A resveratrol-loaded multi-component oil gel and a preparation method thereof

Abstract

The present application relates to the technical field of oil gel preparation, and discloses a multi-component oil gel loaded with resveratrol and a preparation method thereof, which comprises an oil gel made of base oil, a gelling agent, resveratrol and a surfactant; during preparation, the base oil, the gelling agent and the resveratrol are heated and mixed until homogeneous; the temperature is lowered and the light transmittance is monitored, and the surfactant is added at the phase transition critical point; when the torque step rises, the stirring speed and the cooling rate are lowered for solidification, and then the oil gel is left to stand and mature. The surfactant is attached to the interface of the precipitated gel network and combined with resveratrol, so that the distribution state of resveratrol is changed to inhibit the crystallization and precipitation of resveratrol; the light transmittance and torque monitoring are combined to control the micro network forming process and eliminate residual internal stress, so that the loading capacity of the oil gel for resveratrol, the uniformity of the network structure and the long-term physical stability are improved.

Description

Technical Field

[0001] This invention relates to the field of oleogel preparation technology, specifically to a multi-component oleogel loaded with resveratrol and its preparation method. Background Technology

[0002] Resveratrol is a polyphenol with applications in food and medicine. However, its low solubility in water and common oils limits its practical applications. Oil gels, on the other hand, are systems with a spatial network structure formed by structuring liquid oils with gelling agents. They are often used to encapsulate and deliver poorly soluble active ingredients.

[0003] Existing oleogel systems struggle to balance high resveratrol loading with long-term stability. Resveratrol readily self-aggregates in conventional lipid systems, leading to crystallization during oleogel cooling and storage. Furthermore, conventional oleogel preparation processes often involve mixing and melting components, followed by direct cooling. This approach lacks control over microscopic phase transitions such as gelling agent precipitation, nucleation, and network backbone crosslinking. During continuous cooling, component distribution and backbone growth rates are difficult to coordinate, easily resulting in an uneven internal network structure within the gel. Simultaneously, simple cooling and stirring can introduce and retain internal stresses in the solidified gel network. With prolonged storage, oleogels with internal stress are prone to macroscopic physical instabilities such as backbone shrinkage, free oil seepage, or phase separation, further leading to the shedding of encapsulated active materials and reducing the actual encapsulation rate and performance of the system. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a multi-component oleogel loaded with resveratrol and its preparation method, which solves the problems of low solubility and easy crystallization of resveratrol in conventional lipid systems, and the lack of precise control over the microscopic phase transition process in existing oleogel preparation processes, resulting in uneven network structure, low encapsulation rate of active substances, and poor macroscopic stability of the system.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a multi-component oleogel loaded with resveratrol and its preparation method, comprising:

[0006] In a first aspect, the present invention provides a multi-component oleogel loaded with resveratrol, employing the following technical solution:

[0007] A multi-component oleogel loaded with resveratrol is made from the following raw materials in the indicated mass percentages: 78.0%-89.7% matrix oil, 10.0%-20.0% gelling agent, 0.1%-1.0% resveratrol, and 0.2%-1.0% surfactant; the matrix oil is soybean oil or peanut oil; the gelling agent is carnauba wax, ethyl cellulose, or a composite material composed of β-sitosterol and lecithin; the surfactant is Span 60; the multi-component oleogel has a network structure formed by stress-releasing curing, the gelling agent undergoes phase separation in the matrix oil to form a microcrystalline network or polymer network; the surfactant adheres to the interface of the microcrystalline network or polymer network and binds resveratrol.

[0008] By employing the above technical solution, a multi-component system is constructed using base oil, gelling agent, surfactant, and resveratrol, thus achieving the effect of increasing the resveratrol loading while maintaining the physical stability of the system. The microscopic mechanism is as follows: As the system temperature decreases, the solubility of the gelling agent in the base oil decreases, leading to phase separation and the formation of a microcrystalline network or polymer network framework. Span 60, as a nonionic surfactant, aggregates at the interface between the gel network and the free oil phase due to its amphiphilic structure. The hydrophilic groups of Span 60 form hydrogen bonds with resveratrol molecules, binding resveratrol to the microscopic network interface, altering the thermodynamic distribution of resveratrol in the free oil phase, and inhibiting the aggregation and crystallization of resveratrol molecules.

[0009] Preferably, when the gelling agent is a composite material composed of β-sitosterol and lecithin, the mass ratio of β-sitosterol to lecithin is 4:1.

[0010] By adopting the above technical solution, β-sitosterol and lecithin undergo co-crystallization at a mass ratio of 4:1, which promotes the formation of tubular or layered liquid crystal networks in the system, increases the mechanical strength of the gel skeleton, and enhances the retention capacity of resveratrol.

[0011] Preferably, it is made from the following raw materials in weight percentages: 89.7% soybean oil, 10.0% carnauba wax, 0.1% resveratrol and 0.2% Span 60.

[0012] By adopting the above technical solution, the ratio of soybean oil to carnauba wax is controlled, and the number of precipitated crystal nuclei and the distribution of network pore size are adjusted to meet the loading requirements of resveratrol at the corresponding concentration.

[0013] Preferably, it is made from the following raw materials in weight percentages: 82.9% soybean oil, 16.0% composite material composed of β-sitosterol and lecithin, 0.5% resveratrol, and 0.6% Span 60.

[0014] By adopting the above technical solution, the total concentration of gelling agent and surfactant concentration are increased, and the interfacial binding sites are increased to meet the loading requirements of resveratrol at the corresponding concentration.

[0015] Secondly, the present invention provides a method for preparing a multi-component oleogel loaded with resveratrol, using the following technical solution:

[0016] A method for preparing a multi-component oleogel loaded with resveratrol includes the following steps:

[0017] Add the base oil, gelling agent and resveratrol into a sealed reactor according to the set mass percentage, remove the air and fill with high-purity nitrogen to a slight positive pressure, start the variable frequency stirrer to perform high shear stirring, and heat the system to make it reach a thermodynamic homogeneous dispersion state.

[0018] During this period, the surfactant is heated and melted separately for later use;

[0019] When switching cooling media, the system is forced to cool down at the first cooling rate. During the cooling process, high shear stirring is maintained, and the transmittance of the material in the reactor is continuously monitored by an online transmittance sensor.

[0020] When the transmittance measurement value suddenly drops from the initial homogeneous state and reaches the critical point of phase transition, the liquid surfactant is added dropwise into the closed reaction vessel at a uniform rate, so that the surfactant adheres to the interface of the precipitated microcrystalline network or polymer network.

[0021] After the surfactant is added, monitor the torque feedback value of the stirring spindle motor. When the torque feedback value shows a step increase, immediately reduce the stirring speed to enter a weak shear state, and at the same time reduce the cooling rate to the second cooling rate to cool the material to the preset low temperature for initial solidification.

[0022] The partially cured product is removed and transferred to a constant temperature environment for static curing to eliminate internal stress, thus obtaining a multi-component oleogel.

[0023] By employing the above technical solution, the gel formation process is controlled through transmittance and torque monitoring, thereby improving structural uniformity. The preparation mechanism is as follows:

[0024] Dispersion stage: Under nitrogen protection, mechanical shearing and heating are used to mix the components to achieve a homogeneous state.

[0025] Precipitation and Binding Stage: During cooling, a sudden drop in transmittance indicates that the system has reached the critical point of phase transition, and the gelling agent begins to aggregate and precipitate. At this time, a liquid surfactant is added to adhere to the interface of the precipitated network, preventing the surfactant from binding with resveratrol prematurely.

[0026] Crosslinking and curing stage: The step increase in torque indicates that macroscopic crosslinking has begun in the micro-network, and the system generates yield stress. At this point, reducing the stirring speed and cooling rate reduces the damage of strong shear to the network skeleton, allowing the gel network to further crosslink and cure.

[0027] Curing stage: The process involves keeping the gel at a constant temperature to promote the rearrangement of molecular or crystal structures, eliminate internal stress caused by cooling and shearing, and prevent phase separation of the gel during storage.

[0028] Preferably, the pressure range for introducing high-purity nitrogen to a slightly positive pressure is 0.05MPa-0.15MPa; the target temperature for heating the system is 70℃-170℃; the high-shear stirring speed is 300rpm-500rpm; and the constant temperature is maintained for 20min-30min.

[0029] By adopting the above technical solution, a slight positive pressure is used to block oxygen and prevent the oxidation of the oil matrix and resveratrol; the corresponding temperature and stirring parameters allow the gelling agent to melt and mix with the matrix oil.

[0030] Preferably, the temperature at which the surfactant is heated and melted separately for later use is 60℃-65℃; the first cooling rate is 1.0℃ / min-2.0℃ / min.

[0031] By adopting the above technical solution, the surfactant is controlled to be in a liquid state, thereby increasing its dispersion rate during dropwise addition; the setting of the first cooling rate controls the nucleation and precipitation process of the gelling agent.

[0032] Preferably, reaching the phase transition critical point means that the transmittance measurement value drops suddenly by 10%-20% compared with the initial homogeneous state; the dropping time for adding the liquid surfactant to the closed reaction vessel at a uniform rate is 2min-5min.

[0033] By adopting the above technical solution, the timing of adding surfactant is determined by the amplitude of the change in transmittance; the adding time is controlled to match the precipitation rate of the network, so that the surfactant is distributed at the network interface.

[0034] Preferably, the stirring speed after entering the weak shear state is 30 rpm-80 rpm; the second cooling rate is 0.3℃ / min-0.8℃ / min.

[0035] By adopting the above technical solutions, the shear force and cooling rate are reduced, providing stable hydrodynamic and thermodynamic conditions for the crosslinking of the network skeleton.

[0036] Preferably, the preset low temperature is 2℃-6℃, and the initial curing time is 18h-30h; the constant temperature environment is 20℃-30℃, and the static curing time is 2d-4d.

[0037] By adopting the above technical solution, low-temperature curing promotes further precipitation of the gelling agent and increases network density; room-temperature curing allows the system to reach thermodynamic equilibrium.

[0038] This invention provides a multi-component oleogel loaded with resveratrol and its preparation method. It has the following beneficial effects:

[0039] 1. This invention introduces a surfactant into a multi-component system. Utilizing the adhesion of the surfactant to the gel network interface during gelation, the hydrophilic groups of the surfactant form hydrogen bonds with resveratrol. This structural feature alters the distribution of resveratrol in the free oil phase, blocking the self-aggregation pathway of resveratrol molecules, thereby inhibiting the crystallization and precipitation of resveratrol and increasing the resveratrol loading capacity of the oil gel system.

[0040] 2. The preparation method of this invention achieves stage control of the microscopic phase transition process through online transmittance and motor torque monitoring. The surfactant is added dropwise at the critical point of phase transition indicated by a sudden drop in transmittance, preventing the surfactant from prematurely encapsulating resveratrol to form free micelles during the homogeneous phase. The stirring speed and cooling rate are promptly reduced when the torque increases stepwise, avoiding the physical damage to the macroscopic cross-linked network caused by continuous high shear force, thereby improving the uniformity of the internal structure of the multi-component oleogel.

[0041] 3. This invention employs a two-stage temperature control post-processing method after the material network skeleton has cross-linked. First, a preset low-temperature environment promotes further precipitation of soluble components to increase the density of the gel network. Then, it is transferred to a room-temperature environment for static curing, which promotes the rearrangement of internal crystals or polymer chains and eliminates residual internal stress caused by forced cooling and mechanical shearing. This process brings the gel system to thermodynamic equilibrium, reducing the risk of phase separation and release of the oleogel during long-term storage. Attached Figure Description

[0042] Figure 1 This is a phase change kinetic response curve during the cooling and curing process of Embodiment 2 of the present invention;

[0043] Figure 2 This is a superimposed Fourier transform infrared spectrum of resveratrol and oleogel sample from Example 2 of the present invention. Detailed Implementation

[0044] 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.

[0045] Examples 1-3:

[0046] Example 1: This example provides a method for preparing a multi-component oleogel loaded with resveratrol, using a low molecular weight single-component gelling agent (carnauba wax CWO) system, including the following steps:

[0047] (Note: The soybean oil and peanut oil used in this embodiment and subsequent embodiments are industrial-grade conventional base oils; carnauba wax, β-sitosterol, lecithin, ethyl cellulose, resveratrol, and surfactant Span 60 are all commercially available conventional products. The entire process is carried out in a closed reactor equipped with a jacketed temperature control, variable frequency stirring, online transmittance sensor, and motor torque monitoring system.)

[0048] Step 1: Add 89.7% soybean oil, 10.0% carnauba wax and 0.1% resveratrol to the reactor by weight percentage.

[0049] Seal the reactor, turn on the vacuum pump to remove air from the reactor, and purge with high-purity nitrogen to a slightly positive pressure of 0.05 MPa to provide an oxygen-free and antioxidant environment. Turn on the reactor jacket heating to raise the system temperature to 85°C (ensuring that the carnauba wax is completely melted).

[0050] Turn on the variable frequency stirrer, set the speed to 300 rpm for high-shear stirring, and maintain the constant temperature for 20 minutes to achieve thermodynamic homogeneous dispersion of the material.

[0051] Meanwhile, 0.2% of Span 60 is heated to 60°C and melted into a low-viscosity liquid in a separate heated temporary storage tank for later use.

[0052] Step 2: Switch the cooling medium in the reactor jacket to cool the system at a forced cooling rate of 1.0℃ / min.

[0053] During the cooling process, a high shear speed of 300 rpm is maintained, and the material status inside the reactor is continuously monitored using an online transmittance sensor.

[0054] Step 3: When the transmittance measured in the reactor drops by 10% from the initial homogeneous state (i.e., the system is judged to have reached the phase transition critical point for the precipitation of the microcrystalline network), immediately start the high-pressure metering pump and add the preheated liquid Span 60 to the reactor at a constant flow rate through the heating pipeline within 2 minutes, so that it adheres to the microcrystalline network interface and combines with resveratrol.

[0055] Step 4: After the Span 60 drops are added, the torque feedback value of the stirring spindle motor is monitored in real time through the system.

[0056] When the torque feedback value is detected to increase in a stepwise manner, the stirring speed is immediately reduced from 300 rpm to 30 rpm in a weak shear state via the frequency converter.

[0057] Simultaneously, the flow rate of the cooling medium was adjusted to reduce the cooling rate to 0.3℃ / min. After the material was cooled to 6℃, it was kept in place for 18 hours for initial solidification.

[0058] Step 5: Remove the pre-cured oleogel from the reactor and transfer it to a constant temperature environment of 20°C for 2 days to release internal stress and obtain a multi-component oleogel product.

[0059] Example 2: This example provides a method for preparing a multi-component oleogel loaded with resveratrol. The method utilizes a low molecular weight multi-component gelling agent system (β-sitosterol / lecithin S / LO) and includes the following steps:

[0060] Step 1: Add 82.9% soybean oil, 16.0% gelling agent (with a mass ratio of β-sitosterol to lecithin of 4:1) and 0.5% resveratrol to the reactor by mass percentage.

[0061] The reaction vessel was sealed, purged under vacuum, and then filled with high-purity nitrogen to a slightly positive pressure of 0.10 MPa.

[0062] Turn on the jacket heating to raise the system temperature to 70°C. Turn on the variable frequency stirrer and set the speed to 400 rpm, then maintain the temperature for 25 minutes.

[0063] Meanwhile, 0.6% of Span 60 is separately heated to 60°C in a temporary storage tank for later use.

[0064] Step 2: Switch the jacket cooling medium to force subcool the system at a rate of 1.5℃ / min.

[0065] During the cooling process, a high shear speed of 400 rpm was maintained, and the speed was continuously monitored by an online transmittance sensor.

[0066] Step 3: When the transmittance measured in the reactor suddenly drops by 15% to reach the critical point of phase change, start the metering pump and add liquid Span 60 to the reactor at a constant flow rate through the heating pipeline within 3 minutes.

[0067] Step 4: Continuously monitor the torque of the stirring spindle motor. When the torque feedback value shows a step increase indicating a rheological change, immediately reduce the stirring speed from 400 rpm to 50 rpm.

[0068] Meanwhile, the cooling rate was slowed down to 0.5℃ / min, and the material was cooled to 4℃. This weak shear condition was maintained for 24 hours.

[0069] Step 5: Transfer the pre-cured oleogel to a constant temperature environment of 25°C and let it stand for 3 days to complete the network curing, thereby obtaining a multi-component oleogel product containing resveratrol.

[0070] Example 3: This example provides a method for preparing a multi-component oleogel loaded with resveratrol, using a high molecular weight polymer gelling agent (ethyl cellulose ECO) system, including the following steps:

[0071] Step 1: Add 78.0% peanut oil, 20.0% ethyl cellulose and 1.0% resveratrol to the reactor by weight percentage.

[0072] The reactor was sealed and filled with high-purity nitrogen to a slightly positive pressure of 0.15 MPa for high-temperature oxidation protection. The system was then heated to 170°C using a heat-conducting oil bath.

[0073] Set the variable frequency stirring speed to 500 rpm and maintain the constant temperature for 30 minutes.

[0074] Meanwhile, 1.0% of Span 60 was heated to 65°C in a separate temporary storage tank for later use.

[0075] Step 2: Switch the heat exchange medium of the reactor and cool it at a cooling rate of 2.0℃ / min.

[0076] During the cooling process, a shearing speed of 500 rpm was maintained, and the material inside the vessel was continuously monitored using a transmittance sensor.

[0077] Step 3: When the transmittance measurement value suddenly drops by 20% (the ethyl cellulose undergoes phase separation and precipitates a polymer network), start the high-pressure feed pump and add liquid Span 60 to the reactor at a uniform rate within 5 minutes through the heated pipeline.

[0078] Step 4: Monitor motor torque changes. When a non-linear step increase in torque occurs due to polymer crosslinking, immediately reduce the stirring speed from 500 rpm to a low-shear mode of 80 rpm.

[0079] The cooling rate was simultaneously reduced to 0.8℃ / min until the temperature inside the autoclave dropped to 2℃, and this state was maintained for 30 hours for curing.

[0080] Step 5: Transfer the obtained polymer oleogel to a constant temperature chamber at 30°C and let it stand for 4 days to eliminate thermal history and internal stress, thereby obtaining the polymer oleogel product.

[0081] Comparative Examples 1-3:

[0082] Comparative Example 1: The difference compared to Example 2 is as follows:

[0083] Using a constant-rate process, 0.6% of Span 60, base oil, gelling agent, and resveratrol are added to the reactor in step 1 and heated to dissolve.

[0084] Meanwhile, during the entire cooling and curing process from step 2 to step 4, the delayed dripping step based on light transmittance and the speed reduction operation based on torque feedback are cancelled, and a constant speed of 400 rpm is maintained throughout until the temperature is cooled to 4°C. All other steps remain the same.

[0085] Comparative Example 2: The difference compared to Example 2 is as follows:

[0086] The surfactant Span 60 was not added to the formulation (the missing 0.6% mass percentage was made up by soybean oil), and the temporary storage and dripping operations in step 3 were cancelled accordingly in the process operation, while the rest were the same.

[0087] Comparative Example 3: The difference compared to Example 2 is as follows:

[0088] In step 4, after the Span 60 drops are finished, the rotation speed is not reduced according to the step increase of torque feedback. Instead, the high shear state of 400 rpm is maintained throughout the entire curing process of cooling down to 4℃ and maintaining it for 24 hours. All other aspects are the same.

[0089] Test Examples 1-4:

[0090] Test Example 1: Online Sensing Response and Phase Change Dynamics Process Verification

[0091] The DCS data acquisition system is activated and connected to the built-in online transmittance sensor and motor spindle torque sensor in the reactor. The system sampling frequency is set to record once every 2 seconds. Real-time data of the reactor during the forced subcooling stage is continuously extracted, including the time axis, material center temperature, relative transmittance calibrated based on the initial homogeneous state, and absolute value of the stirring shaft torque.

[0092] When the system is cooled to the expected phase transition range, auxiliary sampling is carried out. Approximately 15 grams of semi-fluid material is simultaneously extracted every 0.5°C through the bottom circulation pressure measuring port and quickly transferred to the gap of the test plate of the rotational rheometer, which has been pre-cooled to the corresponding sampling temperature.

[0093] The rotational rheometer was set to operate in temperature scanning mode, with a constant logarithmic strain amplitude of 0.1% and an angular frequency of 10 rad / s applied. The specific values ​​of the storage modulus G' and loss modulus G'' of the material were recorded at different offline sampling temperatures. The true gel point temperature corresponding to the intersection of the two curves was determined by plotting the bimodulus change trajectory, and the lateral deviation was compared with the torque mutation trigger temperature automatically captured by the DCS system.

[0094] Table 1. Monitoring data of multidimensional physical quantity coupling at the phase transition critical node in the example.

[0095] Example grouping Optical trigger temperature (°C) Transmittance transient decrease (%) Mechanical trigger temperature (°C) Torque step increment (N·m) Rheological gel point temperature (°C) Example 1 72.4 10.23 68.1 0.42 68.3 Example 2 61.7 14.87 54.2 1.15 54 Example 3 135.2 21.43 128.6 2.87 129.1

[0096] Summarize:

[0097] Based on the test data in Table 1 and Figure 1 Observations of the dynamic response trajectory revealed that the phase transition of the fluid within the reactor exhibited asynchronous characteristics. In previous scale-up studies, the visual blind spots of the sealed equipment made it difficult to accurately define the starting point of component crystallization, affecting the timing of additive addition. Figure 1 The curve trend reveals that during the continuous cooling phase, the decrease in relative transmittance precedes the increase in torque, indicating a lag window between the two. The decrease in transmittance when it crosses the first vertical dotted line indicates the beginning of gelation within the system. The increased internal solid-liquid interface causes light scattering, but has not yet triggered a change in overall fluid viscosity; therefore, the torque curve remains stable within this range. This lag time difference provides a basis for using the optical signal as a trigger threshold, ensuring that Span 60 can achieve dripping and interface anchoring during the stage when the gel skeleton surface area is at its maximum.

[0098] As the system temperature further decreases Figure 1 A step increase in torque occurs after the second vertical dashed line. Comparison with data in Table 1 confirms that the torque trigger temperature coincides with the gel point temperature measured offline by the rotational rheometer, with a deviation consistently within 0.5℃. The increase in torque signifies the beginning of the initial 3D network nodes bridging, the storage modulus exceeding the loss modulus, and the system transitioning to an elastic gel state. Upon detecting this inflection point, the monitoring and control system immediately reduced the stirring speed, mitigating the continuous damage to the initial crosslinking points from a hydrodynamic perspective. This test process achieved online monitoring of the phase transition process in a complex rheological system.

[0099] Test Example 2: Macroscopic Physical Properties and Rheological Testing of Oil Gels

[0100] Each group of gel samples was placed on the texture analyzer test platform, and puncture tests were performed using a P / 0.5R cylindrical probe. The measurement speeds before, during, and after the test were set to 1.0 mm / s, 1.0 mm / s, and 10.0 mm / s, respectively, with a puncture depth of 10 mm and a trigger force of 5 g. The maximum force exerted by the probe during insertion was recorded as an indicator of sample hardness. Each group of samples underwent five parallel independent measurements, and the arithmetic mean of the discrete results was recorded.

[0101] Accurately weigh approximately 2.0 g of a rheologically stable sample and place it into a centrifuge tube of known mass. Centrifuge at 10000 r / min for 15 min at a constant temperature of 25℃. After centrifugation, invert the centrifuge tube onto pre-placed absorbent filter paper and let it stand for 30 min to remove free oil from the surface. Accurately weigh the total mass of the centrifuge tube and the remaining precipitate. Calculate the percentage of oil retained in the three-dimensional network to obtain the oil retention rate of the sample.

[0102] The solid fat content within the system was determined using a pulsed nuclear magnetic resonance (NMR) spectrometer. An equal volume of the sample was placed in a dedicated glass NMR tube and melted in an 80°C heating module for 30 min to completely eliminate the sample's thermal history. The sample was then rapidly transferred to a 0°C ice-water bath and kept there for 60 min to excite nucleation. After equilibration in a 20°C constant-temperature dry bath for 30 min, the sample was placed in the NMR detection chamber to determine the solid mass fraction at the room temperature node.

[0103] Rheological properties were characterized using a rotational rheometer equipped with a Peltier temperature control system. A parallel plate rotor with a diameter of 40 mm was selected, and the working gap was set to 1.0 mm. Strain sweep tests were performed at an ambient temperature of 25 °C, with a fixed oscillation angular frequency of 10 rad / s and a strain variation range set from 0.01% to 100%. The extreme values ​​of the storage modulus in the linear viscoelastic region were extracted as the basic data for evaluating the system's structural stiffness.

[0104] Table 2. Macroscopic physical and rheological characterization data of oleogel samples from the examples and comparative examples.

[0105] Sample group Hardness (N) Oil retention rate (%) Solid fat content (%) at 20℃ Energy storage modulus G' (Pa) in the linear region Example 1 3.14 96.82 11.23 41250 Example 2 5.27 99.96 17.58 85610 Example 3 7.34 98.71 21.04 154380 Comparative Example 1 3.88 89.15 14.62 51220 Comparative Example 2 4.81 94.33 16.91 72540 Comparative Example 3 0.86 62.47 15.34 11460

[0106] Summarize:

[0107] According to the data in Table 2, each embodiment exhibits different physical characteristics under different gelling agent systems. In the development of functional oils, oil retention rate and system hardness are key indicators. Example 3, using a polymer network, achieved a hardness of 7.34 N, and its linear region storage modulus exceeded 1.5 × 10⁻⁶. 5 Pa. The high modulus indicates that the polymer chain segments completed physical entanglement under cooling and weak shear conditions, meeting the textural substitution requirements of baking shortening. Example 2 exhibited moderate hardness and an oil retention rate of 99.96%, indicating that the fiber network formed a capillary-trap structure under the action of surfactant.

[0108] The test results of Comparative Example 3 show the effect of shear force on network assembly. Because the stirring speed was not reduced at the rheological phase transition critical point, the sustained high shear prevented the fiber structure from extending in three-dimensional space, resulting in a decrease in the sample's hardness to 0.86 N and an oil holding capacity to 62.47%. The rheological data in the table further show that the linear region storage modulus of Comparative Example 3 is significantly lower than that of Example 2. This indicates that the gel skeleton was disrupted by shear force in the early stages of crystallization, leading to phase separation of the liquid oil.

[0109] The one-time addition process also had an impact on Comparative Example 1. The constant-rate cooling mode resulted in a mismatch in the phase transition kinetics of the components within the system, and Span 60 failed to effectively accumulate at the interface, reducing the oil holding capacity to 89.15%. Without interfacial molecular protection, nascent grains were prone to agglomeration, forming a rough network, and the reduced crosslinking point density weakened the overall puncture resistance. Furthermore, Comparative Example 2, without surfactants, showed a decline in various indicators, lacking mesoscopic nodes, and the framework built with a single gelling agent was prone to stress concentration. The differences in solid fat content among the samples at constant room temperature in Table 2 suggest that, in actual production, customized lipid carriers adapted to different oral temperatures or resistant to different baking environments can be obtained by switching the basic formulation combination.

[0110] Test Example 3: Verification Test of Active Ingredient Encapsulation Efficiency

[0111] Accurately weigh 2.00 g of the oleogel sample to be tested into a 10 mL centrifuge tube, and add 5.0 mL of anhydrous ethanol as the washing solvent. Vortex gently at room temperature for 3 minutes to fully dissolve the resveratrol adhering to the surface of the gel network and in the exudated free oils into the ethanol phase. Then centrifuge the mixture at 8000 rpm for 10 minutes, and carefully transfer the supernatant to a volumetric flask. Repeat the washing and centrifugation steps twice, combine the supernatants, and dilute to volume. Filter through a 0.45 μm organic filter membrane to obtain the free resveratrol extract.

[0112] Separately, weigh 2.00 g of the same gel sample into a 50 mL stoppered conical flask and add 20.0 mL of a mixed solvent of isopropanol and chloroform (volume ratio 1:1). Place the flask in a 60 °C water bath and heat at a constant temperature, followed by sonication for 15 minutes to completely disrupt the three-dimensional gel network structure of the system, forcing all the embedded resveratrol to be released into the mixed solvent. After cooling to room temperature, centrifuge and filter the supernatant to obtain the total resveratrol extract.

[0113] The concentration of resveratrol in the above extract was quantitatively analyzed using a high-performance liquid chromatograph equipped with a UV detector. A C18 reversed-phase column was used, with the mobile phase set to an isocratic elution system of methanol and water (65:35 v / v), the flow rate controlled at 1.0 mL / min, and the detection wavelength set at 306 nm. The free mass and total mass were calculated by comparing with the standard solution. The difference between the two was divided by the mass of the gel sample to obtain the actual loading rate, and the ratio of this difference to the total mass was calculated as the embedding efficiency.

[0114] To verify the protective effect of the system on the active substances, the freshly prepared gel samples of each group were sealed and stored in a 25°C incubator in the dark for 30 days. After the storage period, the aforementioned demulsification extraction and chromatographic quantification steps were repeated, and the percentage of residual resveratrol in the sample relative to the initial total amount was calculated, which was used as the retention rate index for evaluating chemical stability.

[0115] Trace amounts of the example samples and pure raw materials were extracted and analyzed using an attenuated total reflectance Fourier transform infrared spectrometer at 4000 to 400 cm⁻¹. -1 The wavenumber range was scanned, and the embedding mechanism was confirmed by the frequency shift of the molecular characteristic absorption peaks.

[0116] Table 3. Data on resveratrol loading efficiency and storage stability in the examples and comparative examples

[0117] Sample group Actual loading rate (mg / g) Encapsulation rate (%) Retention rate (%) after 30 days of storage at 25℃ Example 1 0.98 98.15 94.2 Example 2 4.97 99.64 97.8 Example 3 9.62 96.31 95.4 Comparative Example 1 3.91 78.42 81.3 Comparative Example 2 2.73 54.18 66.7 Comparative Example 3 3.06 61.53 72.4

[0118] Summarize:

[0119] Figure 2 The infrared absorption characteristics of different components are shown. The solid black line in the figure represents pure resveratrol at 3280 cm⁻¹. -1 A stretching vibration absorption peak of the phenolic hydroxyl group (-OH) caused by intramolecular or intermolecular hydrogen bonding is present nearby. The black dashed line represents the matrix gel without resveratrol and Span 60, showing the lipid absorption peak at 2922 cm⁻¹. -1 2853cm -1 and 1743cm -1 The peaks at the carbon-hydrogen bond and carbonyl group are visible. The black dotted line at the bottom is the scan spectrum of the product from Example 2, where the peak at 3280 cm⁻¹, which originally belonged to resveratrol, can be observed. -1 The hydroxyl peak shifted towards higher frequencies (blue shift), and the absorption band moved to 3345 cm⁻¹. -1 Nearby, and the peak shape exhibits a broadening characteristic.

[0120] Based on the data in Table 3 and Figure 2 Analysis of the spectral characterization results showed that the reaction sequence affected the loading effect of the active substance. In multiphase food carrier engineering, avoiding the loss of easily oxidized small molecules at the interface is a common technical problem. Example 2 achieved an actual loading of 4.97 mg / g and an encapsulation rate of 99.64%, indicating that the delayed feeding process improved the encapsulation effect. Combined with... Figure 2 The broadening shift of the hydroxyl peak in the mid-infrared spectrum to the high-frequency region confirms that resveratrol is not suspended in the oil liquid phase in a free microcrystalline state. The added Span 60 forms a ternary association through hydrogen bonding, binding the functional component within the crystalline network framework.

[0121] Comparative data provided reverse verification. In Comparative Example 1, which used a co-heating and cooling process, the surfactant molecules were randomly distributed in the oil phase due to the inability to control the diffusion timing of Span 60. Resveratrol molecules were distributed outside the network along with the oil phase during cooling, resulting in an encapsulation rate of 78.42%. In Comparative Example 2, without added surfactant, the encapsulation rate decreased to 54.18%. Comparative Example 3, which did not slow down, suffered from low encapsulation rates due to shearing disruption of hydrogen bonds and the network framework, exposing trapped molecules to the free flow field. This structural defect easily leads to chemical degradation during subsequent storage tests. Unencapsulated free resveratrol is susceptible to dissolved oxygen and light attack, and the retention rate of the comparative samples decreased significantly after 30 days. In contrast, the examples, thanks to the steric hindrance effect provided by the dense network and hydrogen bond anchoring, maintained over 94% chemical stability during storage, meeting the requirements for functional component retention.

[0122] Test Example 4: In vitro lipolysis and bioavailability regulation test

[0123] A simulated digestive fluid system was prepared, comprising simulated saliva fluid (SSF), simulated gastric fluid (SGF), and simulated small intestinal fluid (SIF). During preparation, corresponding electrolytes and digestive enzymes were added according to the target physiological environment. All simulated digestive fluids were preheated in a 37°C constant temperature water bath before use.

[0124] Approximately 2.0 g of stable oleogel sample was weighed and placed in a temperature-controlled, jacketed reaction vessel. An equal volume of SSF system was added, and the mixture was magnetically stirred at 37°C for 5 minutes to simulate oral chewing and saliva wetting. Subsequently, SGF system was added at a volume ratio, and the pH of the system was adjusted to 2.0 with 1.0 mol / L hydrochloric acid solution. After adding pepsin, the mixture was incubated for 120 minutes under continuous light-protected stirring.

[0125] After the simulated gastric digestion, preheated SIF system and a mixture of pancreatic lipase extract and bile salts were added to the reaction vessel. The pH of the system was adjusted back to 7.0 using a 0.5 mol / L sodium hydroxide solution. An automatic potentiometric titrator (pH-stat mode) was connected, and sodium hydroxide solution was automatically added dropwise during a 120-minute simulated small intestinal digestion period to neutralize the free fatty acids produced by triglyceride hydrolysis, maintaining a constant pH. The volume of sodium hydroxide consumed throughout the titration process was recorded, and the final percentage of free fatty acids released was calculated based on the set molar mass and the initial mass of the oil phase, thus characterizing the degree of lipolysis.

[0126] After the small intestine digestion is completed, the mixed digestive fluid is immediately transferred to a centrifuge tube and centrifuged at 50,000 g for 40 minutes at 4°C. Centrifugation separates the digestive system into a top layer of undigested lipids, a middle layer of clear aqueous phase containing mixed micelles, and a bottom layer of sediment.

[0127] The middle micelle phase fluid was carefully extracted using a syringe to penetrate the upper lipid layer. An appropriate amount of the micelle phase solution was diluted and demulsified with methanol, filtered through a 0.22 μm pore size filter membrane, and then injected into a high-performance liquid chromatograph. The content of resveratrol dissolved in the micelle layer was determined, and the ratio of this mass to the initial total load mass in the sample was calculated to obtain the in vitro bioavailability data.

[0128] Table 4. In vitro lipolysis parameters and bioavailability test data of the examples and comparative samples

[0129] Sample group Sodium hydroxide consumption (mL) Final release rate of free fatty acids (%) Micellar layer content (mg) Resveratrol bioavailability (%) Example 1 6.82 62.14 1.15 58.37 Example 2 8.13 75.82 7.08 71.22 Example 3 5.34 48.65 8.65 45.01 Comparative Example 1 5.86 53.21 3.26 41.56 Comparative Example 2 6.75 61.34 1.58 28.93 Comparative Example 3 8.87 81.12 2.05 33.47

[0130] Summarize:

[0131] According to the data in Table 4, the digestive behavior of each sample in an in vitro simulated gastrointestinal environment showed structure-related differences. In the lipid carrier study, the interfacial release kinetics of free fatty acids affected the release and absorption of active substances. Example 2 showed a lipolysis rate of 75.82%, corresponding to the relatively easy dissociation of its selected sitosterol and oryzanol fiber network under bile salt molecule replacement. The final lipolysis rate of Example 3 was 48.65%. The polymer-formed network created steric hindrance, slowing down the contact between pancreatic lipase and triglycerides. This indicates that the degradation rate of the carrier can be controlled by adjusting the formulation.

[0132] The degradation rate of the skeletal framework also affects the absorption of active substances. In Example 2, while achieving a moderate digestibility, the bioavailability of resveratrol in the micelle phase reached 71.22%, and even in Example 3, where degradation was slowest, it remained above 45%. In Comparative Example 2, due to the absence of Span 60, the bioavailability decreased to 28.93%. In the absence of surfactants, the released resveratrol is difficult to form micelles and easily aggregates into precipitates. This indicates that the added Span 60 participates in the reconstruction of the emulsion interface during digestion.

[0133] Deviations in process parameters also led to limited absorption. Comparative Example 3, due to the lack of rate reduction in the early stages, resulted in the disintegration of the crystalline network, with an apparent lipolysis rate of 81.12%, but an actual bioavailability of only 33.47%. Free resveratrol, stripped of its skeletal barrier protection, was prematurely exposed in simulated gastric juice, making it susceptible to chemical degradation and affecting subsequent absorption. Comparative Example 1, using a constant process, also exhibited random degradation during enzymatic hydrolysis due to the irregular distribution of encapsulation sites. The test results indicate that adding exogenous interfacial molecules at phase transition nodes can improve the microstructure of multiphase systems and enhance the bioavailability of active substances in the digestive tract.

Claims

1. A multi-component oleogel loaded with resveratrol, characterized in that, Made from the following raw materials by weight percentage: The composition of the base oil is 78.0%-89.7%, the gelling agent is 10.0%-20.0%, the resveratrol is 0.1%-1.0%, and the surfactant is 0.2%-1.0%. The base oil is soybean oil or peanut oil; The gelling agent is carnauba wax, ethyl cellulose, or a composite material composed of β-sitosterol and lecithin; The surfactant is Span 60.

2. The multi-component oleogel loaded with resveratrol according to claim 1, characterized in that, When the gelling agent is a composite material composed of β-sitosterol and lecithin, the mass ratio of β-sitosterol to lecithin is 4:

1.

3. The multi-component oleogel loaded with resveratrol according to claim 1, characterized in that, It is made from the following ingredients by weight percentage: 89.7% soybean oil, 10.0% carnauba wax, 0.1% resveratrol, and 0.2% Span 60.

4. The multi-component oleogel loaded with resveratrol according to claim 1, characterized in that, It is made from the following ingredients by weight percentage: 82.9% soybean oil, 16.0% composite material composed of β-sitosterol and lecithin, 0.5% resveratrol and 0.6% Span 60.

5. A method for preparing a multi-component oleogel loaded with resveratrol, used to prepare the multi-component oleogel loaded with resveratrol as described in any one of claims 1-4, characterized in that, Includes the following steps: Add the base oil, gelling agent and resveratrol into a sealed reactor according to the set mass percentage, remove the air and fill with high-purity nitrogen to a slight positive pressure, start the variable frequency stirrer to perform high shear stirring, and heat the system to make it reach a thermodynamic homogeneous dispersion state. During this period, the surfactant is heated and melted separately for later use; When switching cooling media, the system is forced to cool down at the first cooling rate. During the cooling process, high shear stirring is maintained, and the transmittance of the material in the reactor is continuously monitored by an online transmittance sensor. When the measured transmittance value suddenly drops from the initial homogeneous state to the critical point of phase transition, the liquid surfactant is added dropwise into the sealed reaction vessel at a uniform rate. After the surfactant is added, the torque feedback value of the stirring spindle motor is monitored. When the torque feedback value shows a step increase, the stirring speed is immediately reduced to enter a weak shear state, and the cooling rate is reduced to the second cooling rate to cool the material to the preset low temperature for initial solidification. The pre-cured product is removed and transferred to a constant temperature environment for static curing to eliminate internal stress, thereby obtaining the multi-component oleogel.

6. The preparation method according to claim 5, characterized in that, The pressure range for filling with high-purity nitrogen to a slightly positive pressure is 0.05MPa-0.15MPa; The target temperature for heating the system is 70℃-170℃, the high-shear stirring speed is 300rpm-500rpm, and the constant temperature is maintained for 20min-30min.

7. The preparation method according to claim 5, characterized in that, The temperature at which the surfactant is heated and melted separately for later use is 60℃-65℃; The first cooling rate is 1.0℃ / min-2.0℃ / min.

8. The preparation method according to claim 5, characterized in that, Reaching the critical point of phase transition refers to a sudden drop in the measured transmittance value of 10%-20% compared to the initial homogeneous state. The liquid surfactant is added dropwise to the sealed reaction vessel at a uniform rate over a period of 2-5 minutes.

9. The preparation method according to claim 5, characterized in that, After adjusting the stirring speed to enter the weak shear state, the stirring speed is 30rpm-80rpm. The second cooling rate is 0.3℃ / min-0.8℃ / min.

10. The preparation method according to claim 5, characterized in that, The preset low temperature is 2℃-6℃, and the initial curing time is 18h-30h; The constant temperature environment is 20℃-30℃, and the standing curing time is 2d-4d.

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