Rice bran oil gel and preparation method and application thereof

Abstract

The application discloses a rice bran oil gel and a preparation method and application thereof. The rice bran oil gel is composed of rice bran oil rich in natural orpen wax (0.5%-3% orpen wax) obtained by supercritical CO2 extraction of rice bran and added gelling agent beeswax or monoglyceride (6%-10% addition amount). In the preparation, the added gelling agent is added to the rice bran oil, stirred and dissolved by heating to 80-90 DEG C, and then cooled and crystallized to obtain the rice bran oil gel. The application utilizes the synergistic crystallization of natural orpen wax and the added gelling agent, and a stable gel network with oil binding capacity ≥95%, DPPH and ABTS free radical scavenging rate ≥95% can be formed at 6%-8% addition amount. The rice bran oil gel can completely replace butter in baked foods, significantly reduce the fat content, increase the dietary fiber content, and realize high-value utilization of rice bran resources.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically a rice bran oil gel, its preparation method, and its application. Background Technology

[0002] Rice bran, a byproduct of rice processing, is rich in various nutrient-active substances such as oils, dietary fiber, oryzanol, vitamin E, and phytosterols. Rice bran oil has high nutritional value and a balanced fatty acid composition, making it a high-quality edible oil. However, as a liquid oil, rice bran oil has poor plasticity and cannot directly replace solid oils such as butter and shortening in baking, thus limiting its further processing and utilization in the food industry.

[0003] Oil gel technology uses a gelling agent to construct a three-dimensional network structure, fixing liquid oils within the network to form a novel type of oil product with solid plasticity that can replace traditional hydrogenated oils and butter, meeting the processing requirements of low-fat and healthy foods. However, existing oil gel technologies generally suffer from the following drawbacks: First, most existing technologies use commercially available refined dewaxed rice bran oil as raw material. After refining and dewaxing, a large amount of natural bran wax, oryzanol and other active ingredients in the rice bran oil are lost. It can only rely on adding a large amount of external gelling agents (beeswax, monoglycerides, stearic acid, etc.) to form a gel structure. The amount of external gelling agents added is usually as high as 8% to 15%, which not only makes the production cost high, but also leads to the product having a greasy taste and poor flavor.

[0004] Secondly, most existing oleogels are formed by crystallizing a single external gelling agent into a network. The network structure is loose, with poor oil holding capacity. During storage, problems such as oil precipitation, stratification, and decreased stability are prone to occur, resulting in a short product shelf life.

[0005] Third, rice bran has a low processing utilization rate, with most defatted rice bran being discarded or treated at low value, resulting in serious waste of resources. At the same time, ordinary rice bran oil has poor oxidative stability and is prone to rancidity and deterioration after being made into oil products, requiring the addition of synthetic antioxidants, which does not conform to the production concept of natural and healthy foods. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a rice bran oil gel, its preparation method, and its applications. The core of this invention lies in the following: Supercritical fluid extraction is used to directly extract rice bran oil rich in natural rice bran wax, which retains the natural rice bran wax component. A small amount of excipient gelling agent is then added, and the synergistic crystallization effect of the natural rice bran wax and the excipient gelling agent is utilized to construct a three-dimensional network structure with excellent performance. This solves the problem of insufficient stability in naturally occurring rice bran oil rich in rice bran wax. Unexpectedly, this combination can significantly reduce the amount of excipient gelling agent used, while simultaneously improving the oil-binding capacity and antioxidant activity of the gel.

[0007] Another object of the present invention is to provide a method for preparing the rice bran oil gel.

[0008] Another object of the present invention is to provide the application of the rice bran oil gel in the preparation of baked goods.

[0009] Another object of the present invention is to provide a rice bran biscuit comprising the rice bran oil gel and defatted rice bran.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a rice bran oil gel, which is composed of rice bran oil rich in natural bran wax and an added gelling agent; The rice bran oil rich in natural bran wax is extracted directly from rice bran using supercritical fluid extraction technology, and the mass percentage of natural bran wax in the rice bran oil is 0.5% to 3%. The added gelling agent is at least one of beeswax or monoglyceride, and its addition amount is 6% to 10% of the mass of rice bran oil; The rice bran oil gel has a three-dimensional network structure formed by the co-crystallization of natural rice bran wax and an added gelling agent, with an oil binding capacity of ≥95% and DPPH free radical scavenging rate and ABTS free radical scavenging rate of ≥95%.

[0011] In a preferred embodiment of the present invention, the added gelling agent is beeswax, and its addition amount is 6% to 10% of the mass of rice bran oil. Under this preferred embodiment, beeswax and the natural bran wax in rice bran oil form a synergistic crystallization effect, which can further improve the hardness and thermal stability of the gel.

[0012] In another preferred embodiment of the present invention, the added gelling agent comprises beeswax and monoglycerides, with a total addition amount of 6% to 8% of the mass of rice bran oil, wherein the mass ratio of beeswax to monoglycerides is 1:3 to 3:1. The combined use of beeswax and monoglycerides can regulate the crystallization morphology and network density of the gel, thereby optimizing the texture and mouthfeel of the gel.

[0013] As a further preferred embodiment of the present invention, the supercritical fluid extraction technology is supercritical CO2 extraction, and the extraction conditions include: extraction temperature of 45℃~55℃, extraction time of 1.5h~2.5h, and extraction pressure of 25MPa~35MPa. Under these conditions, the natural bran wax and active ingredients such as oryzanol and phytosterols in rice bran can be preserved to the greatest extent, while ensuring extraction efficiency and oil quality.

[0014] Secondly, the present invention provides a method for preparing the aforementioned rice bran oil gel, comprising the following steps: S1. Rice bran oil rich in natural bran wax is extracted from rice bran using supercritical fluid extraction technology. The rice bran is stabilized rice bran that has been treated with saturated steam at 121℃ for 15 min to 25 min. S2. Add the external gelling agent to the rice bran oil rich in natural rice bran wax obtained in step S1, and mix to obtain a mixture; S3. Heat the mixture to 80℃~90℃ and stir at a constant temperature until the added gelling agent is completely dissolved to form a uniform and transparent mixed oil. S4. Cool the mixed oil and allow it to stand and crystallize, wherein the standing temperature is 4℃~25℃ and the standing time is 12h~24h, so that it crystallizes and solidifies to obtain the rice bran oil gel.

[0015] In a preferred embodiment of the method of the present invention, the heating temperature in step S3 is 85°C, and the stirring time is 20-30 minutes; the cooling in step S4 involves first allowing the mixture to cool to 45°C, and then placing it at 4°C for 18 hours. This segmented cooling method is beneficial for forming a more uniform and dense three-dimensional network structure.

[0016] Thirdly, the present invention provides the application of rice bran oil gel as described above or rice bran oil gel prepared by the aforementioned method in the preparation of baked goods, characterized in that the rice bran oil gel is used as a substitute for butter in the preparation of low-fat baked goods.

[0017] Furthermore, the low-fat baked goods are biscuits, cakes, or cookies.

[0018] Fourthly, the present invention provides a rice bran biscuit, wherein the raw materials for preparing the rice bran biscuit include rice bran oil gel as described above, and defatted rice bran obtained by supercritical CO2 extraction of rice bran; the rice bran oil gel completely replaces butter, and the amount of defatted rice bran added is 5% to 15% of the total raw material mass of the biscuit.

[0019] Preferably, the amount of defatted rice bran added is 8% to 12% of the total raw material mass of the biscuits. This method achieves full utilization of rice bran raw materials, that is, the high-value rice bran oil obtained by supercritical extraction is used to prepare gel, and the remaining nutrient-rich defatted rice bran is returned to the biscuits as dietary fiber and functional ingredients, thereby improving the nutritional value and economic efficiency of the product.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention is the first to propose using supercritical fluid extraction technology to directly extract rice bran oil rich in natural bran wax from rice bran, and then combining it with an external gelling agent to construct an oleogel. Supercritical CO2 extraction is carried out under mild conditions, which can retain the active ingredients such as natural bran wax, oryzanol, and tocopherol in rice bran to the greatest extent. The content of natural bran wax can reach 0.5% to 3%, providing a natural nucleating agent and structural enhancer for subsequent gel network construction.

[0021] 2. This invention discovers the synergistic effect of natural rice bran wax and added gelling agents. Experiments show that in rice bran oil rich in natural rice bran wax, only 6%–8% of added gelling agent (especially beeswax) is needed to form a stable gel network with an oil-binding capacity of ≥95%, significantly lower than the amount of added gelling agent required for the preparation of oil gels from conventional refined oils (usually 10%–15%). The mechanism of this synergistic effect may be that natural rice bran wax preferentially crystallizes during cooling to form a primary network, providing nucleation sites for the crystallization of the added gelling agent, and the two together construct a more dense and ordered three-dimensional network structure.

[0022] 3. The rice bran oil gel prepared by this invention possesses excellent functional properties. Its oil-binding capacity reaches 99.23%, and its DPPH and ABTS free radical scavenging rates both exceed 99%, exhibiting extremely strong antioxidant activity. This is mainly due to the physical protection of the oil by the natural antioxidants (oryzanol and tocopherol) retained by supercritical extraction and the gel network, which significantly improves the oxidative stability of the gel.

[0023] 4. This invention successfully applies rice bran oil gel to baked goods, completely replacing butter in the preparation of high-fiber rice bran biscuits. Results show that using the rice bran oil gel of this invention can significantly reduce the fat content of biscuits (by approximately 10%) and increase the dietary fiber content (to 6.05%), while maintaining good taste, flavor, and consumer acceptance, providing a new approach for the development of healthy baked goods.

[0024] 5. This invention realizes the high-value utilization of rice bran resources: First, the problem of easy rancidity of rice bran is solved by saturated steam stabilization treatment. Then, high-quality rice bran oil and defatted rice bran are obtained by supercritical extraction. The rice bran oil is further used to prepare functional oil gels, and the defatted rice bran is used as a source of dietary fiber in biscuits, forming a complete high-value utilization technology chain of rice bran, which has good economic and social benefits. Attached Figure Description

[0025] Figure 1 This is a process flow diagram for preparing rice bran oil gel according to the present invention; Figure 2 Photographs of rice bran oil gel samples with different added gelling agents and amounts; Figure 3Polarized light microscopy (PLM) images of rice bran oil gels with different amounts of added gelling agents; Figure 4 The effect of different added gelling agents on the oil-gel binding capacity (OBC) of rice bran oil is shown in the figure. Figure 5 Fourier transform infrared (FTIR) spectra of rice bran oil gels with different added gelling agents; Figure 6 XRD diffraction patterns of rice bran oil gels with different added gelling agents; Figure 7 Differential scanning calorimetry (DSC) curves of rice bran oil gels with different added gelling agents and amounts are shown; where A and C are the heat flow changes of MG rice bran oil gel during heating and cooling processes, respectively; and B and D are the heat flow changes of BW rice bran oil gel during heating and cooling processes, respectively. Figure 8 Low-field nuclear magnetic resonance (LF-NMR) spectra of rice bran oil gels with different added gelling agents and amounts; Figure 9 The rheological properties of rice bran oil gels prepared with different added gelling agents and amounts are shown in the figure. A is the frequency scan, B is the apparent viscosity, and C is the temperature scan. Figure 10 Figure 1 shows the effect of different added gelling agents and their amounts on the DPPH and ABTS free radical scavenging rates of rice bran oil gel. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below. The description in this part is only exemplary and explanatory, and should not be used to limit the scope of protection of the present invention in any way.

[0027] Wax-rich rice bran oil raw material: The wax-rich rice bran oil prepared by this invention is obtained by supercritical CO2 extraction. The wax content of the rice bran is controlled at 0.5%~3%. The rice bran is pretreated and stabilized by saturated steam, and then extracted by supercritical CO2 at an extraction temperature of 35-45℃, a pressure of 25-35MPa, and an extraction time of 1.5-2.5h. This process is gentle and non-destructive, and can completely preserve the natural antioxidants such as oryzanol, vitamin E, and phytosterols in the rice bran oil, as well as the endogenous wax components, laying the foundation for synergistic gelation.

[0028] Rice bran oil gel components: In a preferred embodiment, the rice bran oil gel comprises the following components by mass percentage: 92%~94% wax-rich rice bran oil and 6%~8% added gelling agent; the added gelling agent is a compound of beeswax and monoglycerides, and the mass ratio of beeswax to monoglycerides is (1-2):1.

[0029] This invention provides a method for preparing the aforementioned rice bran oil gel, such as... Figure 1 As shown; Step 1: Rice bran pretreatment, using saturated steam for stabilization treatment to kill lipase and prevent oil oxidation and rancidity; Step 2: Supercritical CO2 extraction. Stabilized rice bran is placed in an extraction vessel, and the temperature is set to 35-45℃ and the pressure to 25-35MPa. Extraction is carried out for 1.5-2.5 hours, and wax-rich rice bran oil with a wax content of 0.5%~3% is collected. Step 3: Mix and heat. Mix the wax-rich rice bran oil with the added gelling agent, heat to 75-85℃, and keep warm while stirring until the gelling agent is completely dissolved to obtain a uniform oil mixture. Step 4: Segmented cooling and molding. First, rapidly cool to 45-55℃, keep warm for 10-15 minutes, then slowly cool to 20-30℃, and let stand to form, to obtain rice bran oil gel.

[0030] Synergistic Mechanism: This invention employs a gel-forming mechanism of synergistic crystallization of endogenous natural rice bran wax and added gelling agents: the natural rice bran wax in wax-rich rice bran oil has a moderate melting point and a fast crystallization rate, and crystallizes out first during the cooling process, forming a fine and uniform crystal nucleus skeleton, which builds a basic three-dimensional network; subsequently, added gelling agents such as beeswax and monoglycerides use the rice bran wax crystal nuclei as attachment points, grow in a directional manner, and overlap tightly to form a composite gel network with smaller pore size, higher cross-linking degree, and more stable structure.

[0031] This synergistic mechanism can significantly reduce the amount of external gelling agent required, with only 6% to 8% of the total amount needed to achieve an oil-binding capacity of ≥95% and prevent oil precipitation. At the same time, the natural active substances such as oryzanol, vitamin E, and phytosterols retained in rice bran oil can be embedded in the gaps of the gel network. On the one hand, they can play a role in scavenging free radicals, with DPPH and ABTS free radical scavenging rates of ≥95%. On the other hand, they can achieve long-lasting antioxidant effect by physically blocking oxygen, moisture and oil from contact, without the need to add additional synthetic antioxidants.

[0032] The present invention will be further described below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the technical solutions described in the present invention are conventional technical solutions in the art; the reagents or materials described, unless otherwise specified, are all from commercial sources.

[0033] The rice bran raw material used in the example was fresh rice bran (provided by Hunan XX Rice Industry Co., Ltd.), which was stabilized before use: it was treated with saturated steam at 121℃ for 20 minutes to reduce the activity of rice bran lipase from 79.71±6.35mg / g to 19.87±1.06mg / g, thus obtaining stabilized rice bran.

[0034] The supercritical CO2 extraction equipment used in the examples was a HA-220-50-06-C type (Nantong XX Supercritical Extraction Co., Ltd.); the subcritical extraction equipment was a CBE-20L type (Henan XX Critical Machinery Equipment Co., Ltd.); beeswax was from XX Agricultural Technology Co., Ltd.; monoglycerides were from XX Food Technology Co., Ltd. in Zhengzhou; and all other reagents were of analytical grade.

[0035] Oil-binding capacity (OBC) determination method: Centrifugation method is used. Weigh 1g of oil gel into a 5mL centrifuge tube, centrifuge at 10000rpm for 10min, invert the centrifuge tube for 1h after centrifugation to remove unadsorbed oil and weigh it, and calculate OBC according to the formula.

[0036] DPPH free radical scavenging rate determination method: Prepare a 0.1 mmol / L DPPH solution with anhydrous ethanol, mix the sample solution with the DPPH solution, let it stand in the dark at room temperature for 30 min, and then measure the absorbance at 517 nm to calculate the scavenging rate.

[0037] Method for determining ABTS free radical scavenging rate: Prepare ABTS stock solution (7.4 mmol / L) and potassium persulfate stock solution (2.6 mmol / L), mix them at a 1:1 ratio, and let them stand in the dark for 12-16 h. Dilute the mixture 30 times with anhydrous ethanol to obtain the ABTS working solution. Mix the sample with the ABTS solution, allow the reaction to proceed, and then measure the absorbance at 734 nm to calculate the scavenging rate.

[0038] Example 1: Preparation of rice bran oil rich in natural rice bran wax 200g of stabilized rice bran was placed in a 1L extraction vessel of a supercritical CO2 extraction apparatus. Food-grade CO2 was introduced, and extraction was carried out for 2 hours at an extraction temperature of 50℃, an extraction pressure of 30MPa, a separation temperature of 45℃, and a separation pressure of 10MPa. After extraction, the rice bran oil was collected in the separation vessel. Analysis showed that the obtained rice bran oil contained 1.86% natural bran wax, 1.52% oryzanol, and 0.08% tocopherol. The oil extraction efficiency of the rice bran reached 94.15%.

[0039] Comparative Example 1: Preparation of ordinary refined rice bran oil Commercially available crude rice bran oil is processed using conventional refining processes (degumming, deacidification, decolorization, and deodorization) to obtain refined rice bran oil. Testing revealed that the refined rice bran oil contains less than 0.1% natural rice bran wax and less than 0.2% oryzanol.

[0040] Example 2: Preparation of beeswax-based rice bran oil gel 10g of rice bran oil rich in natural rice bran wax prepared in Example 1 was placed in a 50mL beaker and heated to 85°C on a constant-temperature magnetic stirrer. Beeswax was added at 2%, 4%, 6%, 8%, and 10% of the rice bran oil mass, respectively, and stirred for 25 minutes until completely dissolved, forming a homogeneous and transparent mixed oil. The mixture was first allowed to cool to 45°C at room temperature, and then placed in a 4°C refrigerator for 18 hours to crystallize and solidify, yielding rice bran oil gels with beeswax additions of 2%, 4%, 6%, 8%, and 10%, respectively, labeled as BW-2%, BW-4%, BW-6%, BW-8%, and BW-10%.

[0041] Example 3: Preparation of monoglyceride-based rice bran oil gel The difference from Example 2 is that beeswax was replaced with monoglycerides, resulting in rice bran oil gels with 2%, 4%, 6%, 8%, and 10% monoglyceride addition, labeled as MG-2%, MG-4%, MG-6%, MG-8%, and MG-10%, respectively.

[0042] Comparative Example 2: Preparation of ordinary refined rice bran oil gel Take 10g of the ordinary refined rice bran oil prepared in Comparative Example 1, add beeswax at 8% of the mass of the rice bran oil, and follow the same steps as in Example 2 to obtain ordinary refined rice bran oil gel (labeled as Refined-8%).

[0043] Comparative Example 3: Control group without added gelling agent Take 10g of rice bran oil rich in natural rice bran wax prepared in Example 1, without adding any external gelling agent, and process it directly according to the heating and cooling procedure of Example 2, and observe the gel formation.

[0044] Example 4: Characterization of rice bran oil gel properties The performance of the samples prepared in Examples 2-3 and Comparative Examples 2-3 was tested, and the results are as follows: 4.1 Macroscopic and Microscopic Structural Observation Macroscopic photography and polarized light microscopy (PLM) were performed on the rice bran oil gels prepared in Examples 2-3. The results showed that ( Figure 2-3 As the amount of added gelling agent increases, the structure of rice bran oil gel gradually becomes denser, and its crystallization properties are significantly enhanced. When the amount of added gelling agent is 2%, the gel structure is relatively loose; when the amount reaches 8%-10%, the crystal grains in the gel are evenly and densely distributed, forming a complete three-dimensional network structure. The crystal structure of beeswax-based gel is more regular and ordered than that of monoglyceride-based gel.

[0045] Comparative Example 3 (without added gelling agent) remained a flowing liquid after cooling and failed to form a gel, indicating that natural rice wax (1.86%) alone is insufficient to form a stable gel network, and an added gelling agent is required as a stabilizer.

[0046] 4.2 Oil Binding Capacity (OBC) Analysis The oil binding capacity of different samples was measured, and the results are as follows: Figure 4 As shown in Table 1, the OBC of the rice bran oil gel prepared in Examples 2-3 increased with increasing amounts of added gelling agent, reaching an optimal value at an addition amount of 8%. Specifically, the OBC of BW-8% in Example 2 reached 99.23%, and the OBC of MG-8% in Example 3 reached 96.35%. The OBC of Comparative Example 2 (Refined-8%) was only 87.56%, significantly lower than the samples of the same concentration in Examples 2-3. This indicates that rice bran oil rich in natural bran wax and the added gelling agent have a significant synergistic effect, achieving excellent oil-binding capacity at relatively low addition amounts.

[0047] Table 1 Comparison of oil binding capacity of different samples

[0048] 4.3 Antioxidant Activity Analysis The DPPH and ABTS free radical scavenging rates of different samples were determined, and the results are as follows: Figure 10 As shown in Table 2, the antioxidant activity of the rice bran oil gels prepared in Examples 2-3 significantly increased with the increase of the amount of exogenous gelling agent added. Specifically, in Example 2, the DPPH scavenging rate of BW-8% reached 99.79%, and the ABTS scavenging rate reached 99.81%; in Example 3, the DPPH scavenging rate of MG-8% reached 98.52%, and the ABTS scavenging rate reached 98.74%. The DPPH scavenging rate of Comparative Example 2 (Refined-8%) was only 72.35%, and the ABTS scavenging rate was 70.18%, significantly lower than that of Examples 2-3. This indicates that the natural antioxidants (oryzanol and tocopherol) retained by supercritical extraction endow the rice bran oil gel with excellent antioxidant properties.

[0049] Table 2 Comparison of antioxidant activities of different samples

[0050] 4.4 Thermal Stability Analysis (DSC) DSC analysis was performed on the rice bran oil gels prepared in Examples 2-3, and the results are as follows: Figure 7 As shown, the melting temperature range of beeswax-based rice bran oil gel is 60-75℃, and the crystallization temperature range is 50-60℃; the melting temperature range of monoglyceride-based rice bran oil gel is 40-50℃, and the crystallization temperature range is 30-40℃. The beeswax-based gel exhibits higher melting and crystallization temperatures, demonstrating better thermal stability. With increasing amounts of added gelling agent, both the melting and crystallization temperatures slightly increase, indicating a more dense and stable gel network structure.

[0051] 4.5 Rheological property analysis The rheological properties of the rice bran oil gels prepared in Examples 2-3 were tested, and the results are as follows: Figure 9 As shown, the storage modulus (G') of all samples is greater than the loss modulus (G"), exhibiting solid-fluid-like behavior. With increasing amounts of added gelling agent, both G' and G" gradually increase, indicating the formation of a stronger gel network. Apparent viscosity tests show that all samples exhibit shear-thinning characteristics, with viscosity decreasing with increasing shear rate, typical of pseudoplastic fluid behavior.

[0052] 4.6 Low-field NMR analysis Low-field NMR analysis was performed on the rice bran oil gels prepared in Examples 2-3, and the results are as follows: Figure 8 As shown in Table 3, the relaxation time decreased with increasing amounts of added gelling agent, indicating a tighter gel network and increased restriction on the movement of oil molecules. The relaxation time of the beeswax-based gel was lower than that of the monoglyceride-based gel, and the peak area fluctuated less, indicating that the beeswax system had a stronger binding ability on oils and a more stable gel structure.

[0053] Table 3 Low-field NMR relaxation data for different samples

[0054] Example 5: Application of rice bran oil gel in biscuits The BW-8% rice bran oil gel prepared in Example 2 was selected and applied to the preparation of high dietary fiber rice bran biscuits.

[0055] Basic cookie recipe (based on 100g of low-gluten flour): 40g rice bran oil gel, 30g egg, 30g granulated sugar, 10g defatted rice bran (Zq-SFE defatted rice bran, prepared in our laboratory). The control group used butter instead of rice bran oil gel, with the rest of the recipe remaining the same.

[0056] Preparation process: Beat rice bran oil gel (or butter) with granulated sugar until fluffy. Add egg liquid in batches and mix well. Add sifted low-gluten flour and defatted rice bran, knead into a dough, refrigerate and relax for 30 minutes, roll out into a 3mm thick sheet, press into shape with a mold, and bake in a preheated oven at 160℃ top heat and 175℃ bottom heat for 11 minutes and 40 seconds. After cooling, you will get rice bran cookies.

[0057] The quality analysis of the prepared biscuits was performed, and the results are shown in Table 4. The biscuits prepared using the rice bran oil gel of this invention have a 10.6% lower fat content and a 2.0% higher dietary fiber content compared to butter biscuits. The hardness is slightly increased, the chewiness is reduced, and the texture is crisper. Sensory evaluation shows that the rice bran oil gel biscuits have a similar appearance and flavor to butter biscuits, and are highly acceptable to consumers.

[0058] Table 4 Comparison of biscuit quality with different fat matrices

[0059] In summary, this invention obtains rice bran oil rich in natural rice bran wax using supercritical fluid extraction technology, and then combines it with a small amount of added gelling agent (especially beeswax). Utilizing the synergistic crystallization effect of the natural rice bran wax and the added gelling agent, a rice bran oil gel with excellent oil-binding capacity, high antioxidant activity, and good thermal stability is successfully constructed. This gel can completely replace butter in baked goods, significantly reducing the product's fat content and increasing its dietary fiber content, while maintaining excellent sensory quality, demonstrating promising application prospects.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rice bran oil gel, characterized in that, It consists of rice bran oil rich in natural rice bran wax and an added gelling agent; The rice bran oil rich in natural bran wax is extracted directly from rice bran using supercritical fluid extraction technology, and the mass percentage of natural bran wax in the rice bran oil is 0.5% to 3%. The added gelling agent is at least one of beeswax or monoglyceride, and its addition amount is 6% to 10% of the mass of rice bran oil; The rice bran oil gel has a three-dimensional network structure formed by the co-crystallization of natural rice bran wax and an added gelling agent, with an oil binding capacity of ≥95% and DPPH free radical scavenging rate and ABTS free radical scavenging rate of ≥95%.

2. The rice bran oil gel according to claim 1, characterized in that, The added gelling agent is beeswax, and its addition amount is 6% to 10% of the mass of rice bran oil.

3. The rice bran oil gel according to claim 1, characterized in that, The added gelling agent comprises beeswax and monoglycerides, with a total addition amount of 6% to 8% of the mass of rice bran oil, wherein the mass ratio of beeswax to monoglycerides is 1:3 to 3:

1.

4. The rice bran oil gel according to any one of claims 1-3, characterized in that, The supercritical fluid extraction technology is supercritical CO2 extraction, and its extraction conditions include: extraction temperature 45℃~55℃, extraction time 1.5h~2.5h, and extraction pressure 25MPa~35MPa.

5. A method for preparing rice bran oil gel as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Rice bran oil rich in natural bran wax is extracted from rice bran using supercritical fluid extraction technology. The rice bran is stabilized rice bran that has been treated with saturated steam at 121℃ for 15 min to 25 min. S2. Add the external gelling agent to the rice bran oil rich in natural rice bran wax obtained in step S1, and mix to obtain a mixture; S3. Heat the mixture to 80℃~90℃ and stir at a constant temperature until the added gelling agent is completely dissolved to form a uniform and transparent mixed oil. S4. Cool the mixed oil and allow it to stand and crystallize, wherein the standing temperature is 4℃~25℃ and the standing time is 12h~24h, so that it crystallizes and solidifies to obtain the rice bran oil gel.

6. The method according to claim 5, characterized in that, The heating temperature in step S3 is 85℃, and the stirring time is 20min to 30min; the cooling in step S4 is to first let it stand and cool to 45℃, and then let it stand at 4℃ for 18h.

7. The application of rice bran oil gel prepared by the method according to any one of claims 5-6 in the preparation of baked goods, characterized in that, The rice bran oil gel is used as a substitute for butter in the preparation of low-fat baked goods.

8. The application according to claim 7, characterized in that, The low-fat baked goods are biscuits, cakes, or cookies.

9. A rice bran biscuit, characterized in that, The raw materials for preparing the rice bran biscuits include rice bran oil gel as described in any one of claims 1-4, and defatted rice bran obtained by supercritical CO2 extraction of rice bran; the rice bran oil gel completely replaces butter, and the amount of defatted rice bran added is 5% to 15% of the total mass of the biscuit raw materials.

10. The rice bran biscuit according to claim 9, characterized in that, The amount of defatted rice bran added is 8% to 12% of the total raw material mass of the biscuits.

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