Composite particle containing antioxidant as well as preparation method and application of composite particle

Abstract

The invention discloses composite particles containing an antioxidant as well as a preparation method and application of the composite particles. The composite particle comprises ethyl cellulose and lipidosome formed by coating curcumin with lecithin, the ethyl cellulose and the curcumin lipidosome interact through non-covalent acting force, and a porous structure of the ethyl cellulose provides binding sites for the curcumin lipidosome. The curcumin entrapment efficiency of the composite particles is greatly improved, and the composite particles have excellent thermal stability and storage stability, and can resist too early large inactivation of curcumin caused by gradual increase of temperature during gel preparation, and improve the gel oxidation stability during later high-temperature continuous heating and long-term storage.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and in particular relates to composite particles containing an antioxidant, a preparation method thereof, and an application thereof. Background Art

[0002] As one of the most important and indispensable players in food formulation, fats bring pleasant flavor, taste, texture, and aroma to pre-processed foods, while also providing essential nutrients to consumers. Edible lipids can be divided into fats and oils based on their physicochemical characteristics. At room temperature, fats with a high saturated fatty acid content are solid, while oils with a high unsaturated fatty acid content are liquid. In the food manufacturing industry, fats often exhibit superior processing properties than oils, so they are often used as texture modifiers for foods. This is attributed to the fact that the crystal structure, rheology, and thermal behavior of fats can be adjusted according to production requirements, and good texture conditions are one of the determining factors for the sensory enjoyment of food.

[0003] However, fat sources are limited and expensive, leading to the emergence of production technologies that convert readily available and inexpensive vegetable oils into fats. To date, the industry has developed a variety of conversion methods, with hydrogenation, transesterification, and fractionation being the mainstream. These converted fats are widely used in everyday foods, such as baked goods, seasonings, and processed meats. Notably, these converted fats lose their inherently beneficial unsaturated fatty acids and are replaced by saturated and trans fatty acids. Clinical nutrition and epidemiological studies indicate that long-term high intakes of saturated and trans fatty acids can be detrimental to human health, increasing the risk of chronic diseases such as cardiovascular disease (CVD), type 2 diabetes, and metabolic syndrome (MetS). Countries around the world are implementing measures to alleviate the public health challenges associated with unbalanced dietary fat intake. Denmark, in 2004, introduced regulations limiting the trans fatty acid content in processed foods to a maximum of 2g per 100g of lipid. In 2015, the U.S. Food and Drug Administration (FDA) removed trans fats from the Generally Recognized as Safe (GRAS) list and mandated a complete ban on partially hydrogenated vegetable oils in food formulations starting in 2020. To comply with these regulations and meet consumers' growing demand for healthier foods, the food industry is searching for "solid fat analogs" that can eliminate trans fats from food while reducing saturated fat content without compromising texture or sensory properties.

[0004] Oleogel technology can convert vegetable oils into solid fats with zero trans fatty acids and high levels of unsaturated fatty acids. Therefore, oleogels have become a promising "fat substitute" due to their nutritional and safety properties. Oleogels are typically composed of vegetable oils and a small amount of oleogelating agent. They are thermoreversible, semisolid lipid mixtures with strong viscoelastic properties. Ethylcellulose (EC) acts as a gelling agent, directly structuring the liquid oil without the need for indirect processing such as high-speed shearing or homogenization. During the gelation process, EC reaches its glass transition temperature (Tg), typically between 140-160°C. Upon cooling, the dissolved polymer chains transition from a flexible state to a rigid state, and the re-formed intermolecular hydrogen bonds create an interlaced polymer network that stabilizes the liquid oil. The oil remains in its physical state, remaining in the polymer network to form an oleogel. However, even with short-term high-temperature heating, the presence of unsaturated bonds in some unsaturated vegetable oils, such as linseed oil, can lead to peroxidation of fatty acids, producing toxic chemicals.

[0005] Phytochemicals are active ingredient extracts derived from natural plants. Curcumin, derived from the rhizome of the natural plant turmeric, is a lipophilic polyphenolic plant compound that not only exhibits anti-free radical, anti-inflammatory, and anti-cancer effects but also effectively slows lipid oxidation. Therefore, the development of oil gels containing natural phytochemicals is of practical significance and is crucial for promoting balanced lipid intake and maintaining individual health. However, curcumin is sensitive to high temperatures and continuous heating, which can lead to its own degradation and loss of antioxidant activity.

[0006] Providing composite particles with excellent thermal stability and storage stability, which can resist the gradual increase in temperature during gel preparation and cause premature and substantial inactivation of curcumin, and improve the oxidative stability of the gel during subsequent high-temperature continuous heating and long-term storage, as well as their preparation method and application, has great industrial value. Summary of the Invention

[0007] The present invention aims to solve one of the technical problems existing in the prior art to at least a certain extent. To this end, the present invention provides composite particles containing an antioxidant, a preparation method thereof, and an application thereof.

[0008] According to one aspect of the present invention, a composite particle containing an antioxidant is provided, wherein the composite particle comprises ethyl cellulose and liposomes formed by encapsulating curcumin in lecithin, wherein the ethyl cellulose interacts with the curcumin liposomes through non-covalent forces, and the porous structure of the ethyl cellulose provides binding sites for the curcumin liposomes.

[0009] According to another aspect of the present invention, an antioxidant-containing oil gel is provided, comprising the above-mentioned composite particles, wherein the composite particles are dispersed in linseed oil to form a gel network, and the gel network comprises hydrogen bonding energy between ethyl cellulose polymers and van der Waals bonding energy between linseed oil, lecithin, and ethyl cellulose.

[0010] According to another aspect of the present invention, a method for preparing composite particles containing antioxidants is provided, comprising: dissolving lecithin, cholesterol, and curcumin in ethanol, stirring, and injecting a pH buffer solution; adding ethyl cellulose after stirring; removing the solvent by rotary evaporation after stirring; and vacuum drying to obtain the composite particles.

[0011] Preferably, the volume concentration of ethanol in the control system is 30%-45% (v / v), and the weight ratio of lecithin to ethyl cellulose is 9%-13%.

[0012] Preferably, the volume concentration of ethanol in the control system is 40% (v / v), and the weight ratio of lecithin to ethyl cellulose is 12%.

[0013] Preferably, the pH buffer is a phosphate buffer with a pH of 7.2.

[0014] Preferably, lecithin, cholesterol and curcumin are mixed and dissolved in ethanol, and after stirring, pH buffer solution is injected at a rate of 1 drop per second, and stirred at 25° C. and 600 rpm for 30 minutes.

[0015] Preferably, the lecithin is soybean lecithin, and soybean lecithin, cholesterol and curcumin are mixed in a weight ratio of 10:2:1, dissolved in anhydrous ethanol, and stirred at room temperature for 30 minutes.

[0016] According to another aspect of the present invention, a method for preparing an antioxidant-containing oil gel is provided, comprising: mixing the composite particles described above with linseed oil to form a uniform dispersion; heating the dispersion in a sealed reaction vessel to a target temperature above the glass transition temperature of ethyl cellulose; and then cooling the dispersion; wherein the heating environment is dry and oxygen-free.

[0017] Preferably, a high boiling point organosilicon heat transfer medium is used for heating.

[0018] Compared with the existing technology, the present invention improves the encapsulation efficiency and stability of curcumin by combining ethyl cellulose with curcumin liposomes. The present invention uses ethyl cellulose as the vesicle outer wall material of curcumin liposomes to synthesize curcumin liposome-ethyl cellulose composite particles. The present invention first uses amphiphilic vesicles to combine with curcumin to achieve the first encapsulation, and then uses ethyl cellulose to wrap the curcumin liposomes and the curcumin not encapsulated by the liposomes, thereby improving the structural stability of the liposomes and the overall encapsulation efficiency of curcumin. Curcumin remains highly stable under long-term room temperature storage and high-temperature heating conditions. Ethyl cellulose is combined with liposomes and free curcumin through non-covalent forces, and finally forms a macromolecular particle aggregate granule powder.

[0019] The present invention utilizes curcumin liposome-ethyl cellulose composite particles to prepare oil gels to enhance gel network stability and antioxidant capacity. The oil gel formed by pure ethyl cellulose only has a single gel network, so the oxygen in the gel can still migrate freely and generate toxic oxidation products with the oil. The composition and structure of the composite particles provided by the present invention can interact with the oil in the oil and thus enhance the overall stability of the gel network. The composite particles provided by the present invention help to enhance the solubility of the gel in the oil, exposing more hydroxyl groups to form a polymer interchain network and polymer-solvent interaction. The phospholipids in the composite particles also interact with the oil, and the three together form a tight gel network. In addition, according to the "associated colloid hypothesis" proposed in previous studies, curcumin aggregates in the reverse micelle region formed by the surfactant, where it combines with various free radicals produced by oil oxidation, thereby enhancing the efficiency of removing harmful oxidation products. Figure 10 The oil oxidation test of (A) shows that SL as a surfactant, the oil gel prepared by combining it with curcumin (CLEO), has a better long-term antioxidant effect than the oil gel with only curcumin added (ECOC). Figure 11 The tight binding of linseed oil and SL (Gt_SL) confirmed the existence of “reverse micelle region” in CLEO to enhance the antioxidant efficacy of curcumin.

[0020] The composite particles provided by this invention provide dual protection for curcumin against premature heat exposure. Ethyl cellulose undergoes molecular thermal motion at 145°C, forming a polymer chain network. The temperature rise is a quasi-linear process, and the composite particles provide dual protection for the vast majority of curcumin, preventing premature heat exposure before the system reaches the gelation temperature. This allows for greater retention of antioxidants, maintaining oxidative stability during subsequent storage and inhibiting the formation of oxidation products. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 This is a sample formation mechanism, preparation process and product demonstration provided according to an embodiment of the present invention.

[0023] Figure 2 The material forms provided according to the embodiments of the present invention are: pure EC powder (a), free curcumin (b), composite particles LE without curcumin (c), and CLE (d).

[0024] Figure 3 The average particle size, PDI, and zeta potential of Cur-Lip (A and B) provided by the embodiments of the present invention; the average particle size of CLE (C); and the curcumin encapsulation efficiency of Cur-Lip and CLE (D). Different lowercase letters within the same color column indicate significant differences. Different uppercase letters within the same color column indicate significant differences (p < 0.05).

[0025] Figure 4 FTIR infrared spectra (A), differential scanning calorimetry (B) and X-ray diffraction patterns (C) of free curcumin, EC, LE and CLE provided according to the embodiments of the present invention.

[0026] Figure 5 These are SEM images of EC (A), free curcumin (B), LE (C), and CLE (D) provided according to an embodiment of the present invention, magnified 5000 times.

[0027] Figure 6 The thermal stability of Curcumin, Cur-Lip, and CLE within 25°C to 95°C according to the examples of the present invention. * indicates significant difference (p<0.05).

[0028] Figure 7 The following table shows the storage stability of Curcumin, Cur-Lip, and CLE at 4°C (A) and 25°C (B) over 480 minutes according to examples of the present invention. The following table shows the storage stability of Cur-Lip and CLE at 4°C (C) and 25°C (D) over 40 days. * indicates significant difference (p < 0.05).

[0029] Figure 8 ATR-FTIR spectra of EC, ECOC, LEO and CLEO oil gels provided according to the embodiments of the present invention, with wavenumbers from 4000 to 500 cm -1 Spectrum (A), wave number 3700 to 3200 cm -1Spectrum of (B).

[0030] Figure 9 Figure 2 shows the strain scan (A), frequency scan (BD), continuous temperature scan (E), and crossover temperature (F, G'=G") of each group of oil gels provided according to the embodiments of the present invention. Different lowercase letters in the same color column indicate significant differences (p<0.05).

[0031] Figure 10 Figure 2 shows the p-Anisidine values (A) of the oil gels provided in the examples of the present invention at 21 and 28 days; and the clearance rates of ABTS+radical at different temperatures (B). Different lowercase letters within the same color column indicate significant differences. Different uppercase letters within the same color column indicate significant differences (p < 0.05).

[0032] Figure 11 are the binding free energy and energy components predicted by MM / GBSA (kcal / mol) according to the embodiments of the present invention. VDWAALS, EEL, EGB, ESURF, and DELTA TOTAL represent the van der Waals energy, electrostatic energy, electrostatic contribution to solvation, nonpolar contribution to solvation, and binding free energy, respectively. DETAILED DESCRIPTION

[0033] The following examples are provided to facilitate a clearer understanding of the present invention for those skilled in the art. It should be noted that the following examples do not limit the scope of the present invention and are provided for illustrative purposes only. Unless otherwise specified, the raw materials, reagents, and devices mentioned in the following examples are commercially available or obtained by known methods.

[0034] This invention proposes a novel solution. Utilizing liposome technology, soy lecithin (SL) is used to encapsulate the naturally active plant antioxidant curcumin, forming curcumin vesicles (Cur-Lip). Ethyl cellulose (EC) is then combined with these vesicles to form composite particles containing the natural antioxidant (Cur-Lip-EC, CLE). This material can capture curcumin that is not fully encapsulated by the liposome vesicles, thereby improving the curcumin encapsulation efficiency of CLE. Curcumin is susceptible to light and heat decomposition, while CLE has a strong ability to maintain curcumin's thermal and storage stability. Furthermore, the flaxseed oil oleogel prepared using CLE offers an additional barrier, delaying the thermal decomposition of curcumin. This allows for greater retention of antioxidants, helping to reduce lipid peroxides and lowering the oleogel's oxidation. Furthermore, the presence of SL enhances the gel's hardness and network, synergistically enhancing the antioxidant efficacy of curcumin. In conclusion, the oleogels prepared using CLE offer great potential for developing healthy and stable solid fat analogs that are rich in unsaturated fatty acids, low in saturated fatty acids, and zero in trans fatty acids.

[0035] The present invention aims to produce composite particles of curcumin liposomes combined with ethyl cellulose, and to use these particles for the preparation of linseed oil oleogels by heating. The composite particles provide a double layer of protection for the natural antioxidant, minimizing premature heat exposure of the curcumin, retaining more antioxidants, and reducing the degree of oxidation of the oleogel during long-term storage. Furthermore, the oleogel prepared using CLE is expected to exhibit enhanced mechanical and rheological properties, synergizing with the antioxidant effects of curcumin, resulting in a healthier and safer fat substitute. The method comprises the following steps:

[0036] 1. Synthesis of CLE

[0037] Figure 1 The synthesis mechanism, preparation process and product display of CLE are shown. Figure 1 The curcumin-loaded liposomes were prepared using the ethanol injection method. SL, cholesterol, and curcumin were dissolved in ethanol, stirred, and then injected into a pH buffer solution. Ethyl cellulose was added after stirring. The solvent was removed by rotary evaporation after stirring. The composite particles were then dried under vacuum to obtain the desired particles.

[0038] As a preferred embodiment, SL, cholesterol, and curcumin were dissolved in anhydrous ethanol at a ratio of 10:2:1 (w / w / w), stirred at room temperature for 30 minutes, and then injected into phosphate buffered saline (PBS) at pH 7.2 using a disposable syringe at a rate of one drop per second. The mixture was stirred at 600 rpm and 25°C for 30 minutes. After stirring, the solution was stirred on a magnetic stirrer at 700 rpm, and constant amounts of EC powder were gradually added. When the ethanol concentration was fixed at 30%, the SL to EC ratio was 9%, 10%, 12%, and 13% by weight. When the SL to EC ratio was fixed at 13% by weight, four ethanol concentration gradients were used: 30%, 35%, 40%, and 45% (EtOH / PBS, v / v). After 120 minutes of stirring, the mixture was transferred to a distillation flask and evaporated on a rotary evaporator at 140 rpm and 40°C until no excess water remained. The CLE was transferred to a glass dish and dried under vacuum at room temperature for 48 hours before testing. FTIR, SEM, XRD, DSC, and molecular dynamics simulation data of CLE showed that CLE was successfully synthesized. Figure 2 Comparisons of pure EC powder (a), free curcumin (b), composite particles LE without curcumin (c), and CLE (d) are shown.

[0039] Figure 3 The average particle size, PDI and Zeta potential of Cur-Lip (A and B); the average particle size of CLE (C); and the curcumin encapsulation efficiency of Cur-Lip and CLE (D) are shown. Different lowercase letters on the same color column indicate significant differences. Different uppercase letters on the same color column indicate significant differences (p<0.05). Figure 3 In A and 3C, the particle size of Cur-Lip is smaller than that of CLE, and the particle size of CLE increases with the increase of SL concentration and ethanol concentration. Figure 3 Regardless of the changes in the concentrations of SL and EtOH in B, the zeta potential of Cur-Lip changes relatively steadily, ranging from -20mV to -25mV. A higher negative zeta potential usually means that the formulation is more stable and less likely to aggregate. In summary, Figure 3 The effects of different ethanol and SL concentrations on the particle size, zeta potential, and encapsulation efficiency of Cur-Lip and CLE formulations were compared. This provided insights into the stability, particle size, and encapsulation efficacy of the formulations under different experimental conditions.

[0040] 2. Preparation of CLE Oil Gel

[0041] Figure 1 The preparation process and product display of CLE oil gel are also shown. Figure 1As shown, CLE composite particles are mixed with linseed oil to form a uniform dispersion, and the dispersion is placed in a closed reaction vessel and heated to a target temperature higher than the glass transition temperature of ethyl cellulose and then cooled. The heating environment is dry and oxygen-free.

[0042] As a preferred approach, the CLE composite particles were mixed with α-linolenic acid-rich linseed oil in a three-necked flask to prepare an oleogel. The method is as follows: Before heating, the mixture was stirred at 150 rpm at room temperature for 10 minutes to uniformly mix the powder and oil. The three-necked flask was immersed in dimethyl silicone oil preheated to 140°C and the mixture was stirred at 250 rpm, while the temperature was continuously monitored. When the system was heated to 145°C, slightly above the glass transition temperature of EC, it was maintained at this temperature for 10 minutes to ensure uniform heating. Heating was performed at 35°C under dry nitrogen at a flow rate of 10 mL / min to remove water vapor and oxygen generated by the heating, ensuring an oxygen-free heating environment. Upon completion of heating, the sample was immediately transferred to a heat-resistant plastic bottle. The sample was stored at 25°C for 4 hours and then transferred to 4°C for 24 hours before further analysis.

[0043] As a comparative example, oleogels were prepared by mixing 7.5 wt% (w / w, EC / linseed oil) of EC, LE containing a constant EC ratio (composite particles without curcumin), and flaxseed oil enriched in α-linolenic acid in a three-necked flask. The prepared products were used for the next analysis.

[0044] 3. CLE Curcumin Encapsulation Efficiency Test

[0045] CLE was added to PBS (pH 7.2) and shaken using a vortexer. The composite microparticles were then dispersed by waterbath sonication for 30 minutes to separate unencapsulated Cur-Lip and free curcumin from the CLE. The supernatant was extracted by centrifugation at 8500×g for 30 minutes at 4°C. The supernatant was then transferred to a filtration apparatus, rinsed with PBS, and filtered. The filtrate was collected and combined with the supernatant, which was then centrifuged at 15000×g for 30 minutes at 4°C. The precipitate was removed and diluted to 2 mL with anhydrous ethanol (EtOH). The CLE was mixed with a mixed organic solvent (chloroform:ethanol = 8:2, v / v) and sonicated for 15 minutes to fully extract the curcumin from the CLE. A 2 mL portion of the curcumin organic solution was filtered three times, and the filtrate was collected. 0.5 mL of the filtrate was dissolved in anhydrous ethanol. The free curcumin content was determined using a UV spectrophotometer at a wavelength characteristic for curcumin, 425 nm. The curcumin content was calculated based on the established curcumin standard curve. The encapsulation efficiency of Cur-Lip was used to express the curcumin content, as calculated by the following formula:

[0046] Encapsulation efficiency (%) = [(C0-C u ) / C0]×100

[0047] Where C0 is the total amount of initial curcumin in CLE, C u It is unencapsulated curcumin in PBS.

[0048] The mass ratio of SL to EC and the ethanol concentration in the solution system affect the encapsulation efficiency of curcumin in CLE. Increasing the SL ratio in CLE requires increasing the ethanol concentration to allow EC to bind more curcumin liposomes and free curcumin. The optimal curcumin encapsulation efficiency was achieved in the composite particles with 12% wt EC and 40% EtOH-CLE.

[0049] 4. Fourier transform infrared spectroscopy (FTIR) and SEM scanning electron microscopy test:

[0050] Figure 4 FTIR infrared spectra (A), differential scanning calorimetry (B) and X-ray diffraction patterns (C) of free curcumin, EC, LE and CLE provided according to the embodiments of the present invention. Figure 5 These are SEM images of EC (A), free curcumin (B), LE (C), and CLE (D) provided according to an embodiment of the present invention, magnified 5000 times.

[0051] The sample slices were prepared using KBr. The samples were ground and sieved before preparation and dried using an infrared drying lamp for 2 minutes before testing. Fourier transform infrared spectrometer was used at 500-4000 cm -1 Scan the sample within the range of 4cm –1 The resolution of the scan was 64 times per cycle, and a total of 8 cycles were performed. It was found that the COC band of the characteristic group belonging to EC in CLE shifted toward lower wavenumbers. This was attributed to the binding of the hydroxyl group of EC to the C=O of SL. EC and curcumin liposomes interacted through non-covalent forces. Molecular dynamics simulations showed that there were van der Waals forces and hydrogen bonds between them.

[0052] Sample morphology was analyzed using scanning electron microscopy. Prior to testing, samples were stored in a vacuum oven to minimize oxygen and moisture interference. Following the principle of SEM secondary electron detection, samples were subjected to a standardized gold spraying procedure to complete the metallization process prior to scanning. Samples coated with conductive adhesive were gold sprayed for 1 minute using a vacuum sample preparation apparatus. SEM images at 5000x magnification revealed that the CLE particle aggregates had increased in size. Compared to EC, the surface had a denser and more numerous distribution of small pores, including some semicircular pores with diameters greater than 1 μm. These pores were likely formed by solvent evaporation under reduced pressure. Smooth particles were present within and around some of the pores, revealing a liposome-like morphology and measuring several hundred nanometers in size. These pores, varying in size, provide sufficient binding sites for both the liposomes and curcumin, enhancing their stability.

[0053] To determine the thermodynamic changes in the composite particles, differential scanning calorimetry (DSC) was used to obtain thermodynamic information for the samples (EC, curcumin, LE, and CLE). The samples were sealed in heated cells and heated at a scan rate of 10°C / min from 20 to 250°C under a flow rate of 20 mL / min of dry nitrogen. A blank sealed cell was heated using the same procedure to obtain a baseline.

[0054] XRD diffraction patterns showed that the combination of curcumin or curcumin liposomes with EC did not change the amorphous small crystalline structure of EC.

[0055] 5. Curcumin stability test

[0056] Figure 6 The thermal stability of Curcumin, Cur-Lip, and CLE within 25°C to 95°C according to the examples of the present invention. * indicates significant difference (p<0.05).

[0057] Thermal stability testing: The absorbance of curcumin in samples treated at 25-95°C was recorded in increments of 10°C. Before each measurement, the samples were kept at a constant temperature in a constant-temperature water bath for 15 minutes. The heated CLE was then processed according to the encapsulation efficiency measurement method described above. Consistent with the results for the CLE with the optimal encapsulation efficiency, CLE treated with a high SL to EC mass ratio and a high ethanol concentration exhibited enhanced curcumin thermal stability.

[0058] Figure 7 The following table shows the storage stability of Curcumin, Cur-Lip, and CLE at 4°C (A) and 25°C (B) over 480 minutes according to examples of the present invention. The following table shows the storage stability of Cur-Lip and CLE at 4°C (C) and 25°C (D) over 40 days. * indicates significant difference (p < 0.05).

[0059] Storage stability testing: CLE was stored at 4°C and 25°C for 40 days to investigate the long-term stability fluctuations of curcumin at different temperatures. The maximum absorbance at the characteristic wavelength of curcumin was recorded at 0, 1, 3, 5, 7, 20, and 40 days. Consistent with the thermal stability results, CLE treated with a high SL to EC mass ratio and a high ethanol concentration exhibited enhanced long-term storage stability of curcumin.

[0060] 6. Oil binding capacity test:

[0061] The oil binding capacity test demonstrates the ability of the oleogel network to capture liquid oil. A 1.5 g sample was melted and transferred to a 2 mL EP tube. The sample was stored at 4°C for 2 hours and weighed. Following the OBC centrifugation method, the stored sample was centrifuged at 7500 × g for 40 minutes at 4°C. After centrifugation, the EP tube was inverted on filter paper for 1 hour to remove the liquid oil and reweigh the sample. The following formula was used for calculation:

[0062] Oil binding capacity (%) = (D1 / D0) × 100

[0063] Where D1 and D0 represent the mass of the EP tube after centrifugation to remove liquid oil and the mass of the EP tube before centrifugation, respectively.

[0064] Compared with the oil gel without SL addition, the oil binding capacity of the oil gel prepared by CLE was improved by 11.07%, indicating that SL can cooperate with the EC polymer network to enhance the oil capture ability of the oil gel and improve the robustness of the gel network.

[0065] 7. Hardness and rheology test

[0066] The hardness of the oleogels was measured using a texture analyzer. The sample was placed on a 5 kg sample load cell and compression tested using a 5 mm cylindrical probe, penetrating 10 mm from the sample surface at a constant speed of 1 mm / s at 25°C. The maximum positive force represents the final hardness of the sample, expressed in g. The results showed that the oleogels prepared with CLE had the strongest hardness compared to the oleogels without SL, indicating a more robust oleogels network.

[0067] The rheological properties of the samples were measured using an advanced rotational rheometer with a 1000 μm gap and 40 mm diameter parallel aluminum plates, including stress sweeps, frequency sweeps, and continuous temperature sweeps. To ensure a constant test temperature, the sample was covered with hydrazine during the analysis. The results are shown in Figure 2. Figure 9As shown, the results show that the presence of SL improves the rheological properties of the oleogel. The storage modulus of the oleogel with SL is greater than that of the oleogel without SL, both in strain and frequency sweeps. This indicates that SL enhances the gel strength of the EC oleogel and forms a more stable gel network. Temperatures exceeding the crossover temperature (storage modulus = loss modulus) of the continuous temperature sweep indicate that the gel transitions from a solid-like to a liquid-like state. The crossover temperature of the CLE oleogel is higher than that of the oleogel containing only SL, suggesting that curcumin may weaken the gel plasticizing effect of SL, reducing the fluidity between polymer chains and causing a shift in the crossover temperature. Table 1 shows the oil binding capacity and hardness of linseed oil oleogels with different components (with or without SL or curcumin). *Different lowercase letters indicate significant differences in oil binding capacity between oleogels with the same gelling agent. Different uppercase letters indicate significant differences in hardness between oleogels with the same gelling agent (p < 0.05).

[0068] Table 1. Oil binding capacity and hardness of linseed oil gels with different components (whether SL or curcumin was added)

[0069]

[0070]

[0071] 8. Test of oil gel oxidation degree

[0072] p-Anisidine Value (p-Anisidine) Test: The p-Anisidine value (pAV) is used to measure the oxidative stability of the oleogel after 21 and 28 days of storage at 25°C. The pAV reflects the production of secondary oxidation products during long-term storage and is a suitable indicator of the degree of oxidation in EC Oleogel. This value is measured according to the method specified in the Chinese National Standard "Determination of Anisidine Value of Animal and Vegetable Oils and Fats" (GB / T 24304-2009 / ISO 6885:2006). Briefly, the oleogel was melted before testing and dehydrated using anhydrous sodium sulfate. The sample was then dissolved in 25 mL of isooctane. 5 mL of the sample-containing isooctane solution was placed in a test tube, and 1 mL of p-Anisidine reagent (0.25%, w / v, in 100 mL of >99.9% glacial acetic acid) was added. The mixture was thoroughly mixed and allowed to react in the dark for 8 minutes. The absorbance of the reaction solution (A1), the absorbance of the unreacted test solution (A0, glacial acetic acid + isooctane sample solution), and the absorbance of the blank solution (A2, isooctane + 1 mL p-Anisidine reagent) were measured at 350 nm using a UV spectrophotometer within 2 minutes. All measurements were repeated three times, and the pAV was calculated using the following formula:

[0073] pAV=25*[1.2*(A1-A2-A0)] / m

[0074] m represents the weight of the oil gel in grams (g)

[0075] Total antioxidant capacity test: The total antioxidant capacity of lipophilic substances is tested using the ABTS method. The production and application of oil gels require heat treatment, so the oil gel is heated at 185°C for 5 minutes to simulate a home cooking environment. The total antioxidant capacity of the oil gel after preparation and after secondary heating is tested using a commercial ABTS kit, which indirectly reflects the content of antioxidant substances in the oil gel. In short, ABTS generates a stable blue-green cationic free radical ABTS after oxidation. ·+ The substance has a maximum absorption at 734 nm, and the solution of the substance is used as the working solution control (L w 50 μL of sample extract was added to 950 μL of working solution (L t ) Mix thoroughly, the antioxidants in the sample extract react with the free radicals, and the absorbance at 734 nm is measured within 10 minutes. ·+ The clearance rate was calculated using the following formula:

[0076] Clearance rate of ABTS ·+ (%)=[(L w -L t )] / L w *100

[0077] L w Represents the absorbance of the control working solution, L t Represents the absorbance of the reaction solution.

[0078] Figure 10 Figure 2 shows the p-Anisidine values (A) of the oil gels provided in the examples of the present invention at 21 and 28 days; and the clearance rates of ABTS+radical at different temperatures (B). Different lowercase letters within the same color column indicate significant differences. Different uppercase letters within the same color column indicate significant differences (p < 0.05).

[0079] Compared with the oleogel with only curcumin added, the oxidation degree of CLE oleogel is lower. SL exists in the oleogel as a surfactant. According to the association colloids hypothesis, surfactant compounds can produce oil-in-water nanoparticles or microemulsions with reverse micelles or lamellar structures in LO. Lipid peroxides (ROOH) produced during lipid peroxidation are surface active and tend to be located in the reverse micelle interface region. Curcumin, as a polar antioxidant, also tends to accumulate in the reverse micelle interface region. The contact between the two in the reverse micelle interface region is conducive to the removal of oxidation products. Therefore, this effect effectively delays the oxidation process of CLEO. In addition, because CLE provides a double-layer protective barrier for curcumin, the heating time of curcumin is delayed during the gel preparation process, thereby retaining more active antioxidants, which contributes to reducing the thermal oxidation of Oleogel. Compared with EC oleogel, ABTS oleogel with SL added ·+ The higher radical clearance rate is attributed to the reverse micelle structure formed by SL, which captures transition metals, a pro-oxidant, and slows the oxidation rate of the gel. Overall, CLE oil gel has the lowest degree of oxidation, which is attributed to its more compact gel network and the presence of curcumin as an antioxidant.

[0080] 9. Molecular dynamics simulation (MD simulation)

[0081] Figure 11 are the binding free energy and energy components predicted by MM / GBSA (kcal / mol) according to the embodiments of the present invention. VDWAALS, EEL, EGB, ESURF, and DELTA TOTAL represent the van der Waals energy, electrostatic energy, electrostatic contribution to solvation, nonpolar contribution to solvation, and binding free energy, respectively.

[0082] Glycerol trilinolenate (Gt), the fatty acid with the highest content in linseed oil, was selected as the representative substance of liquid oil. Molecular dynamics simulation was used to analyze the following five molecular binding systems: EC_Cur (EC and curcumin), EC_Gt (EC and liquid oil), EC_SL (EC and SL), Gt_SL (liquid oil and SL), Gt_Cur (liquid oil and curcumin), including the system binding energy and the type of non-covalent interaction between the systems. The results showed that the binding energy of all systems was negative, indicating that it was conducive to the formation of the complex, and the main contribution to the binding energy was the van der Waals force. The binding energy of Gt_SL (-26.27 kcal / mol) and EC_Gt (-26.46 kcal / mol) was the largest, indicating that the addition of 1% SL promoted the solubility of EC in oil and exposed more terminal hydroxyl groups of EC, but did not affect the polymer-polymer interaction in the oil gel, that is, the hydrogen bond between EC chains. Figure 8 The results of infrared spectra also confirm this. Figure 8 (B) Displayed from 3700cm -1 -3200cm -1 Compared with the characteristic absorption curve of liquid linseed oil in group a, the other groups of oil gels have a wavelength of 3464cm -1 or 3462cm -1 Characteristic absorption peaks appear at . These two characteristic absorption peaks indicate the formation of hydrogen bonds between EC molecules. Notably, the presence of SL in the oil gel does not affect the intermolecular hydrogen bonding between EC molecules, which is one of the keys to gel network formation. Instead, the binding of oil to SL synergizes the binding of EC to oil and EC to EC, and these three interactions together form a more robust gel network. In addition to van der Waals binding energy, electrostatic forces also participate in the molecular bonding between EC_SL and EC_Cur. Hydrogen bonds are electrostatic forces, thus echoing the FTIR results of CLE. The results show that Gt_Cur has the weakest binding energy, indicating that curcumin dissolution in oil does not weaken the gel network. Instead, the presence of the network inhibits curcumin crystal growth, reduces the sedimentation rate of curcumin in oil, and thus enhances its antioxidant potency. The formation of EC_Cur also helps capture curcumin, reducing its crystal formation and precipitation.

[0083] In summary, this invention, for the first time, utilizes a gelling agent combined with liposomes to form antioxidant-containing macromolecular composite particle aggregates, providing dual protection for curcumin, which is susceptible to environmental factors. This invention explores the multiple uses of EC beyond direct oil gel formation. Compared to standalone curcumin liposomes, the composite particles significantly improve the curcumin encapsulation efficiency, approaching 100%. Furthermore, the composite particles exhibit excellent thermal and storage stability, resisting the premature and substantial inactivation of curcumin caused by the gradual increase in temperature during gel preparation, and improving the oxidative stability of the gel during subsequent high-temperature continuous heating and long-term storage.

[0084] The oleogel formed from composite particles in this patented invention possesses a tight gel network. Soy lecithin interacts with the oil in the gel and increases the solubility of ethyl cellulose in the oil, exposing more hydroxyl groups. These hydroxyl groups spontaneously form polymer-polymer and polymer-oil interactions, which together enhance the gel network stability. Furthermore, the addition of lecithin enhances the antioxidant efficacy of curcumin and increases the hardness and elastic modulus of the oleogel. In summary, CLE oleogel possesses a tight gel network and excellent antioxidant capacity.

[0085] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A composite particle containing an antioxidant, characterized in that The composite particles comprise curcumin liposomes formed by encapsulating curcumin in ethyl cellulose and lecithin, wherein the ethyl cellulose interacts with the curcumin liposomes through non-covalent forces, and the porous structure of the ethyl cellulose provides binding sites for the curcumin liposomes.

2. An antioxidant-containing oil gel, characterized in that The composite particles according to claim 1 are dispersed in linseed oil to form a gel network, wherein the gel network comprises hydrogen bonding between ethyl cellulose polymers and van der Waals bonding between linseed oil, lecithin and ethyl cellulose.

3. A method for preparing composite particles containing antioxidants, characterized in that: include: Lecithin, cholesterol, and curcumin were mixed and dissolved in ethanol, stirred, and then injected into pH buffer solution; After stirring, add ethyl cellulose; After stirring, the solvent was removed by rotary evaporation; The composite particles were obtained by vacuum drying.

4. The preparation method according to claim 3, characterized in that The volume concentration of ethanol in the control system is 30%-45% (v / v), and the weight ratio of lecithin to ethyl cellulose is 9%-13%.

5. The preparation method according to claim 3, characterized in that The volume concentration of ethanol in the control system was 40% (v / v), and the weight ratio of lecithin to ethyl cellulose was 12%.

6. The preparation method according to claim 3, characterized in that The pH buffer is a phosphate buffer with a pH of 7.

2.

7. The preparation method according to claim 3, characterized in that Lecithin, cholesterol, and curcumin were mixed and dissolved in ethanol, and after stirring, pH buffer solution was injected at a rate of 1 drop per second, and stirred at 25° C. and 600 rpm for 30 minutes.

8. The preparation method according to claim 3, characterized in that The lecithin is soybean lecithin. Soybean lecithin, cholesterol and curcumin are mixed in a weight ratio of 10:2:1, dissolved in anhydrous ethanol, and stirred at room temperature for 30 minutes.

9. A method for preparing an antioxidant-containing oil gel, characterized in that: include: The composite particles according to claim 1 are mixed with linseed oil to form a uniform dispersion, and the dispersion is placed in a sealed reaction container and heated to a target temperature higher than the glass transition temperature of ethyl cellulose and then cooled, wherein the heating environment is dry and oxygen-free.

10. The preparation method according to claim 9, characterized in that Heating is performed using a high boiling point silicone heat transfer medium.

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