Plant-derived functional ingredient soft capsule and preparation method thereof

Abstract

The present application belongs to the technical field of soft capsule preparation method, and specifically relates to a plant source functional ingredient soft capsule and a preparation method thereof.The content of the soft capsule comprises, by weight, plant extract powder, micronized anhydrous citric acid, hydrophilic and hydrophobic fumed silica, composite antioxidant mother liquor, medium-chain triglyceride and osmotic pressure microgel symbiotic precursor.The present application is designed by decoupling the surface energy of bimodal silicon, constructs an anti-settling thixotropic network by using hydrophobic silicon, and anchors the powder by using hydrophilic silicon;the trehalose-pectin-calcium symbiotic precursor prepared by mechanical co-milling absorbs the migration water of the gel skin by osmotic pressure and is crosslinked in situ to actively establish a water barrier at the phase interface;the antioxidants are embedded in reverse micelles by thermodynamic quenching, and an electron transfer regeneration cycle is constructed in combination with the citric acid solid-phase proton pool.The present application effectively overcomes the defects of oil phase solid-liquid separation, water intrusion and ingredient oxidation, and improves the physical uniformity and long-term storage stability of the product.

Description

Technical Field

[0001] This invention belongs to the technical field of soft capsule preparation methods, specifically a plant-derived functional ingredient soft capsule and its preparation method. Background Technology

[0002] Plant-derived functional ingredients have wide applications in the field of nutrition and health. Natural plant extracts such as proanthocyanidins, curcumin, and lycopene are usually in powder form, have a natural bitter odor, and are easily destroyed in the gastrointestinal environment. Industrially, these active powders are often dispersed in a non-polar oil matrix and then processed and compressed into soft capsule dosage forms.

[0003] In traditional plant-based functional soft capsule manufacturing processes, the formulation of the content suspension often uses medium-chain triglycerides or soybean oil as the continuous phase. To reduce the risk of high-density plant powders settling due to gravity in the oil phase medium, beeswax is usually melted in during heating or fumed silica is added directly as a physical suspending agent. Considering the generally easy oxidation of plant polyphenols and terpenoids, conventional fat-soluble antioxidants such as vitamin E or L-ascorbic acid palmitate are typically mixed into the oil matrix during production.

[0004] However, improving the wettability of plant powders in the oil phase requires the introduction of surfactants such as soybean lecithin. Their highly polar head groups preferentially occupy the silanol groups on the surface of fumed silica. After compression and molding, the soft capsule shell is in a high-water-content state, and free water spontaneously migrates into the low-water-activity contents driven by osmotic pressure. The non-polar oil environment limits the mass transfer and diffusion efficiency of polar molecules. Even with the addition of conventional water-absorbing substances to the matrix, there is still a significant time lag in water interception and cross-linking at the phase interface. Uncured free water penetrates into the core area and induces accelerated deterioration of water-sensitive components. In conventional antioxidant systems, the solubility of L-ascorbic acid palmitate decreases sharply during the hot-melt cooling process, and the molecules easily aggregate spontaneously and crystallize out in large quantities within the oil phase. Summary of the Invention

[0005] The purpose of this invention is to provide a plant-derived functional ingredient soft capsule and its preparation method, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a plant-derived functional ingredient soft capsule, comprising a capsule shell and a suspension of contents encapsulated within the capsule shell. The suspension of contents, by weight, is made from raw materials comprising the following components: 18.0–25.0 parts of plant-derived functional extract powder, 0.30–1.0 parts of micronized anhydrous citric acid, 0.40–0.70 parts of hydrophilic fumed silica, 8.70–14.30 parts of a composite antioxidant mother liquor, 53.0–56.0 parts of medium-chain triglycerides, 1.1–2.1 parts of hydrophobic fumed silica, and 0.30–0.90 parts of a responsive osmotic pressure microgel symbiotic precursor.

[0007] If fumed silica is used directly as a thickener, soybean lecithin in the system will compete with silanol groups for adsorption due to its amphiphilicity, leading to the collapse of the thickening network. Hydrophobic fumed silica, with its alkyl segments, relies primarily on van der Waals forces and segmental entanglement to build its network framework in a non-polar matrix, thus avoiding adsorption conflicts with the polar head groups of soybean lecithin and establishing a structural base with higher yield stress. A small amount of hydrophilic fumed silica is specifically used to bind with polar groups on the surface of the extract powder, forming stress nodes between the powder particles in the continuous phase network, thereby controlling the gravitational sedimentation of high-concentration particles. Regarding the moisture protection mechanism, the symbiotic precursor located on the periphery of the network, leveraging the osmotic pressure difference between components, can actively capture free water that seeps in through the capsule shell during the soft capsule drying stage. The trapped water then triggers dissociation and coordination reactions within a tiny area, generating a mesh-like water-blocking barrier in situ. This directly cuts off the channels for external water to continue penetrating inward, thus protecting the inner plant active ingredients from hydrolysis and damage.

[0008] Preferably, the responsive osmotic pressure microgel symbiotic precursor is made from raw materials comprising the following parts by weight: 0.15–0.45 parts low-ester pectin, 0.05–0.25 parts calcium lactate or calcium gluconate, and 0.10–0.20 parts anhydrous trehalose. The responsive osmotic pressure microgel symbiotic precursor is prepared by physically co-milling the low-ester pectin, calcium lactate or calcium gluconate, and anhydrous trehalose in a vibratory ball mill at a relative humidity of 10%–14% for 30–40 minutes at 20–25°C.

[0009] By employing the above technical solution, co-milling forces anhydrous trehalose, low-ester pectin, and calcium salts to achieve sufficient physical contact under low humidity. Given the extremely low ion diffusion efficiency in non-polar oil-phase systems, if the components are too far apart, cross-linking reactions will be difficult to trigger upon water penetration. The co-milled components are spatially compressed, allowing anhydrous trehalose to draw surrounding water into the micropowder interface using its strong water-absorbing properties. This infiltrated water can then dissolve calcium salts and hydrate pectin in situ and simultaneously. The released calcium ions then coordinate with the pectin molecular chains. This rapid response characteristic due to the shortened spatial distance overcomes the mass transfer resistance bottleneck in non-polar media, enabling the microgel cross-linking process to occur rapidly in the early stages of water intrusion.

[0010] Preferably, the composite antioxidant mother liquor is made from raw materials comprising the following parts by weight: 5.0-8.0 parts of medium-chain triglycerides, 2.5-4.0 parts of soybean lecithin, 0.80-1.4 parts of L-ascorbyl palmitate, and 0.40-0.90 parts of tocopherol. The preparation method of the composite antioxidant mother liquor is as follows: medium-chain triglycerides, soybean lecithin, and L-ascorbyl palmitate are placed in a reaction vessel, heated to 75-80°C and maintained for 15-25 minutes until molten; then cooling water is introduced into the jacket of the reaction vessel, and the system temperature is reduced to 25-30°C within 10-15 minutes; tocopherol is added and stirred evenly to obtain the final product.

[0011] By employing the above technical solution, the process challenge of L-ascorbate palmitate's easy precipitation in a non-polar oil phase at room temperature is effectively addressed. Conventional heating followed by slow cooling often causes this high-melting-point component to aggregate into coarse crystals, resulting in a loss of dispersibility. This process introduces a rapid cooling step while the system is in a high-temperature molten state, forcing amphiphilic soybean lecithin molecules to rapidly assemble into an inverse micelle morphology in a cold environment. The rapid temperature drop directly disrupts the conditions for L-ascorbate palmitate to form stable crystal nuclei, causing its molecules to be encapsulated and confined in an amorphous state at the microscopic interface of the inverse micelles. This operation not only maintains the uniform dispersion of the antioxidant in the continuous phase medium but also prevents crystal growth from weakening its antioxidant activity, thus improving the antioxidant performance of the contents system during long-term storage.

[0012] Preferably, the micronized anhydrous citric acid adheres to the surface of the plant-derived functional extract powder, and together with L-ascorbate palmitate encapsulated at the reverse micelle interface and tocopherol distributed in the continuous phase, constitutes a proton-coupled electron transfer cycle system.

[0013] By employing the above-mentioned technical solution, tocopherols, after capturing free oxygen free radicals, typically undergo oxidation and lose their protective ability. At this point, additional electron donors are needed for reduction. However, free antioxidant molecules still require proton replenishment to complete the reduction cycle. Anhydrous citric acid, pre-dry-mixed and attached to the surface of the plant powder, provides a solid-phase proton source. When the surrounding soybean lecithin reverse micelles contact the powder surface, the polar channels formed within them guide the protons released by citric acid to the antioxidant depletion area. This relay replenishment of protons and electrons allows easily depleted antioxidants to continuously regenerate and reorganize, extending the overall resistance period of the contents to oxidative environments.

[0014] Secondly, the present invention provides a method for preparing plant-derived functional ingredient soft capsules, comprising the following steps: S1. Add purified water, glycerin and sorbitol to a gelling tank and heat. Then add gelatin, stir under vacuum, set the temperature for later use, and prepare the gelatin liquid. S2. Plant-derived functional extract powder and micronized anhydrous citric acid are added to a mixer and mixed to obtain an inner layer powder mixture. S3. Take the first part of the composite antioxidant mother liquor, spray it through an atomizing nozzle into the inner layer powder mixture obtained in step S2 for stirring and mixing, and then add hydrophilic fumed silica to continue mixing to obtain composite functional powder. S4. Mix the medium-chain triglycerides with the remaining composite antioxidant mother liquor from the second part in a mixing tank, turn on the high-shear dispersion emulsifier, add hydrophobic fumed silica for shear dispersion, then stop stirring and let stand to obtain thixotropic oil gel. S5. Under the stirring action of the anchor stirrer, the responsive osmotic pressure microgel symbiotic precursor and the composite functional powder obtained in step S3 are added to the thixotropic oil gel obtained in step S4 in sequence, and the mixture is stirred and degassed under vacuum to obtain a suspension of contents. S6. The gelatinous liquid prepared in step S1 and the contents suspension prepared in step S5 are fed into a soft capsule press for injection compression. The compressed soft capsules are then transferred to a rotary dryer for drying and shaping to obtain plant-derived functional ingredient soft capsules.

[0015] By adopting the above technical solution, the preparation process of the contents was deconstructed based on the internal functional requirements of the system. Pre-mixing of the powder in step S2 aims to position the solid proton source on the surface of the plant powder, preventing premature loss of citric acid into the overall matrix. In the subsequent step S3, a small amount of mother liquor is introduced to wet and coat the powder, working with hydrophilic silica to establish the surface physical state of the powder. With the interference of polar powder eliminated, step S4 allows for the independent establishment of an anti-settling hydrophobic continuous phase framework through high-shear operation. Drug-loaded suspension processes involving heat-sensitive components are all carried out at room temperature in step S5, avoiding the heating step in the earlier oil phase preparation and reducing the probability of thermal stress damage to components such as polyphenols. In the capsule forming and drying stage, this method utilizes the characteristic of gelatin itself to easily release water outwards, converting the inwardly migrating water into reactants that directly trigger the cross-linking reaction of the symbiotic precursors at the edge of the contents, thereby establishing an inner defense against continuous external moisture intrusion.

[0016] Preferably, in step S3, the weight ratio of the first part of the composite antioxidant mother liquor to the second part of the composite antioxidant mother liquor is 3:7.

[0017] By adopting the above technical solution, the proportion of antioxidant mother liquor in the powder encapsulation and matrix construction stages was rationally determined. The amount of mother liquor used for spray wetting was controlled at 30%, which not only met the actual needs of the extract powder transitioning from a hydrophilic to a partially lipophilic state, but also avoided large-scale agglomeration and wall adhesion of the powder during the mixing stage due to excessive liquid phase addition. The remaining mother liquor was used as part of the formulation in subsequent processes to ensure that the continuous phase has sufficient phospholipid components to maintain the integrity of the oleogel network.

[0018] Preferably, all mixing, shearing and degassing operations in steps S2 to S5 are carried out within a temperature range of 20 to 30°C.

[0019] By adopting the above technical solution, the entire manufacturing process is clearly controlled in terms of temperature. Since extracts such as proanthocyanidins are sensitive to heat sources, the process arrangement only involves pre-heating and dissolving some high-melting-point auxiliary materials. All subsequent core processes involving the mixing, dispersion, and vacuuming of plant powders are confined to a near-room temperature environment. This temperature limitation effectively prevents excessive heat accumulation within the processing system, protecting the relevant polyphenols and terpenes from continuous high-temperature damage from the perspective of production process control.

[0020] Preferably, in step S6, the temperature inside the rotary dryer is set to 20-25°C, the relative humidity is set to 10%-18%, and the drying degree is controlled until the moisture content of the soft capsules reaches 8%-12%.

[0021] By adopting the above technical solution, a relatively gentle dehydration environment is provided for the final shaping of the finished capsules. Setting strict external low temperature and low humidity conditions can guide the moisture in the capsule shell to evaporate more easily into the external environment, thereby moderately slowing down the water flux permeating into the capsule shell. When the flow rate of water permeating into the contents is limited to a lower range, the microgel symbiotic precursor at the boundary has sufficient time to capture and cross-link it; thus reducing the impact of the internal reaction being unable to establish a coherent defense due to the sudden influx of a large amount of water, and consolidating the compactness of the water barrier configuration.

[0022] The present invention has the following beneficial effects: 1. In this invention, hydrophobic fumed silica with alkyl segments is used to construct an anti-settling network in the continuous phase, avoiding the competitive destruction of the thickening skeleton by the polar head groups of soybean phospholipids; simultaneously, a small amount of hydrophilic fumed silica is used to anchor on the surface of the extract powder as a suspension node. This design of separating the rheological network and surface activity enables the contents system to obtain a stable yield stress, effectively controlling the gravity sedimentation of plant functional powders during pelleting and storage, and improving the uniformity of product content and dispersion.

[0023] 2. This invention prepares an osmotic microgel symbiotic precursor by compressing the spatial distance between anhydrous trehalose, low-ester pectin, and calcium salts during high-energy co-milling pretreatment. During the soft capsule shaping and drying stage, this precursor utilizes the hygroscopic driving force of anhydrous trehalose to absorb trace amounts of moisture intruding into the phase interface, and dissolves calcium salts and hydrates pectin in situ within the same micro-space, promoting a coordination reaction between dissociated calcium ions and galacturonic acid residues. This spontaneous cross-linking mechanism generates a dense, water-resistant gel layer at the edge of the contents, cutting off external moisture permeation channels and protecting the water-sensitive plant extracts.

[0024] 3. In this invention, thermodynamic quenching technology is used to force soybean phospholipids to assemble into reverse micelles, and the high-melting-point L-ascorbate palmitate is retained in an amorphous state at its microscopic interface, preventing the precipitation and failure of this component. Simultaneously, a dry-mixing operation is used to attach micronized anhydrous citric acid to the surface of the plant powder as a solid-phase proton source. After capturing free radicals, tocopherols in the system obtain proton compensation from the inner citric acid through the phospholipid reverse micelle channels, and achieve structural reduction and regeneration under the electron donor action of L-ascorbate palmitate. This pathway delays the oxidative degradation process of the overall contents. Attached Figure Description

[0025] Figure 1 This is a flowchart of the preparation method of the present invention; Figure 2 This is a schematic diagram of the feasibility test results of the present invention, wherein (a) is a schematic diagram of the yield stress test results of the thixotropic oleogel, and (b) is a curve of the dynamic water content change of the contents. Figure 3 The diagram shows the test results of the physical suspension stability and production uniformity of the present invention, where (a) is a schematic diagram of the centrifugation accelerated sedimentation rate test results, and (b) is a schematic diagram of the relative standard deviation of the contents of a single particle. Figure 4 The figure shows the results of the comparative test of the chemical stability and antioxidant synergy of the present invention. (a) is a schematic diagram of the change of oil phase peroxide value with aging time, and (b) is a schematic diagram of the change of proanthocyanidin retention rate with aging time. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0028] Hydrophilic fumed silica, CAS number 112945-52-5, is untreated synthetic amorphous silica with a specific surface area of ​​200 m². 2 / g.

[0029] Hydrophobic fumed silica, CAS number 68611-44-9, is a synthetic amorphous silica that has undergone surface modification with dimethyldichlorosilane, and has a specific surface area of ​​110 m² / g. 2 / g; Soybean lecithin, CAS number 8002-43-5, contains phosphatidylcholine at a mass content greater than 60%. Anhydrous citric acid, CAS number 77-92-9, is micronized with a particle size D90 of 2.0μm to 8.0μm. Low-ester pectin, CAS number 9000-69-5, particle size D90 less than 20μm; The CAS number for calcium lactate is 814-80-2, the CAS number for calcium gluconate is 299-28-5, and the CAS number for anhydrous trehalose is 99-20-7.

[0030] The CAS number for medium-chain triglycerides is 73398-61-5; the plant-derived functional extract powder is a combination of one or more of proanthocyanidins, curcumin, lycopene and resveratrol; the CAS number for L-ascorbic acid palmitate is 137-66-6; the CAS number for tocopherol is 1406-66-2; the CAS number for glycerol is 56-81-5; the CAS number for sorbitol is 50-70-4; the CAS number for gelatin is 9000-70-8; and the purified water and other conventional substances are all commercially available products.

[0031] Preparation Example 1: This preparation example provides a method for preparing a responsive osmotic pressure microgel symbiotic precursor, including the following steps: Under the condition of controlling the relative humidity of the environment at 10%, 0.15 parts of low-ester pectin, 0.05 parts of calcium lactate and 0.10 parts of anhydrous trehalose were put into a high-energy vibratory ball mill and subjected to physical co-milling treatment at 20°C for 30 minutes to obtain a responsive osmotic pressure microgel symbiotic precursor. After preparation, it was sealed and kept dry for later use.

[0032] Preparation Example 2: This preparation example provides a method for preparing a responsive osmotic pressure microgel symbiotic precursor, including the following steps: Under the condition of controlling the relative humidity of the environment at 12%, 0.30 parts of low-ester pectin, 0.15 parts of calcium lactate and 0.15 parts of anhydrous trehalose were put into a high-energy vibrating ball mill and subjected to physical co-milling treatment at 22°C for 35 minutes to obtain a responsive osmotic pressure microgel symbiotic precursor. After preparation, it was sealed and kept dry for later use.

[0033] Preparation Example 3: This preparation example provides a method for preparing a responsive osmotic pressure microgel symbiotic precursor, including the following steps: Under the condition of controlling the relative humidity of the environment at 14%, 0.45 parts of low-ester pectin, 0.25 parts of calcium gluconate and 0.20 parts of anhydrous trehalose were put into a high-energy vibratory ball mill and subjected to physical co-milling treatment at 25°C for 40 minutes to obtain a responsive osmotic pressure microgel symbiotic precursor. After preparation, it was sealed and kept dry for later use.

[0034] Preparation Example 4: This preparation example provides a method for preparing a composite antioxidant mother liquor, including the following steps: 5.0 parts of medium-chain triglycerides, 2.5 parts of soybean lecithin, and 0.8 parts of L-ascorbyl palmitate were placed in a jacketed reactor. Stirring was started and the stirring speed was set to 200 rpm. The mixture was heated to 75°C and maintained for 15 minutes. Then, 5°C cooling water was introduced into the reactor jacket to lower the system temperature to 25°C within 10 minutes. After cooling, 0.4 parts of tocopherol were added, and the mixture was stirred for 10 minutes at a stirring speed of 200 rpm to obtain a composite antioxidant mother liquor.

[0035] Preparation Example 5: This preparation example provides a method for preparing a composite antioxidant mother liquor, including the following steps: 6.5 parts of medium-chain triglycerides, 3.2 parts of soybean lecithin, and 1.1 parts of L-ascorbyl palmitate were placed in a jacketed reactor. Stirring was started, and the stirring speed was set to 250 rpm. The mixture was heated to 78°C and maintained for 20 minutes. Then, cooling water at 8°C was introduced into the reactor jacket to lower the system temperature to 28°C within 12 minutes. After cooling, 0.6 parts of tocopherol were added, and the mixture was stirred for 10 minutes at 250 rpm to obtain a composite antioxidant mother liquor.

[0036] Preparation Example 6: This preparation example provides a method for preparing a composite antioxidant mother liquor, including the following steps: 8.0 parts of medium-chain triglycerides, 4.0 parts of soybean lecithin and 1.4 parts of L-ascorbyl palmitate were placed in a jacketed reactor, stirred at 300 rpm, and heated to 80°C for 25 minutes. Then, 10°C cooling water was introduced into the reactor jacket to lower the system temperature to 30°C within 15 minutes. After cooling, 0.9 parts of tocopherol were added, and the mixture was stirred at 300 rpm for 10 minutes to obtain a composite antioxidant mother liquor.

[0037] Reference Figure 1 Example 1: This embodiment provides a method for preparing plant-derived functional ingredient soft capsules, including the following steps: S1. Add 37.5 parts purified water, 8.75 parts glycerin and 8.75 parts sorbitol to a gelling tank, heat to 75°C, add 42.5 parts gelatin, stir for 1.5 hours under a vacuum of -0.08MPa, and set the holding temperature to 60°C for later use. S2. Add 21.5 parts of proanthocyanidin powder and 0.65 parts of anhydrous citric acid into a three-dimensional mixer and mix at 25°C for 30 minutes to obtain an inner layer powder mixture. S3. Take 3.42 parts of the composite antioxidant mother liquor prepared in Preparation Example 5 and spray it into the inner layer powder mixture obtained in step S2 through an atomizing nozzle. Turn on the mixer and mix for 25 minutes at a stirring speed of 60 rpm. Add 0.55 parts of hydrophilic fumed silica and mix for 20 minutes at a stirring speed of 60 rpm to obtain the composite functional powder. S4. Mix 54.5 parts of medium-chain triglycerides and 7.98 parts of the composite antioxidant mother liquor prepared in Preparation Example 5 in a mixing tank. Set the system temperature to 28°C, turn on the high-shear dispersing emulsifier, set the speed to 3500 rpm, add 1.6 parts of hydrophobic fumed silica, shear for 18 minutes, stop stirring, and let stand for 30 minutes to obtain thixotropic oil gel. S5. Set the temperature of the thixotropic oleogel obtained in step S4 to 25°C, turn on the anchor stirrer, set the speed to 50 rpm, and add 0.60 parts of the responsive osmotic pressure microgel symbiotic precursor prepared in Preparation Example 2 and the composite functional powder obtained in step S3 in sequence. Stir and degas for 40 minutes under a vacuum of -0.08 MPa to obtain a suspension of contents. S6. The gelatinous liquid prepared in step S1 and the contents suspension prepared in step S5 are fed into a soft capsule press for injection compression. The compressed soft capsules are transferred to a rotary dryer and dried at a temperature of 25°C and a relative humidity of 15% until the moisture content of the soft capsules reaches 10%, thus obtaining plant-derived functional ingredient soft capsules.

[0038] Example 2: This embodiment provides a method for preparing plant-derived functional ingredient soft capsules, including the following steps: S1. Add 35.0 parts purified water, 7.5 parts glycerol and 7.5 parts sorbitol to a gelling tank, heat to 70°C, add 40.0 parts gelatin, stir for 1 hour under a vacuum of -0.06MPa, and set the heat preservation temperature to 55°C for later use. S2. Add 18.0 parts of proanthocyanidin powder and 0.30 parts of anhydrous citric acid into a three-dimensional mixer and mix at 20°C for 25 minutes to obtain an inner layer powder mixture. S3. Take 2.61 parts of the composite antioxidant mother liquor prepared in Preparation Example 4 and spray it into the inner layer powder mixture obtained in step S2 through an atomizing nozzle. Turn on the mixer and mix for 20 minutes at a stirring speed of 50 rpm. Add 0.40 parts of hydrophilic fumed silica and mix for 15 minutes at a stirring speed of 50 rpm to obtain the composite functional powder. S4. Mix 53.0 parts of medium-chain triglycerides and 6.09 parts of the composite antioxidant mother liquor prepared in Preparation Example 4 in a mixing tank. Set the system temperature to 25°C, turn on the high-shear dispersing emulsifier, set the speed to 3000 rpm, add 1.1 parts of hydrophobic fumed silica, shear for 15 minutes, stop stirring, and let stand for 25 minutes to obtain thixotropic oil gel. S5. Set the temperature of the thixotropic oleogel obtained in step S4 to 20°C, turn on the anchor stirrer, set the speed to 40 rpm, and add 0.30 parts of the responsive osmotic pressure microgel symbiotic precursor prepared in Preparation Example 1 and the composite functional powder obtained in step S3 in sequence. Stir and degas for 30 minutes under a vacuum of -0.06 MPa to obtain a suspension of contents. S6. The gelatinous liquid prepared in step S1 and the contents suspension prepared in step S5 are fed into a soft capsule press for injection compression. The compressed soft capsules are transferred to a rotary dryer and dried at a temperature of 20°C and a relative humidity of 10% until the moisture content of the soft capsules reaches 8%, thus obtaining plant-derived functional ingredient soft capsules.

[0039] Example 3: This embodiment provides a method for preparing plant-derived functional ingredient soft capsules, including the following steps: S1. Add 40.0 parts purified water, 10.0 parts glycerol and 10.0 parts sorbitol to a gelling tank, heat to 80°C, add 45.0 parts gelatin, stir for 2 hours under a vacuum of -0.08MPa, and set the heat preservation temperature to 65°C for later use. S2. Add 25.0 parts of curcumin powder and 1.0 part of anhydrous citric acid into a three-dimensional mixer and mix at 25°C for 35 minutes to obtain an inner layer powder mixture. S3. Take 4.29 parts of the composite antioxidant mother liquor obtained in Preparation Example 6 and spray it into the inner layer powder mixture obtained in step S2 through an atomizing nozzle. Turn on the mixer and mix for 30 minutes at a stirring speed of 80 rpm. Add 0.70 parts of hydrophilic fumed silica and mix for 20 minutes at a stirring speed of 80 rpm to obtain the composite functional powder. S4. Mix 56.0 parts of medium-chain triglycerides and 10.01 parts of the composite antioxidant mother liquor prepared in Preparation Example 6 in a mixing tank. Set the system temperature to 30°C, turn on the high-shear dispersing emulsifier, set the speed to 4000 rpm, add 2.1 parts of hydrophobic fumed silica, shear for 20 minutes, stop stirring, and let stand for 35 minutes to obtain thixotropic oil gel. S5. Set the temperature of the thixotropic oleogel obtained in step S4 to 25°C, turn on the anchor stirrer, set the speed to 60 rpm, and add 0.90 parts of the responsive osmotic pressure microgel symbiotic precursor prepared in Preparation Example 3 and the composite functional powder obtained in step S3 in sequence. Stir and degas for 45 minutes under a vacuum of -0.08 MPa to obtain a suspension of contents. S6. The gelatinous liquid prepared in step S1 and the contents suspension prepared in step S5 are fed into a soft capsule press for injection compression. The compressed soft capsules are transferred to a rotary dryer and dried at a temperature of 25°C and a relative humidity of 18% until the moisture content of the soft capsules reaches 12%, thus obtaining plant-derived functional ingredient soft capsules.

[0040] Example 4: This embodiment provides a method for preparing plant-derived functional ingredient soft capsules, including the following steps: S1. Add 38.0 parts purified water, 8.0 parts glycerol and 8.0 parts sorbitol to a gelling tank, heat to 75°C, add 42.0 parts gelatin, stir for 1.5 hours under a vacuum of -0.07MPa, and set the holding temperature to 60°C for later use. S2. Add 20.0 parts by mass of lycopene and resveratrol mixed powder in a 1:1 ratio and 0.50 parts of anhydrous citric acid into a three-dimensional mixer and mix at 22°C for 30 minutes to obtain an inner layer powder mixture. S3. Take 3.42 parts of the composite antioxidant mother liquor prepared in Preparation Example 5 and spray it into the inner layer powder mixture obtained in step S2 through an atomizing nozzle. Turn on the mixer and mix for 25 minutes at a stirring speed of 60 rpm. Add 0.50 parts of hydrophilic fumed silica and mix for 18 minutes at a stirring speed of 60 rpm to obtain the composite functional powder. S4. Mix 53.5 parts of medium-chain triglycerides and 7.98 parts of the composite antioxidant mother liquor prepared in Preparation Example 5 in a mixing tank. Set the system temperature to 28°C, turn on the high-shear dispersing emulsifier, set the speed to 3500 rpm, add 1.5 parts of hydrophobic fumed silica, shear for 18 minutes, stop stirring, and let stand for 30 minutes to obtain thixotropic oil gel. S5. Set the temperature of the thixotropic oleogel obtained in step S4 to 22°C, turn on the anchor stirrer, set the speed to 50 rpm, and add 0.60 parts of the responsive osmotic pressure microgel symbiotic precursor prepared in Preparation Example 2 and the composite functional powder obtained in step S3 in sequence. Stir and degas for 40 minutes under a vacuum of -0.07 MPa to obtain a suspension of contents. S6. The gelatinous liquid prepared in step S1 and the contents suspension prepared in step S5 are fed into a soft capsule press for injection pressing. The pressed soft capsules are transferred to a rotary dryer and dried at a temperature of 22°C and a relative humidity of 15% until the moisture content of the soft capsules reaches 10%, thus obtaining plant-derived functional ingredient soft capsules.

[0041] Comparative Example 1: Compared with Example 1, the difference is that: instead of preparing a responsive osmotic microgel symbiotic precursor in advance, in step S5, equal parts by mass of low-ester pectin powder, calcium lactate powder and anhydrous trehalose powder are directly added to the thixotropic oleogel for mixing, and the remaining steps are the same.

[0042] Comparative Example 2: Compared with Example 1, the difference is that anhydrous trehalose was not added when preparing the responsive osmotic microgel symbiotic precursor; only low-ester pectin and calcium lactate were co-milled, and the remaining steps were the same.

[0043] Comparative Example 3: Compared with Example 1, the difference is that when preparing the composite antioxidant mother liquor, after heating and melting, the rapid cooling and quenching operation with cooling water is not performed. Instead, it is placed in a room temperature environment and allowed to cool slowly to 25°C. The remaining steps are the same.

[0044] Comparative Example 4: The difference from Example 1 is that anhydrous citric acid is not added in step S2, while the other steps are the same.

[0045] Comparative Example 5: Compared with Example 1, the difference is that anhydrous citric acid is not dry-blended with proanthocyanidin powder in step S2, but is directly added to the medium-chain triglyceride continuous phase in the mixing tank in step S4. The remaining steps are the same.

[0046] Comparative Example 6: Compared with Example 1, the difference is that in step S4, the hydrophobic fumed silica is replaced with an equal mass fraction of hydrophilic fumed silica in the continuous phase network construction, while the other steps are the same.

[0047] Comparative Example 7: Compared with Example 1, the difference is that the contents suspension formulation does not contain anhydrous citric acid, responsive osmotic microgel symbiotic precursor, composite antioxidant mother liquor, and hydrophilic-hydrophobic dual-state fumed silica; steps S2 to S5 are replaced by directly stirring and mixing 21.5 parts of proanthocyanidin powder, 54.5 parts of medium-chain triglycerides, 3.0 parts of beeswax and 1.0 parts of tocopherol, cooling and degassing to obtain the contents suspension, and the remaining steps are the same.

[0048] Test Example 1: The purpose of this experiment was to verify the effectiveness of various processes in constructing an anti-settling network in the oil phase by measuring macroscopic physical parameters. The test subjects were the corresponding products of each stage of Example 1, Comparative Example 1, and Comparative Example 6.

[0049] Test steps: 1. Take 50g of each of the thixotropic oleogels obtained in step S4 of Example 1, Comparative Example 1, and Comparative Example 6 respectively, and perform constant shear rate scanning tests using a rotational rheometer equipped with a parallel plate clamp at a test temperature of 25°C. Record the critical stress data when the system transitions from solid elastic deformation to liquid viscous flow to determine the yield stress of each group of samples.

[0050] 2. Collect soft capsule samples from Examples 1, Comparative Examples 1 and 6 that have just completed step S6 injection pressing but have not yet entered the rotary drying process. Place all samples in a constant temperature and humidity test chamber, setting the ambient temperature to 25°C and the relative humidity to 60% to simulate an extreme moisture permeation mass transfer environment.

[0051] 3. After being placed in a constant temperature and humidity environment, at 0, 2, 4 and 8 hours, each group of soft capsule samples were taken out of the test chamber. The gelatin shell was quickly cut open with a scalpel, and the contents of the internal suspension were squeezed out and collected in a centrifuge tube. The tube was centrifuged at 4000 rpm for 5 minutes to separate any trace amounts of gelatin fragments that may have been mixed in.

[0052] 4. Take 2g of each of the above-mentioned centrifuged contents samples, use a fully automatic Karl Fischer moisture analyzer to detect the actual water content percentage inside the suspension, and record the water penetration accumulation at different placement time points.

[0053] The test data is shown in Table 1.

[0054] Table 1: Test results of yield stress and dynamic moisture content of thixotropic oleogels

[0055] Reference Figure 2 As shown in Table 1, the thixotropic oleogel of Example 1 exhibits a higher yield stress value. In Comparative Example 6, fumed silica with surface silanol groups was used in the continuous phase network construction stage. The polar head groups of soybean lecithin in the system competitively adsorbed with it, resulting in steric hindrance. This affected the silanol-dependent framework structure, macroscopically manifested as a lower yield stress value. Example 1, through the design of separating hydrophilic and hydrophobic interfaces, utilized surface-alkylated fumed silica to build a network in a non-polar matrix based on van der Waals forces and chain segment entanglement, reducing the interfacial tension conflict introduced by surfactants and improving the ability of the oil phase system to suspend particles.

[0056] Regarding the verification results of the water-proofing mechanism, Comparative Example 1 did not perform co-milling pretreatment on the microgel precursor and directly dispersed the components in the oil phase. Due to the limited mass transfer and diffusion efficiency in the non-polar medium, the rate at which free water molecules contacted and dissolved calcium salts and pectin decreased, and the microgelation response exhibited a certain hysteresis. As the exposure time progressed, water on the gel side permeated into the contents. In Example 1, the osmotic pressure microgel symbiotic precursor, after contacting free water, utilized the water absorption potential difference within the substrate to absorb water at the interface and dissociate calcium ions, promoting the coordination crosslinking of low-ester pectin galacturonic acid residues and forming a water-blocking barrier at the edge of the oil phase. Under 8 hours of high humidity exposure, the water content of the contents remained at a low level.

[0057] Comparative Example 6, due to the disruption of the matrix rheological network structure, exhibits a lower spatial binding resistance of the continuous phase and an increased diffusion flux of water at the oil phase interface, resulting in a higher water increase. The trend in this data reflects the synergistic effect of rheological properties and the interphase osmotic pressure response mechanism within the system, with the rheological network providing the structural basis for the establishment of the microgel layer.

[0058] Test Example 2: The purpose of this experiment was to compare the performance of a dual-state silicon-based decoupled network with that of a single thickening system in maintaining the uniformity of solid-liquid phase distribution and ensuring consistent filling volume by quantifying the sedimentation rate and the relative standard deviation of the filling volume. The test subjects were the contents and soft capsules prepared in Examples 1 to 4, as well as Comparative Examples 6 and 7.

[0059] Test steps: 1. Take 30g of the contents suspension obtained in the corresponding preparation steps of Examples 1 to 4, Comparative Examples 6 and 7 respectively, transfer the suspension into a graduated centrifuge tube, place it in a benchtop high-speed centrifuge, and run it for 35 minutes at a set speed of 3500 rpm to simulate the sedimentation effect of gravity on the solid and liquid phases.

[0060] 2. After the centrifugation program is completed, remove the centrifuge tube and use a micropipette to remove the oil phase liquid from the top of the centrifuge tube. Transfer the solid precipitate at the bottom of the centrifuge tube to an analytical balance and weigh it. Calculate the percentage of accelerated sedimentation rate of the sample using the ratio of the mass of the precipitate to the total mass of the initial suspension.

[0061] 3. Start the soft capsule compression machine, introduce the suspensions of each group's contents and the matching gelatinous liquid, and perform continuous injection compression. After the soft capsule compression machine has been running continuously for 20 minutes, randomly select 120 soft capsules from each group at the discharge port to evaluate the consistency of the filling weight.

[0062] 4. Select 100 intact soft capsules from the collected samples. Weigh the initial total weight of the soft capsules using an analytical balance. Then, cut open the outer shell with a scalpel to squeeze out the internal suspension. Wash away any residual grease inside the empty capsules using hexane solvent and air dry at room temperature. Weigh the dried empty capsules again. Calculate the content of the contents inside the soft capsules using the two weighings. Summarize the data from the 100 samples to calculate the relative standard deviation of the content.

[0063] The test data is shown in Table 2.

[0064] Table 2: Test Results of Relative Standard Deviation between Centrifugation Accelerated Sedimentation Rate and Single Particle Contents

[0065] Reference Figure 3 Compared with the data in Table 2, Comparative Example 6 exhibits a higher centrifugal sedimentation rate and relative standard deviation of fill weight. Comparative Example 6 used unmodified hydrophilic fumed silica when constructing the non-polar oil phase anti-sedimentation network. Soybean lecithin molecules in the formulation adsorbed on the surface of the hydrophilic silica, affecting the supporting framework established by hydrogen bonds between silica particles, thus weakening the suspension effect of the continuous phase fluid on the plant extract particles. Solid particles settled and aggregated under centrifugal force, resulting in uneven distribution in the feeding pipeline of the soft capsule press. Fluctuations in the solid-liquid ratio drawn in by the injection pump were reflected in the weight deviation of the finished capsules.

[0066] Comparative Example 7 uses a beeswax suspension system, which provides a certain degree of resistance to sedimentation. After the beeswax melt cools down, the apparent viscosity of the system tends to increase. When this type of fluid passes through the narrow injection nozzle of the soft capsule compression machine, it encounters shear friction resistance, and the material flow rate changes, which affects the consistency of the filling amount.

[0067] The sedimentation rates and relative standard deviations of Examples 1 to 4 are within a low range, demonstrating the role of the dual-state silicon-based decoupling mechanism in suspension stability and rheological control. The hydrophobic fumed silica used in these examples forms a network framework in a non-polar matrix through van der Waals forces between surface alkyl segments and physical entanglement with solvent molecules, without significant interference from soybean phospholipid molecules. The hydrophilic fumed silica distributed on the surface of the plant functional powder acts as an anchoring node between the powder particles and the continuous phase framework.

[0068] When faced with centrifugal force, the suspension of contents exhibits a corresponding yield resistance, which delays the gravity-induced phase change sedimentation process. When it is drawn into the injection pump and subjected to mechanical shear force, the entangled chain segments undergo temporary disintegration, resulting in a decrease in apparent viscosity, which is conducive to the fluid filling the metering chamber. After the injection action is completed, the shear force disappears, the network structure is reorganized and restored to a support state, ensuring the continuity of feeding and the stability of the filling volume.

[0069] Test Example 3: The purpose of this experiment was to construct a constant temperature and humidity accelerated aging environment to compare the effects of different combinations of spatial decoupling mechanisms and antioxidant pathways on the retention rate of polyphenolic compounds and the formation rate of primary oxidation products of the lipid matrix. Soft capsules prepared in Examples 1, 2, 3, 4, 5, and 7 were selected as test subjects.

[0070] Test steps: 1. From each batch of qualified and dried soft capsules, 300 capsules were randomly selected as samples. The sampled capsules were laid flat in an open glass petri dish and transferred to a constant temperature and humidity test chamber. The internal environmental parameters of the test chamber were set to a temperature of 40℃ and a relative humidity of 75% to simulate accelerated aging storage conditions for 3 months.

[0071] 2. At the end of the 0th, 1st, 2nd and 3rd month of exposure, 50 soft capsules of each group were taken out from the test chamber, the capsule shells were cut open with a scalpel, the internal suspension was squeezed and collected into centrifuge tubes, and centrifuged at 5000 rpm for 10 minutes at 4°C to separate the solid phase powder particles from the oil phase matrix.

[0072] 3. Take the upper oil phase obtained by centrifugation and perform titration analysis using sodium thiosulfate standard solution in accordance with the titration operation procedure specified in national standard GB 5009.227. Calculate the peroxide value of each group of oil phase matrix and evaluate the degree of oxidative rancidity of the oil continuous phase.

[0073] 4. Collect the compacted solid precipitate at the bottom of the centrifuge tube, and extract it by ultrasonic extraction with a methanol-water mixed solvent under light-protected conditions. After filtering the extract through a microporous membrane, inject it into a high-performance liquid chromatograph. Measure the peak area of ​​proanthocyanidins in the extract at a specific absorption wavelength. Compare the measured value with the peak area of ​​the initial sample to obtain the percentage of proanthocyanidin mass retention in each cycle.

[0074] The test data is shown in Table 3.

[0075] Table 3: Results of oil phase peroxide value and proanthocyanidin retention rate under accelerated aging conditions

[0076] Reference Figure 4According to the data in Table 3, under accelerated aging conditions, the oil phase peroxide value in Examples 1 and 2 remained at a low level, and the proanthocyanidin retention rate showed a gradual decline. Comparative Example 7 used a basic conventional formulation, and the peroxide value rose rapidly in the early stages of testing, correspondingly decreasing the proanthocyanidin retention rate. Due to the lack of interfacial isolation and multiple electron donor structures, lipid peroxidation directly consumed the internal components of this system.

[0077] The suspension system of the embodiment has a microgel structure on the periphery of the oil phase, which slows down the process of environmental moisture penetrating into the deep oil and powder, and reduces the initial triggering probability of hydrolysis and oxidation reactions; the active ingredients inside the contents are in a low redox potential environment, and their concentration loss is controlled within a limited range over a long period of time.

[0078] In Comparative Example 3, without rapid cooling, ascorbate palmitate readily aggregated and precipitated during the slow cooling of the matrix, altering its distribution at the phospholipid reverse micelles and oil-water interface. This change in spatial distribution affected the contact and reduction efficiency between this type of antioxidant and tocopherol free radicals, disrupting the designed primary free radical scavenging chains within the system. This was reflected in the increasing peroxide value data in the later stages of the test, accompanied by the degradation of plant components. In the Example 3, quenching was used to maintain the amorphous state of ascorbate palmitate, preserving its dispersibility in the continuous medium and its probability of participating in the reaction.

[0079] Comparative Example 4 did not add anhydrous citric acid, while Comparative Example 5 changed the method of adding anhydrous citric acid. The antioxidant performance of both groups was inferior to that of the Example 1 in the later stages of the test. Free antioxidant molecules undergo a state transition after participating in free radical neutralization reactions, and their reduction and regeneration process depends on the supply of protons within the system. The Example 1 attached anhydrous citric acid to the surface of the plant powder through dry mixing, combining it with the reverse micelle structure of the outer soybean phospholipid layer, providing a pathway for proton dissociation and transport, and supplying protons to the reaction consumption sites at the interface. Comparative Examples 4 and 5 lacked this substrate-localized and proton-directed replenishment microenvironment; the electron donors within the system were gradually consumed during the reaction, shortening the maintenance time of the chemical protection network, which was reflected in the decline of relevant test indicators in the later stages of aging.

[0080] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A soft capsule containing a plant-derived functional ingredient, comprising a capsule shell and a suspension of contents encapsulated within the capsule shell, characterized in that, The contents suspension, by weight, is made from raw materials comprising the following components: Plant-derived functional extract powder: 18.0–25.0 parts; Anhydrous citric acid: 0.30–1.0 parts; Hydrophilic fumed silica: 0.40–0.70 parts; Compound antioxidant mother liquor: 8.70–14.30 parts; Medium-chain triglycerides: 53.0–56.0 parts; Hydrophobic fumed silica: 1.1–2.1 parts; Response-type osmotic pressure microgel symbiotic precursor: 0.30–0.90 parts.

2. The plant-derived functional ingredient soft capsule according to claim 1, characterized in that, The responsive osmotic microgel symbiotic precursor is made from the following raw materials in parts by weight: 0.15-0.45 parts of low-ester pectin, 0.05-0.25 parts of calcium lactate or calcium gluconate, and 0.10-0.20 parts of anhydrous trehalose; The preparation method of the responsive osmotic pressure microgel symbiotic precursor is as follows: under the condition of controlling the relative humidity of the environment at 10% to 14%, the low-ester pectin, the calcium lactate or calcium gluconate and the anhydrous trehalose are put into a vibratory ball mill and subjected to physical co-milling treatment at a temperature of 20 to 25°C for 30 to 40 minutes to obtain the precursor.

3. The plant-derived functional ingredient soft capsule according to claim 1, characterized in that, The composite antioxidant mother liquor is made from the following raw materials in parts by weight: 5.0-8.0 parts of medium-chain triglycerides, 2.5-4.0 parts of soybean lecithin, 0.80-1.4 parts of L-ascorbic acid palmitate, and 0.40-0.90 parts of tocopherol; The preparation method of the composite antioxidant mother liquor is as follows: the medium-chain triglycerides, soybean lecithin and L-ascorbic acid palmitate are placed in a reaction vessel, heated to 75-80°C and maintained for 15-25 minutes until they are in a molten state; then cooling water is introduced into the jacket of the reaction vessel, and the system temperature is reduced to 25-30°C within 10-15 minutes; the tocopherol is added and stirred evenly to obtain the final product.

4. The plant-derived functional ingredient soft capsule according to claim 1, characterized in that, The rubber sheet is made from the following raw materials in parts by weight: 35.0-40.0 parts purified water, 7.5-10.0 parts glycerin, 7.5-10.0 parts sorbitol and 40.0-45.0 parts gelatin.

5. The plant-derived functional ingredient soft capsule according to claim 1, characterized in that, The plant-derived functional extract powder is a combination of one or more of proanthocyanidins, curcumin, lycopene and resveratrol; the anhydrous citric acid has a particle size D90 of 2.0 μm to 8.0 μm.

6. A method for preparing plant-derived functional ingredient soft capsules, used to prepare the plant-derived functional ingredient soft capsules according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Add purified water, glycerin and sorbitol to a gelling tank and heat. Then add gelatin, stir under vacuum, set the temperature for later use, and prepare the gelatin liquid. S2. Plant-derived functional extract powder and anhydrous citric acid are added to a mixer and mixed to obtain an inner layer powder mixture. S3. Take the first part of the composite antioxidant mother liquor, spray it through an atomizing nozzle into the inner layer powder mixture obtained in step S2 for stirring and mixing, and then add hydrophilic fumed silica to continue mixing to obtain composite functional powder. S4. Mix the medium-chain triglycerides with the remaining composite antioxidant mother liquor from the second part in a mixing tank, turn on the high-shear dispersion emulsifier, add hydrophobic fumed silica for shear dispersion, then stop stirring and let stand to obtain thixotropic oil gel. S5. Under the stirring action of the anchor stirrer, the responsive osmotic pressure microgel symbiotic precursor and the composite functional powder obtained in step S3 are added to the thixotropic oil gel obtained in step S4 in sequence, and the mixture is stirred and degassed under vacuum to obtain a suspension of contents. S6. The gelatinous liquid prepared in step S1 and the contents suspension prepared in step S5 are fed into a soft capsule press for injection compression. The compressed soft capsules are then transferred to a rotary dryer for drying and shaping to obtain plant-derived functional ingredient soft capsules.

7. The method for preparing plant-derived functional ingredient soft capsules according to claim 6, characterized in that, In step S1, the heating temperature is 70-80℃, the vacuum degree is -0.06--0.08MPa, the stirring time is 1.0-2.0 hours, and the heat preservation temperature is set to 55-65℃.

8. The method for preparing plant-derived functional ingredient soft capsules according to claim 6, characterized in that, In step S2, the mixing temperature is 20-25°C and the mixing time is 25-35 minutes; In step S3, the weight ratio of the first part of the composite antioxidant mother liquor to the second part of the composite antioxidant mother liquor is 3:7; the stirring speed after spraying is 50-80 rpm, and the mixing time is 20-30 minutes; the stirring speed after adding hydrophilic fumed silica is 50-80 rpm, and the mixing time is 15-20 minutes.

9. The method for preparing plant-derived functional ingredient soft capsules according to claim 6, characterized in that, In step S4, the temperature in the mixing tank is set to 25-30°C, the speed of the high shear dispersion emulsifier is set to 3000-4000 rpm, the shearing time is 15-20 minutes, and the settling time is 25-35 minutes.

10. The method for preparing plant-derived functional ingredient soft capsules according to claim 6, characterized in that, In step S5, the temperature of the thixotropic oil gel is set to 20-25°C, the speed of the anchor stirrer is set to 40-60 rpm, the degassing vacuum degree is -0.06 to -0.08 MPa, and the stirring and degassing time is 30-45 minutes; in step S6, the temperature inside the rotary drum dryer is 20-25°C, the relative humidity is 10%-18%, and the degree of drying is controlled until the moisture content of the soft capsules reaches 8%-12%.

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