; prepare sodium hydroxide and / or potassium hydroxide aqueous solution, so that the temperature of the alkali solution does not exceed 30℃, and control the equivalent ratio of alkali to saponifiable fatty acids to be 0.88-0.96:1. Add the alkali solution slowly to the mixed oil at 20-35℃, maintain a shear rate of 300-800 r / min and saponify for 30-90 min to obtain a saponified slurry with suitable fluidity; let the saponified slurry stand at 20-30℃ for 24-72 h to stabilize the mass fraction of unsaponifiable oil at 5-12% to obtain cold-process soap base;

[0041] (2) Preparation of Moringa Seed Active Pre-emulsion: At 20-30℃, Moringa seed protein extract was dissolved in a mixed solvent composed of polyol and water to obtain a protein solution, and the pH was adjusted to 6.8-7.5; under stirring conditions, C8-C14 alkyl polysaccharide and cocamidopropyl betaine in a non-soap-based surfactant system were added in sequence, and the protein solution was fully mixed with the above surfactants. Moringa seed oil was slowly added at 25-35℃ and high-speed shear emulsification was carried out for 5-20 min to obtain Moringa seed active pre-emulsion with an average oil droplet volume diameter of no more than 100 nm.

[0042] (3) Microemulsion plant soap molding: At 25-35℃, the soap base obtained in step (1) is added to a mixing tank. The active pre-emulsion of Moringa pods obtained in step (2) is added in batches at a shear rate of 800-2500 r / min. At the same time, the remaining sucrose fatty acid ester and / or polyglycerol fatty acid ester in the non-soap-based surfactant system are added. After mixing at the above shear rate for 5-20 min, the shear rate is adjusted to 200-600 r / min and mixing is continued for 5-20 min to form a uniform concentrated microemulsion paste. Then, an organic acid aqueous solution is added at a temperature not higher than 30℃ to adjust the pH of the system to 6.8-7.8. The mixture is allowed to stand for 0.5-4 h to defoam. The material is then injected into a mold and cured at 20-30℃ for 24-72 h to obtain a microemulsion plant soap containing the active ingredients of Moringa pods.

[0043] By employing a cold process soaping method in step (1) at a temperature range of 20–35°C, the saponification and maturation of oils are completed under low-temperature conditions, effectively avoiding the oxidation reaction of unsaponified oils and the thermal degradation of protein-based active substances under high-temperature conditions. The alkali-to-saponifiable fatty acid equivalent ratio is controlled at 0.88–0.96:1, ensuring a suitable content of unsaponified oils in the saponification reaction. This maintains the required solid network structure of the soap while providing appropriate fluidity for the unsaponified oil phase, facilitating the subsequent formation of a stable microemulsion composite structure with the active pre-emulsion. The saponified slurry is matured at a lower temperature for 24–72 hours, gradually densifying the internal structure of the soap base and maintaining a controllable lipophilic-hydrophilic balance, providing a stable skeletal environment for the subsequent integration of active ingredients.

[0044] Step (2) involves pre-dissolving the Moringa seed protein extract and adjusting it to a weakly neutral pH of 6.8–7.5 to maintain the high conformational stability of the small peptides and prevent deactivation or breakage under alkaline conditions. The protein solution forms a composite interface layer with C8–C14 alkyl polysaccharides and cocamidopropyl betaine, reducing the interfacial tension at the oil-water interface. This allows the Moringa pod oil to be rapidly refined into droplets with a volume average particle size of no more than 100 nm during high-speed shearing, thus forming an active pre-emulsion with high transparency and dispersion stability. This process achieves the directional binding of oils and protein peptides, enabling the active components to exist in a stable, intercalated structure within the soap body, thereby improving its storage stability.

[0045] In step (3), the active pre-emulsion is added to the soap base in batches while maintaining an initial high shear rate of 800–2500 r / min. This allows the microemulsion structure to fully penetrate the soap base network, enabling the oil droplets to achieve uniform integration within the soap base system. Subsequently, the shear rate is reduced to 200–600 r / min to further stabilize the system and prevent oil droplet rearrangement or film rupture caused by high shear. The sucrose fatty acid esters and / or polyglycerol fatty acid esters added during the process can form a second interfacial film on the surface of the oil droplets, which, together with the protein-alkyl polysaccharide complex layer, constructs a stable multilayer interfacial structure, making it less likely for the oil droplets to aggregate and separate from the phase under storage and usage conditions. By adjusting the pH of the system to 6.8–7.8 using an organic acid aqueous solution at a temperature not exceeding 30°C, the final soap body is kept in a weakly acidic to neutral range, improving its gentleness on the skin and avoiding protein-peptide structure damage or oil phase oxidation caused by high pH conditions.

[0046] Preferably, after the high-speed shear emulsification in step (2) is completed, the moringa seed active pre-emulsion is adjusted to 25-35°C and slowly stirred for 10-60 minutes under the condition of shear rate of 200-800 r / min before step (3).

[0047] After high-speed shear emulsification, the temperature of the Moringa seed active pre-emulsion is adjusted to 25–35°C, and it is slowly stirred for 10–60 min at a lower shear rate of 200–800 r / min. This allows the newly formed nanodroplets to undergo interfacial rearrangement and internal stress relaxation in a gentle flow field, which is beneficial for the formation of a denser and more uniform composite interfacial film of Moringa seed small molecule peptides, alkyl polysaccharides, and cocamidopropyl betaine on the droplet surface. Compared with proceeding to the next step immediately after emulsification, adding this structural stabilization stage can significantly reduce the risk of droplet aggregation and demulsification during subsequent mixing with soap base, making the pre-emulsion more stable in terms of particle size and distribution.

[0048] This slow-stirring aging step also makes the pre-emulsion more resistant to temperature fluctuations and shear disturbances, reducing the likelihood of localized flocculation or turbidity during subsequent high-shear blending of soap bases and pH adjustment. This helps maintain the transparent appearance and low polydispersity index of the final microemulsion plant soap. Simultaneously, this step reduces the tendency for free proteins or hydrophobic peptides to aggregate in the system, minimizing interference with the soap base network structure. This makes the finished product less prone to stratification, turbidity rings, and oil separation during long-term storage, thereby improving the product's appearance stability and consistency in feel.

[0049] Preferably, in step (3), the microemulsified plant soap is formed by segmented pH adjustment and degassing under reduced pressure:

[0050] A mixed aqueous solution of citric acid and lactic acid is first added at 25–30°C to adjust the pH of the system to 7.8–8.5. After standing for 20–60 minutes, the mixed aqueous solution is added again to adjust the pH to 6.8–7.8. After pH adjustment, the system is degassed under slight reduced pressure (−0.02–−0.06 MPa) for 5–20 minutes and / or under normal pressure for 0.5–4 hours at a temperature not exceeding 30°C to remove air bubbles. The material is then injected into a mold for curing and shaping.

[0051] By employing the above technical solution, the fatty acid salts in the soap base maintain a high degree of dissociation, while providing a moderate charge density environment for the moringa seed small molecule peptides and non-soap-based surfactants. This allows the components to complete the second interfacial rearrangement and organization process under conditions close to the saponification system. After standing for 20–60 minutes, the pH is further adjusted to 6.8–7.8, allowing the system to transition smoothly from a strongly saponified state to a near-neutral, mild range. Compared to adjusting directly from a strong alkali to neutral in one step, this significantly reduces the abrupt effect of fatty acid salts converting to free fatty acids, and lowers the probability of local precipitation, turbidity, and droplet aggregation.

[0052] Immediately after completing the segmented pH adjustment, vacuum degassing is performed for 5–20 minutes at -0.06 to -0.09 MPa. This removes microbubbles introduced by high-speed shearing and mixing without damaging the nanoemulsion structure, reducing light scattering points and potential oxidation interface sites. This results in higher optical transparency and better color uniformity in the diluted product. The vacuum degassing, combined with the aforementioned segmented pH adjustment, stabilizes the microemulsion system at both the gas-liquid and oil-water interfaces. This inhibits structural collapse caused by bubbles and avoids damage to the interfacial film between Moringa seed protein extract and fatty acid salts caused by localized pH abrupt changes, thereby further improving the product's clarity, mechanical strength, and sensory consistency during storage.

[0053] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in the following aspects:

[0054] This invention creates a suitable and stable unsaponifiable oil structure in the soap base, enabling the solid soap to possess a reconstructable micro-oil phase framework after molding. This oil phase is derived from specially refined and compositionally controlled Moringa pod oil, whose hydrocarbon chain flexibility and interfacial affinity are superior to traditional vegetable oils. It maintains stable dispersion within the soap body for extended periods without forming continuous oil zones or visible oil droplets. Upon contact with water, the oil phase in the soap body rapidly reorganizes into a fine and uniform microemulsion structure, resulting in higher transparency and better optical uniformity in the finished product. Simultaneously, it significantly reduces the problems of turbidity, oil separation, and incomplete emulsification commonly found in traditional plant-based soaps.

[0055] Secondly, this invention utilizes small molecule peptides from Moringa seeds with interfacial activity to construct a composite interfacial layer together with alkyl polysaccharides, cocamidopropyl betaine, and sucrose fatty acid esters or polyglycerol fatty acid esters. This interfacial structure possesses high flexibility and stability, continuously inhibiting oil droplet aggregation and phase separation within the soap body and during diluted use, and effectively reducing oxidation reactions at the interface, ensuring the microemulsion structure remains transparent, delicate, and stable during formation and use. Simultaneously, the small molecule peptides maintain conformational integrity in weakly acidic to neutral environments, are not easily deactivated by the soap base environment, and allow the active ingredients to be released in a stable state during use.

[0056] Furthermore, this invention optimizes the composition and ratio of the non-soap-based surfactant system, ensuring a coordinated interfacial framework in both the solid soap and dilution stages. This system not only accelerates microemulsion formation but also stabilizes the oil droplet interface, thereby improving the clarity, smoothness, and skin feel of the transparent soap. Without relying on traditional anionic systems, this invention achieves a balance between cleaning power, gentleness, and transparency.

[0057] Furthermore, this invention comprehensively limits the solubility, hydrophobic residue content, and ratio of the protein extract to the oil phase, ensuring that the small molecule peptides maintain good interfacial activity during storage, preventing sedimentation or self-aggregation, and avoiding turbidity in the soap. Aromatic residues in the protein can inhibit free radical chain reactions at the interfacial layer, thereby significantly delaying the oxidation of vegetable oils and surfactants, allowing the soap to maintain stable color, transparency, and odor throughout its shelf life.

[0058] The preparation process of this invention optimizes the interfacial layer from formation to soap curing through steps such as high-speed shear nucleation of the pre-emulsion, low-shear aging, soap base blending, segmented pH adjustment, and low-temperature defoaming. This process effectively avoids demulsification, flocculation, and localized structural collapse caused by traditional direct mixing, allowing the soap to form a stable composite interfacial network after curing. During use, this structure quickly reverts to a transparent microemulsion system, maintaining excellent skin feel, gentleness, and retention of active ingredients. Detailed Implementation

[0059] The present invention will now be described in detail with reference to the embodiments.

[0060] Preparation Example 1

[0061] This preparation example discloses a method for preparing Moringa seed protein extract, including the following steps:

[0062] (1) Alkali extraction

[0063] Weigh 1.0 kg of defatted Moringa seed powder (using SKU: RA360 from Medikonda Nutrients, which is Moringa seed cake obtained by pressing and degreasing ungerminated seeds, further pulverized to approximately 60-80 mesh brown powder), add 15.0 kg of deionized water, stir well, and adjust the pH of the system to 9.0 with 2 mol / L sodium hydroxide solution. Extract for 60 min at 400 rpm in a 30℃ water bath. After extraction, centrifuge the slurry at 8000 rpm and 4℃ for 20 min, discard the precipitate, and collect the supernatant for later use.

[0064] (2) Enzymatic hydrolysis

[0065] Add 2 mol / L hydrochloric acid solution to the supernatant obtained in step (1) to adjust the pH to 4.5, and let it stand at 25℃ for 30 min to promote complete protein precipitation. Then centrifuge at 8000 r / min and 4℃ for 15 min, discard the supernatant and collect the protein precipitate.

[0066] The obtained protein precipitate was resuspended in deionized water, and the pH was adjusted to 7.5 with 1 mol / L sodium hydroxide solution to achieve a protein concentration of 50 g / L. A complex neutral protease (Alcalase® 2.4L FG from Novozymes, with an enzyme activity ≥2.4 AU / g) was added at 50°C at a dosage of 3000 U / g based on protein mass. The pH was maintained at 7.5, and the mixture was stirred at 300 rpm for 90 min. After hydrolysis, the system was heated to 90°C and incubated for 10 min to inactivate the protease. The system was then cooled to 30°C for later use.

[0067] (3) Membrane grading and drying

[0068] The enzymatic hydrolysate obtained in step (2) is first fed into an ultrafiltration membrane module with a molecular weight cutoff of 10 kDa. Ultrafiltration is performed at 0.20 MPa and 25°C. The 10 kDa ultrafiltration membrane permeate is collected, and the 10 kDa ultrafiltration membrane retentate is discarded.

[0069] The 10kDa permeate was fed into an ultrafiltration membrane module with a molecular weight cutoff of 3kDa and ultrafiltration was performed at 0.18MPa and 25°C. The 3kDa ultrafiltration membrane permeate was collected and the 3kDa ultrafiltration membrane retentate was discarded.

[0070] The 3kDa permeate was fed into a nanofiltration membrane module with a molecular weight cutoff of 0.8kDa, and nanofiltration was performed at 0.25MPa and 25℃. The 0.8kDa nanofiltration membrane retentate was collected, and the 0.8kDa nanofiltration membrane permeate was discarded.

[0071] The obtained 0.8 kDa nanofiltration membrane retentate was concentrated under vacuum at 50°C to a solids content of approximately 20%, and then powdered using a spray drying process: inlet air temperature 170°C, outlet air temperature 85°C, and feed flow rate 5 mL / min, yielding a light yellow powdered Moringa seed protein extract. The obtained powder was sealed in an aluminum foil bag and stored at 4°C for later use.

[0072] The performance of the Moringa seed protein extract prepared above was tested, and the methods and results are as follows:

[0073] 1. Protein mass fraction detection:

[0074] Approximately 0.20 g of sample was taken, and the total nitrogen content was determined using the Kjeldahl method. The determination method followed the standard food protein determination method (with sulfuric acid digestion, boric acid absorption, and hydrochloric acid titration as the basic steps). The digestion temperature was 420℃, and the digestion time was 90 min. The protein content was calculated using a nitrogen-protein conversion factor of 6.25.

[0075] The protein content of the Moringa seed protein extract was measured to be 78.5 wt%.

[0076] 2. Detection of number-average molecular weight and proportion of 0.5–3 kDa fragments (gel permeation chromatography)

[0077] Weigh 10.0 mg of Moringa seed protein extract, dissolve it in 10.0 mL of 20 mmol / L phosphate buffer (PBS) at pH 7.0, filter it through a 0.22 μm microporous membrane, and then perform gel permeation chromatography (GPC) analysis.

[0078] A molecular weight-retention time calibration curve was established using a series of peptide standards with known molecular weights (e.g., 0.5, 1, 2, 3, 5 kDa). The number-average molecular weight Mn of the sample was calculated based on the calibration curve. The peak area corresponding to the molecular weight range of 0.5–3 kDa in the chromatogram was segmented and integrated to calculate the percentage of the peptide fragment in this range to the total peak area.

[0079] The measured result is: the number-average molecular weight Mn is 1.8 kDa;

[0080] The peak area of ​​peptide fragments in the molecular weight range of 0.5–3 kDa accounted for 86.0 wt% of the total peak area (calculated based on the approximate mass fraction of peak area).

[0081] 3. Detection of amino acid composition and molar fraction of hydrophobic amino acid residues

[0082] Take approximately 5.0 mg of sample, add 2.0 mL of 6 mol / L hydrochloric acid, seal under nitrogen purging, and hydrolyze at 110 °C for 24 h. After hydrolysis, cool to room temperature, remove hydrochloric acid under reduced pressure until nearly dry, and dilute the residue to 5.0 mL with citric acid buffer solution (pH 2.2) for analysis using an automated amino acid analyzer.

[0083] Amino acid analysis was performed using conventional ion-exchange chromatography followed by ninhydrin colorimetric method, and the molar fraction of each amino acid residue was calculated. Alanine (Ala), valine (Val), isoleucine (Ile), leucine (Leu), phenylalanine (Phe), proline (Pro), methionine (Met), and tryptophan (Trp) were defined as hydrophobic amino acid residues, and the molar percentage of the sum of these hydrophobic amino acid residues relative to the total amino acid residues was calculated.

[0084] The molar fraction of hydrophobic amino acid residues in the Moringa seed protein extract was measured to be 41.0 mol.

[0085] Preparation Example 2: Preparation of Moringa pod oil

[0086] This preparation example discloses a method for preparing Moringa pod oil, including the following steps:

[0087] (1) Raw material pretreatment: Dried, ungerminated Moringa pods and seeds were selected as raw materials, with a mass ratio of 2:1. The overall moisture content of the mixture of pods and seeds was 7.5%, and the impurity content was 0.4%. After mixing Moringa pods and seeds evenly at a mass ratio of 2:1, large particles of impurities were removed by sieving through a 5mm mesh screen, and light impurities were removed by air separation. The pretreated mixture was placed in a 45℃ hot air circulating oven and dried for 4 hours to reduce the moisture content of the mixture to 6.0%. After drying, it was cooled to 25℃ for later use.

[0088] (2) Cold pressing for oil extraction: The pretreated moringa pods and moringa seeds mixture was added to a screw oil press and cold pressed at a feed rate of 70 kg / h. The pressing chamber temperature was controlled at 50℃ and the oil outlet temperature at 55℃. The crude oil was collected and filtered through an 80-mesh stainless steel filter to obtain 22.0 kg of crude moringa pod oil and 7.0 kg of oil residue.

[0089] (3) Settling and degumming: The moringa pod oil was injected into a settling tank with a bottom valve and settling at 25°C for 24 hours. The lower sediment phase was discharged through the drain valve, and the upper clear oil was filtered through a 100-mesh filter cloth to obtain 20.4 kg of pre-degummed moringa pod oil.

[0090] (4) Hydration and degumming: Deionized water at 70°C was slowly added to the pre-degummed Moringa pod oil at a rate of 2.0% of the oil mass. The mixture was stirred at 200 r / min for 30 min at 55°C. After stirring, the system was allowed to stand for 4 h. The lower layer containing gum was released, and the upper oil phase was filtered through filter paper to obtain 19.2 kg of degummed Moringa pod oil.

[0091] (5) Alkali refining and neutralization: Prepare a sodium hydroxide aqueous solution with a mass fraction of 0.10 mol / L. Heat the degummed moringa pod oil to 45°C, and add the above sodium hydroxide solution at a rate of 6.0% of the oil mass in one go while stirring at 150 r / min. Maintain the temperature at 45°C and stir for 20 min to complete the neutralization of free fatty acids. After standing for 2 h, release the lower layer of soapstock. Wash the upper clear oil twice with deionized water at 70°C, with the amount of water used each time being 15.0% of the oil mass. After each wash, let it stand at 45°C for 1 h, and release the lower aqueous phase to obtain 18.0 kg of neutralized and washed moringa pod oil.

[0092] (6) Vacuum dehydration and deodorization: The neutralized and washed Moringa pod oil was placed in a refining kettle equipped with a vacuum system. The temperature was raised to 90°C under a vacuum of -0.085 MPa and maintained at 90°C and -0.085 MPa for 40 min to dehydrate the oil until the moisture content dropped below 0.10%. Subsequently, the temperature was raised to 185°C under the same vacuum, and 0.3 kg / h of superheated steam was introduced from the bottom of the kettle for deodorization and removal of volatile components for 70 min. After the treatment, the steam was stopped, and the temperature was lowered to 60°C under stirring at -0.085 MPa. Powdered activated carbon equivalent to 0.05% of the oil mass was added, and the temperature was maintained at 60°C for stirring for 30 min. The activated carbon was then removed by plate and frame filtration. The temperature was then lowered to 50°C under vacuum, nitrogen was introduced to atmospheric pressure, and finally the temperature was lowered to 25°C to obtain 16.9 kg of refined Moringa pod oil.

[0093] The refined moringa seed oil obtained was tested using the following methods:

[0094] 1. Acid value: According to GB / T5530-2005, the acid value was determined by potassium hydroxide titration, and the result was 0.29 mg KOH / g.

[0095] 2. Peroxide value: According to GB / T5538-2005 (expressed as milliequivalents of active oxygen), the peroxide value was measured to be 4.1 mmol / kg.

[0096] 3. Fatty acid composition: Oil samples were subjected to methyl esterification according to GB / T17376-2008, and the fatty acid methyl ester composition was determined by gas chromatography. The mass fraction of each fatty acid was calculated using the peak area normalization method. The mass fractions of the main fatty acids are shown in Table 1 below.

[0097] Table 1

[0098] Types of fatty acids carbon chain form Mass fraction (wt%) Palmitic acid C16:0 5.0 stearic acid C18:0 3.6 Oleic acid C18:1 31.5 Linoleic acid C18:2 47.9 Alpha-linolenic acid C18:3 5.9 Docosahexaenoic acid (DHA) C22:6 0.08 Arachidonic acid and other trace fatty acids C20:0 etc. 6.0

[0099] 4. Volatile sulfur-containing small molecules were detected in both the raw Moringa pod oil before hydration and degumming and the refined Moringa pod oil after step (6). The headspace sampling-gas chromatography method was used for detection, with carbon disulfide as the quantitative indicator.

[0100] Test results show that:

[0101] The carbon disulfide content in the oil from the pods of Moringa before hydration and degumming was 28.4 mg / kg;

[0102] The carbon disulfide content in refined Moringa pod oil after vacuum dehydration, steam deodorization, and activated carbon treatment was reduced to 1.5 mg / kg.

[0103] Example 1

[0104] This embodiment discloses a microemulsified plant soap containing moringa seed active ingredients and its preparation method. The formula of the microemulsified plant soap containing moringa seed active ingredients is as follows:

[0105] Soap base: 56.0%, Moringa seed oil: 12.0% (Moringa pod oil obtained in Preparation Example 2), Moringa seed protein extract: 0.8% (Moringa seed protein extract prepared in Preparation Example 1), non-soap-based surfactant system: 5.7% (C8-C14 alkyl polysaccharide glycoside: 3.0%, cocamidopropyl betaine: 1.5%, sucrose fatty acid ester (HLB 14): 1.2%), polyol: 10.0% (glycerol: 6.0%, propylene glycol: 3.0%, sorbitol: 1.0%), deionized water: 15.5%, wherein:

[0106] The soap base contains 8.5% unsaponifiable oil by mass, of which Moringa seed oil accounts for 90% of the total unsaponifiable oil.

[0107] C8-C14 alkyl polysaccharides were selected from APG 1214 from Dalian Handong Chemical Co., Ltd.

[0108] Cocamidopropyl betaine was selected from CAPB-35 of Shanghai Boyun New Materials Co., Ltd.

[0109] The sucrose fatty acid ester used is model S-1570 from Mitsubishi Chemical Corporation's RYOTO™ Sugar Ester series of fatty acid sucrose esters.

[0110] The steps for preparing plant-based soap are as follows:

[0111] (1) Cold process soap base preparation: Add 30 parts coconut oil, 20 parts palm kernel oil, 30 parts palm oil and 20 parts olive oil to the mixing tank, mix and stir at 25°C for 15 minutes. Pass 20°C cooling water into the jacket to keep the system temperature at 25°C.

[0112] Prepare a 30% sodium hydroxide aqueous solution and cool it to 20°C. Calculate the dosage based on an alkali to saponifiable fatty acid equivalent ratio of 0.92:1. Gradually add the alkali solution to the oil phase over 20 minutes, maintaining a stirring speed of 450 rpm. During the alkali addition process, continuously circulate 20°C cooling water to maintain the system temperature at 30°C. After the alkali solution is completely added, stir at 30°C for 50 minutes until the system forms a homogeneous paste with a pH of 11.0, obtaining a saponified slurry. Pour the slurry into a curing tank and let it stand at 25°C for 24 hours to obtain a soap base with an unsaponifiable oil content of 8.5%. Cut the soap base into blocks and store at 25°C for later use.

[0113] (2) Preparation of Moringa pod active pre-emulsion: 6.0 parts of glycerol, 3.0 parts of propylene glycol, and 6.0 parts of deionized water were added to an emulsifying tank and stirred evenly at 25°C. 0.8 parts of Moringa seed protein extract were added to the system and stirred at 28°C for 30 min to dissolve it. The pH of the system was adjusted to 7.2 using sodium citrate solution, and the temperature was maintained at 28°C. 3.0 parts of C8-C14 alkyl polysaccharide and 1.5 parts of cocamidopropyl betaine were added to the system and stirred at 28°C for 20 min. After the refined Moringa pod oil was equilibrated in an environment of 28°C, the above mixed solution was added to an emulsifier. Moringa pod oil was added dropwise over 10 min at 8000 r / min and 30°C, and then emulsified for another 5 min at 8000 r / min and 30°C to obtain a pre-emulsion with a volume average particle size of approximately 45 nm.

[0114] (3) Molding of microemulsified plant soap: Cut the cured soap base into blocks and place them in a planetary mixing tank. Cooling water at 20°C is introduced through the jacket to maintain the system temperature at 28°C. Stir at 2000 r / min for 10 min to plasticize the soap base. At 28°C, the pre-emulsion is added in three portions, stirring at 2000 r / min for 5 min after each addition. Then, 1.2 parts of sucrose fatty acid ester are added, and the mixture is stirred at 28°C and 2000 r / min for 10 min. The stirring speed is reduced to 400 r / min, and mixing continues at 28°C for 15 min to ensure uniformity. Then, the prepared organic acid mixture is slowly added to adjust the pH of the system to 7.4, while maintaining the temperature at 28°C. After stopping stirring, the mixture is allowed to stand at 28°C for 1 h to degas. The paste is poured into soap molds and cured at 25°C for 48 h before demolding to obtain a microemulsified plant soap sample with good transparency.

[0115] Example 2

[0116] The difference between this embodiment and Embodiment 1 is that the moringa pod oil used in this embodiment has a different composition and oxidative stability than that in Embodiment 1 by changing the raw material ratio of pods and moringa seeds and the corresponding oiling parameters.

[0117] Specifically as follows:

[0118] (1) Raw material pretreatment: Dried, ungerminated Moringa pods and seeds were selected as raw materials, with a mass ratio of pods to seeds of 3:1. The overall moisture content of the mixture was 7.5%, and the impurity content was 0.4%. Large particles of impurities were removed by passing the mixed raw materials through a 5mm mesh screen, and light impurities were removed by an air classifier. The pretreated mixture was placed in a 50℃ hot air circulating oven and dried for 6 hours to reduce the moisture content to 5.8%. After drying, it was cooled to 25℃ for later use.

[0119] (2) Cold pressing for oil extraction: The mixture is added to a screw oil press with a feeding speed of 75 kg / h, a pressing chamber temperature of 55℃, and an oil outlet temperature of 60℃. The extracted crude oil is collected and filtered through a 60-mesh filter to obtain moringa pod oil.

[0120] (3) Settling and degumming: The crude oil is injected into a settling tank and left to stand at 25°C for 36 hours. The lower sediment phase is discharged through the bottom valve, and the upper clear oil is filtered through an 80-mesh filter cloth to obtain pre-degummed Moringa pod oil.

[0121] (4) Hydration and degumming: Add 70°C deionized water to the pre-degummed oil at a rate of 1.5% of the oil mass, and stir at 250 r / min for 40 min at 60°C. After stirring, let stand for 6 h, release the lower phase, and filter the upper oil through filter paper to obtain degummed Moringa pod oil.

[0122] (5) Alkali refining and neutralization: Prepare a sodium hydroxide solution with a mass fraction of 0.12 mol / L. Heat the degummed oil to 50°C, and add 5.0% of the alkali solution by mass while stirring at 180 r / min. Maintain the stirring temperature at 50°C for 25 min. After standing for 3 h, release the soap stubble. Wash the upper clear oil three times with 75°C deionized water, each time using 20.0% of the oil mass. After washing, let stand for 1 h to obtain neutralized oil.

[0123] (6) Vacuum dehydration and deodorization: The neutralized oil was placed in a refining kettle and heated to 95°C under a vacuum of -0.090 MPa for 50 min. Then, the temperature was raised to 185°C, and superheated steam at a rate of 0.4 kg / h was introduced from the bottom of the kettle for 80 min of deodorization. After deodorization, the steam supply was stopped, and the mixture was cooled to 60°C under a vacuum of -0.090 MPa. Powdered activated carbon equivalent to 0.05% of the oil mass was added, and the mixture was stirred at 60°C for 30 min. The activated carbon was removed by plate and frame filtration. The mixture was then cooled to 50°C under vacuum, and nitrogen was introduced to atmospheric pressure. The mixture was then cooled to 25°C to obtain refined Moringa pod oil.

[0124] The refined moringa seed oil obtained was tested using the following methods:

[0125] 1. Acid value: According to GB / T 5530-2005, the acid value was determined by potassium hydroxide titration, and the result was 0.41 mg KOH / g.

[0126] 2. Peroxide value: According to GB / T 5538-2005 (expressed as milliequivalents of active oxygen), the peroxide value was measured to be 13.6 mmol / kg.

[0127] 3. Fatty acid composition: Oil samples were subjected to methyl esterification according to GB / T 17376-2008, and the fatty acid methyl ester composition was determined by gas chromatography. The mass fraction of each fatty acid was calculated using the peak area normalization method. The mass fractions of the main fatty acids are shown in Table 2 below.

[0128] Table 2

[0129] Types of fatty acids carbon chain form Mass fraction (wt%) Palmitic acid C16:0 7.2 stearic acid C18:0 4.8 Oleic acid C18:1 54.2 Linoleic acid C18:2 19.4 Alpha-linolenic acid C18:3 3.1 Arachidonic acid and other trace fatty acids C20:0 etc. 11.3

[0130] Example 3

[0131] The difference between this embodiment and Example 1 lies in the preparation steps of the Moringa seed protein extract, specifically:

[0132] In the enzymatic hydrolysis step: the enzyme dosage was reduced to 1200 U / g, the hydrolysis time was shortened to 40 minutes, the hydrolysis temperature was maintained at 45℃, and the protein precipitate after hydrolysis was resuspended in deionized water and adjusted to pH 7.2.

[0133] In the membrane fractionation and drying steps: the membrane molecular weight cutoffs were adjusted to 5 kDa and 1 kDa, and the 5 kDa ultrafiltrate was concentrated as the main product, eliminating the use of the 0.8 kDa nanofiltration membrane. Spray drying was employed to dry the protein powder to an 18% solids content.

[0134] The test results showed that the Moringa seed protein extract in this example had a protein mass fraction of 81.2%. The number average molecular weight (Mn) was 4.6 kDa; the peak area of ​​polypeptide fragments in the molecular weight range of 0.5–3 kDa accounted for 41.3 wt% of the total peak area, and the proportion of fragments in the range of 3–10 kDa was 56.7 wt%. The molar fraction of hydrophobic amino acid residues was 40.5 mol.

[0135] Comparative Example 1

[0136] This comparative example follows the overall formula and process of Example 1, but replaces the Moringa pod oil with an equal amount of sweet almond oil by weight. Apart from this substitution, the types and amounts of other raw materials, as well as the preparation steps, remain the same.

[0137] Sweet almond oil is from the German company IOIOleo GmbH, and the product model is IOIAlmondOil (INCI: Prunus Amygdalus DulcisOil).

[0138] The main components and quality indicators of this oil are as follows: oleic acid 62wt%, linoleic acid 28wt%, linolenic acid <0.5wt%, and peroxide value 5mmol / kg.

[0139] Comparative Example 2

[0140] This comparative example uses all the raw materials and steps of Example 1, except that the Moringa seed protein extract is replaced with the same amount of hydrolyzed wheat protein.

[0141] The hydrolyzed wheat protein used is Hydrolyzed Wheat Protein (model: HWP-01) from Shanghai Herui Biotechnology Co., Ltd., with a molecular weight range of 3 to 10 kDa and a protein content of not less than 95%.

[0142] Comparative Example 3

[0143] The difference between the formulation in Example 1 and the formulation in Example 2 is that the C8-C14 alkyl polysaccharides in the non-soap-based surfactant system are replaced by hexadecyltrimethylammonium bromide in equal amounts.

[0144] Performance testing

[0145] The solid plant soap samples from the examples and comparative examples were mixed with deionized water at a mass ratio of 1:10 at 25°C to form a diluted solution, and then the following tests were performed.

[0146] 1. Oil droplet size and dispersibility test

[0147] Methods: The volume-average particle size and polydispersity index of oil droplets in microemulsion plant soaps were tested using dynamic light scattering (DLS).

[0148] Test conditions: The sample was mixed with deionized water at a mass ratio of 1:10 at 25℃, and the transmittance at a wavelength of 600nm was measured.

[0149] Data calculation: Measurement of the volume average diameter (D) of oil droplets 80 The polydispersity index (PDI) is used to assess its dispersion and uniformity.

[0150] The test results are shown in Table 3 below.

[0151] Table 3

[0152] Examples / Comparative Examples Oil droplet volume average diameter (nm) Polydispersity Index (PDI) Light transmittance (600nm) Example 1 45 0.18 83% Example 2 47 0.19 81% Example 3 52 0.2 80% Comparative Example 1 62 0.28 76% Comparative Example 2 75 0.32 72% Comparative Example 3 95 0.35 68%

[0153] 2. Test for unsaponified oil content in soap base

[0154] Method: The mass fraction of unsaponifiable oils in soap base samples obtained by dehydration under reduced pressure after heating saponification reaction was determined.

[0155] Test conditions: The oil in solid soap was extracted directly using Soxhlet extraction with anhydrous ethanol as the solvent, and the oil mass fraction was measured.

[0156] The test results are shown in Table 4 below.

[0157] Table 4

[0158] Examples / Comparative Examples Unsaponified fat mass fraction (%) Example 1 8.5 Example 2 9 Example 3 8 Comparative Example 1 8.3 Comparative Example 2 7.5 Comparative Example 3 9.2

[0159] 3. pH value and free alkali content test

[0160] Method: pH test: The pH value of the extract was measured using a pH meter.

[0161] Free alkali content test: The free alkali content (calculated as NaOH) is calculated by titration with sodium hydroxide solution.

[0162] The test results are shown in Table 5 below.

[0163] Table 5

[0164] Examples / Comparative Examples pH value Free alkali content (NaOH %) Example 1 7.4 0.02 Example 2 7.5 0.03 Example 3 7.3 0.02 Comparative Example 1 7.8 0.05 Comparative Example 2 7.6 0.06 Comparative Example 3 8.1 0.07

[0165] 4. Transparency and Sensory Evaluation

[0166] Transparency Test: Take a sample of solid plant-based soap, cut it into standard small pieces, add deionized water (mass ratio 1:10), and allow it to dissolve naturally to form an aqueous solution, or accelerate dissolution by slight heating. Use a transmittance meter to test the transmittance of the solution at a wavelength of 600 nm to evaluate the transparency. The higher the transmittance, the better the transparency.

[0167] Calculation formula: transmittance = (I / I0) × 100%, where I is the transmitted light intensity of the sample and I0 is the original light intensity.

[0168] Sensory evaluation:

[0169] Scoring criteria: Sensory evaluation will be conducted by three professional judges. The evaluation items include aroma, color, foam stability, texture, and touch. The scoring range is 1 (poor) to 5 (excellent).

[0170] Aroma: Assess whether the aroma of the solid soap is fresh and natural, and whether there are any unpleasant odors.

[0171] Color: Evaluate the color of the soap to see if it is uniform and without obvious color difference.

[0172] Foam stability: Solid plant-based soap is rubbed under standard conditions (room temperature, appropriate amount of water) to form foam, and the foam generation, persistence and stability are evaluated.

[0173] Texture and feel: Assess whether the soap surface is smooth and whether it is gentle and non-irritating when used.

[0174] The test results are shown in Table 6 below.

[0175] Table 6

[0176] Examples / Comparative Examples Light transmittance (600nm) Aroma (1-5) Colors (1-5) Foam stability (1-5) Texture / Feel (1-5) Example 1 83% 4 5 5 5 Example 2 81% 4 4 4 4 Example 3 80% 4 4 4 4 Comparative Example 1 76% 3 3 3 3 Comparative Example 2 72% 2 2 2 2 Comparative Example 3 68% 2 2 2 2

[0177] 5. Skin mildness test

[0178] Skin irritation testing: Direct contact testing was conducted using human skin models approved by the ethics committee.

[0179] After dissolving the solid plant-based soap in water, apply the standard dosage (0.5g) directly to the surface of the skin model and leave it in contact for 24 hours. After the test, evaluate the appearance changes of the model, including redness, swelling, and skin peeling, using a standard scoring system (0: no irritation, 1: slight irritation, 2: moderate irritation, 3: severe irritation).

[0180] Skin mildness assessment:

[0181] Scoring criteria: The experimental data were scored by three professional dermatologists.

[0182] Rating criteria: 1 point is very harsh, 5 points is very mild.

[0183] Skin allergy test: The plant-based soap was applied to a small area of ​​the volunteer's skin and the reaction was observed within 24 hours (allergy reaction score: 0 for no reaction, 1 for mild redness and swelling, 2 for moderate redness and swelling, and 3 for severe allergic reaction).

[0184] The test results are shown in Table 7 below.

[0185] Table 7

[0186] Examples / Comparative Examples Stimulus rating (0-3) Mildness rating (1-5) Allergic reaction score (0-3) Example 1 0 5 0 Example 2 0 4 0 Example 3 1 3 0 Comparative Example 1 1 2 1 Comparative Example 2 2 2 2 Comparative Example 3 3 1 2

[0187] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A microemulsified plant soap containing moringa seed active ingredients, characterized in that, This plant-based soap comprises, by weight percentage, 40-70% soap base, 8-18% moringa pod oil, 0.5-3.0% moringa seed protein extract, 4-10% non-soap-based surfactant system, 5-15% polyol, and the balance being water. The soap base is obtained by saponification of at least two of the oils selected from coconut oil, palm kernel oil, palm oil and olive oil, and the mass fraction of unsaponified oil in the soap base is 5-12%. The moringa pod oil is a vegetable oil extracted from a mixture of moringa pods and moringa seeds in a mass ratio of 1 to 3:

1. Moringa seed protein extract is a water-soluble protein obtained from defatted, ungerminated moringa seeds, with a protein mass fraction of 60-90%, and a number-average molecular weight of 0.5-5 kDa as determined by gel permeation chromatography in an aqueous solution at pH 7.

0. The non-soap-based surfactant system consists of C8-C14 alkyl polysaccharides with an average degree of polymerization of 1.3-1.6, cocamidopropyl betaine, and sucrose fatty acid esters and / or polyglycerol fatty acid esters with an HLB value of 12-16, in a mass ratio of (1.5-2.5):(0.8-1.2):(0.5-1.0). Among them, after the plant soap is mixed with deionized water at 25℃ at a mass ratio of 1:10, the transmittance at a wavelength of 600nm is not less than 80%, and the volume average particle size of the oil droplets in the resulting dispersion system is 15-60nm as measured by dynamic light scattering, and the polydispersity index is not higher than 0.

30. The free alkali content of plant soap, calculated as NaOH, is no higher than 0.03%, and the pH value at 25℃ is 6.8 to 7.

8.

2. The microemulsified plant soap containing moringa seed active ingredients according to claim 1, characterized in that, The moringa pod oil contains 40-55% linoleic acid, 4-10% linolenic acid, 0.02-0.3% docosahexaenoic acid, and a total polyunsaturated fatty acid content of not less than 65%. The peroxide value of the moringa pod oil is not higher than 5 mmol / kg, and the total content of volatile sulfur-containing small molecules, calculated as carbon disulfide, is not higher than 5 mg / kg.

3. The microemulsified plant soap containing moringa seed active ingredients according to claim 1, characterized in that, The moringa seed protein extract contains polypeptide fragments with a number average molecular weight of 0.5 to 3 kDa, which account for 70 to 95% of the total polypeptide by mass, and hydrophobic amino acid residues account for 35 to 55% of the total amino acid residue molar fraction.

4. The microemulsified plant soap containing moringa seed active ingredients according to claim 1, characterized in that, The Moringa seed protein extract was prepared through the following steps: (1) Extract defatted Moringa seed powder in an aqueous solution with pH 8.0-9.5 and 25-35℃ at a powder-to-water mass ratio of 1:(10-20) for 30-120 minutes, and centrifuge to remove insoluble matter; (2) Adjust the supernatant after centrifugation to pH 4.2-4.8 to precipitate the protein, then dissolve it in an aqueous solution with pH 7.0-8.0, and enzymatically hydrolyze it for 30-180 minutes at 40-55℃ using 1000-5000 U / g of protein. (3) The enzymatically hydrolyzed solution is sequentially separated by ultrafiltration membrane with a molecular weight cutoff of 10 kDa, ultrafiltration membrane with a molecular weight cutoff of 3 kDa and nanofiltration membrane with a molecular weight cutoff of 0.5 to 1 kDa. The obtained fractions are spray-dried or freeze-dried to obtain the Moringa seed protein extract.

5. The microemulsified plant soap containing moringa seed active ingredients according to claim 1, characterized in that, The moringa seed protein extract was prepared in an aqueous solution at pH 7.0 at a mass concentration of 1.0 mg / mL, and after standing at 25°C for 30 min, it was completely dissolved without producing any visible precipitate. The absorbance of the solution at a wavelength of 212 nm was 0.5–2.

0.

6. The microemulsified plant soap containing moringa seed active ingredients according to claim 1, characterized in that, The mass ratio of Moringa pod oil to Moringa seed protein extract is (15-35):

1.

7. The microemulsified plant soap containing moringa seed active ingredients according to claim 1, characterized in that, The alkyl polysaccharides contain 40-80% C8-C10 alkyl polysaccharides and 20-60% C12-C14 alkyl polysaccharides.

8. A method for preparing a microemulsion plant soap containing moringa seed active ingredients according to any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Soap base preparation: At least two of the following oils, coconut oil, palm kernel oil, palm oil and olive oil, are stirred evenly at 20-30℃ in proportion; prepare sodium hydroxide and / or potassium hydroxide aqueous solution, so that the temperature of the alkali solution does not exceed 30℃, and control the equivalent ratio of alkali to saponifiable fatty acids to be 0.88-0.96:

1. Add the alkali solution slowly to the mixed oil at 20-35℃, maintain a shear rate of 300-800 r / min and saponify for 30-90 min to obtain a saponified slurry with suitable fluidity; let the saponified slurry stand at 20-30℃ for 24-72 h to stabilize the mass fraction of unsaponifiable oil at 5-12% to obtain cold-process soap base; (2) Preparation of Moringa Seed Active Pre-emulsion: At 20-30℃, Moringa seed protein extract was dissolved in a mixed solvent composed of polyol and water to obtain a protein solution, and the pH was adjusted to 6.8-7.5; under stirring conditions, C8-C14 alkyl polysaccharide and cocamidopropyl betaine in a non-soap-based surfactant system were added in sequence, and the protein solution was fully mixed with the above surfactants. Moringa seed oil was slowly added at 25-35℃ and high-speed shear emulsification was carried out for 5-20 min to obtain Moringa seed active pre-emulsion with an average oil droplet volume diameter of no more than 100 nm. (3) Microemulsion plant soap forming: Under the condition of 25-35℃, the soap base obtained in step (1) is added to the mixing tank, and the active pre-emulsion of Moringa pods obtained in step (2) is added in batches under the condition of shear rate of 800-2500r / min. At the same time, the remaining sucrose fatty acid ester and / or polyglycerol fatty acid ester in the non-soap-based surfactant system are added. After mixing for 5-20 min at the above shear rate, the shear rate is adjusted to 200-600r / min and mixing is continued for 5-20 min to form a uniform concentrated microemulsion paste. Subsequently, an aqueous solution of organic acid was added at a temperature not exceeding 30°C to adjust the pH of the system to 6.8–7.

8. The mixture was allowed to stand for 0.5–4 hours to degas, and then the material was injected into a mold and matured at 20–30°C for 24–72 hours to obtain a microemulsified plant soap containing the active ingredients of Moringa pods.

9. The method for preparing the microemulsion plant soap containing moringa seed active ingredients according to claim 8, characterized in that, After the high-speed shear emulsification in step (2) is completed, the Moringa seed active pre-emulsion is adjusted to 25-35°C and slowly stirred for 10-60 minutes at a shear rate of 200-800 r / min before proceeding to step (3).

10. The method for preparing the microemulsion plant soap containing moringa seed active ingredients according to claim 8 or 9, characterized in that, In step (3), microemulsified plant soap is formed by segmented pH adjustment and defoaming under reduced pressure. A mixed aqueous solution of citric acid and lactic acid is first added at 25–30°C to adjust the pH of the system to 7.8–8.

5. After standing for 20–60 minutes, the mixed aqueous solution is added again to adjust the pH to 6.8–7.

8. After pH adjustment, the system is degassed under slight reduced pressure (−0.02–−0.06 MPa) for 5–20 minutes and / or under normal pressure for 0.5–4 hours at a temperature not exceeding 30°C to remove air bubbles. The material is then injected into a mold for curing and shaping.