A High-Functional Defatted Rice Bran, Its Preparation Method and Application

Abstract

This invention discloses a high-functionality defatted rice bran, its preparation method, and its applications. The method includes: stabilizing fresh rice bran with saturated steam to inactivate lipase, obtaining stabilized rice bran; then using the stabilized rice bran as raw material, extracting and defatting it with supercritical CO2 to separate rice bran oil and high-functionality defatted rice bran. Preferably, the saturated steam treatment temperature is 115-125℃, and the time is 15-25 min; the supercritical CO2 extraction temperature is 45-55℃, the pressure is 25-35 MPa, and the time is 1.5-2.5 h. The defatted rice bran prepared by this invention has a fat content of less than 1.5%, a water-holding capacity of more than 3.0 g / g, an oil-holding capacity of more than 2.4 g / g, and an expansion potential of more than 5.8 g / g. This method is green and environmentally friendly, significantly improving the functional properties of defatted rice bran. The resulting product can be used as a high-dietary-fiber ingredient in baked goods, showing good application prospects.

Description

Technical Field

[0001] This invention relates to the fields of agricultural product processing and food engineering technology, and in particular to a high-functionality defatted rice bran, its preparation method, and its application. Background Technology

[0002] Rice bran is a major byproduct of rice processing, accounting for approximately 10%-12% of the weight of rice. It is rich in oil (15%-20%), high-quality protein, dietary fiber, vitamins, and natural antioxidants (such as oryzanol and tocopherol), and has various health benefits such as regulating blood lipids and anti-oxidation. It is a valuable resource for developing modern fortified foods and functional foods.

[0003] However, the high-value utilization of rice bran has long been limited by its highly susceptible nature to rancidity and spoilage. Rice bran contains highly active lipases and lipoxygenases. During the rice milling process, these enzymes come into contact with the oils in the rice bran, rapidly catalyzing the hydrolysis of the oils into free fatty acids, which then oxidize and become rancid, resulting in unpleasant flavors, reduced nutritional value, and an extremely short shelf life. Therefore, timely and effective stabilization treatment of fresh rice bran to inactivate the lipases is a crucial prerequisite for the resource utilization of rice bran.

[0004] Currently, common rice bran stabilization technologies mainly include dry heat treatment, microwave treatment, and extrusion treatment. Dry heat treatment (such as roasting) involves high temperatures (120-160℃), which can inactivate enzymes but may destroy heat-sensitive nutrients (such as proteins and vitamins). Microwave treatment is highly efficient, but requires large equipment investments and results in uneven processing. Extrusion puffing can inactivate enzymes but may alter the physicochemical properties of rice bran. These common rice bran stabilization technologies cannot effectively improve the utilization rate of components such as oil and dietary fiber in rice bran. Furthermore, to further utilize the oil and protein resources in rice bran, the stabilized rice bran is usually degreased. Traditional pressing or organic solvent extraction methods suffer from low oil extraction efficiency, organic solvent residues, and environmental pollution. Moreover, the high-temperature treatment process may further damage the functional components such as protein and dietary fiber in defatted rice bran (cake), significantly reducing its application value.

[0005] Therefore, developing a green and environmentally friendly technology that can efficiently inactivate enzymes, gently defatt the rice, and retain and enhance the functional properties of rice bran to the maximum extent is of great significance for promoting the high-value utilization of rice bran. Summary of the Invention

[0006] To address the shortcomings of existing rice bran processing technologies, such as poor enzyme inactivation, safety and environmental hazards in degreasing processes, high residual oil content in degreased rice bran, and unsatisfactory functional properties, this invention provides a method for preparing highly functional degreased rice bran using supercritical CO2 extraction. This method achieves efficient enzyme inactivation, structural disruption, and green degreasing of rice bran through the efficient coupling of saturated steam stabilization and supercritical CO2 extraction, while significantly improving the core functional properties of degreased rice bran, such as water retention, oil retention, and swelling potential. This is because saturated steam treatment loosens the rice bran structure, significantly increasing supercritical CO2 permeability and degreasing efficiency, and drastically reducing the residual oil content. The synergistic effect of the efficient coupling of saturated steam stabilization and supercritical CO2 extraction results in significantly superior functional properties (water retention, oil retention, and swelling potential) compared to traditional processes. This invention also provides the highly functional degreased rice bran prepared by this method and its applications in the food industry.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing highly functional defatted rice bran includes the following steps: S1. Fresh rice bran is subjected to saturated steam stabilization treatment. This process serves two purposes: first, it inactivates the lipases in the rice bran, resulting in stabilized rice bran; second, it disrupts the cell structure of the rice bran, improves its functional properties, and facilitates the extraction of oil components from the rice bran. S2. Using the stabilized rice bran as raw material, supercritical CO2 is used for extraction and degreasing to separate rice bran oil and high-functionality degreased rice bran.

[0008] Preferably, in step S1, the saturated steam treatment temperature is 115–125°C, and the treatment time is 15–25 min. More preferably, the temperature is 121°C, and the time is 20 min. Under these conditions, the activity of rice bran lipase can be reduced from approximately 79.71 mg / g to approximately 19.87 mg / g, significantly extending the storage stability of rice bran.

[0009] Preferably, in step S2, the supercritical CO2 extraction conditions are: extraction temperature 45–55℃, extraction pressure 25–35 MPa, and extraction time 1.5–2.5 h. More preferably, the extraction temperature is 50℃, the extraction pressure is 30 MPa, and the extraction time is 2 h. Under these conditions, the oil extraction efficiency of rice bran can reach over 94.15%, and the residual oil rate of defatted rice bran is less than 1.2%.

[0010] Preferably, before step S1, a pretreatment step of sieving and removing impurities from the fresh rice bran is included.

[0011] Preferably, in step S2, the supercritical CO2 extraction adopts a dynamic extraction mode, and the flow rate of the CO2 fluid is controlled at 20-30 L / h.

[0012] Preferably, after step S2, a post-processing step is included to desolventize, dry, and pulverize the extracted defatted rice bran crude product.

[0013] Preferably, the solvent removal process employs vacuum drying with a vacuum degree of -0.08 to -0.09 MPa and a drying temperature of 45 to 50°C.

[0014] The present invention also protects the high-functionality defatted rice bran prepared according to any one of the above methods, wherein the fat content is 1.0% to 1.5%, the water holding capacity is 3.0 to 5.0 g / g, the oil holding capacity is 2.0 to 4.0 g / g, and the swelling potential is 5.0 to 7.0 g / g.

[0015] Preferably, the high-functional defatted rice bran has a fat content of 1.14±0.13%, a water holding capacity of 3.08±0.08 g / g, an oil holding capacity of 2.43±0.05 g / g, and an expansion potential of 5.82±0.23 g / g.

[0016] This invention further protects the application of the high-functional defatted rice bran in the preparation of high-dietary-fiber baked goods or functional grain foods.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. Excellent enzyme inactivation effect and strong storage stability: The rice bran lipase can be quickly and completely inactivated by precise treatment with saturated steam at 115-125℃. The stabilized rice bran after treatment can be stored at 35℃ for 30 days without significant deterioration in quality. 2. Green and environmentally friendly process, high product safety: Supercritical CO2 extraction is used for degreasing. CO2 is non-toxic, odorless, and leaves no residue. It can be recycled and there is no risk of solvent residue. The degreased rice bran prepared meets food-grade safety standards. 3. High degreasing efficiency and excellent product functional characteristics: The finished degreased rice bran has a fat content of less than 1.5%, and its water-holding capacity, oil-holding capacity, and swelling potential are significantly better than those of degreased rice bran prepared by traditional methods; 4. Highly efficient process coupling and strong applicability: Suitable for large-scale industrial production, the high-functionality defatted rice bran prepared can be widely used in baking and grain food fields, greatly improving the economic added value of rice bran resources. Attached Figure Description

[0018] Figure 1 The images shown are scanning electron microscope (SEM) images of rice bran with different treatments in Example 1 of the present invention; where Ct is untreated rice bran, Zq is saturated steam stabilized rice bran, and Zq-SFE is high-functional defatted rice bran treated by the method of the present invention. Figure 2This is a comparison diagram of the hydration properties of rice bran treated with different methods in Example 2 of the present invention; where A represents water retention, B represents oil retention, C represents swelling potential, and D represents water solubility index. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Example 1 S1. Rice Bran Pretreatment and Stabilization: Fresh rice bran was passed through a 40-mesh sieve to remove impurities. The sieved rice bran was weighed and placed in a vertical pressure steam sterilizer, treated with saturated steam at 121℃ for 20 minutes to obtain stabilized rice bran (Zq). The lipase activity of fresh rice bran was determined to be 79.71±6.35 mg / g, which decreased to 19.87±1.06 mg / g after treatment.

[0021] S2. Supercritical CO2 Extraction Degreasing: Weigh 200g of stabilized rice bran and place it into the 1L extraction vessel of the supercritical CO2 extraction apparatus. Set the extraction temperature to 50℃, the extraction pressure to 30MPa, and the CO2 flow rate to 25L / h, and perform dynamic extraction for 2 hours. Collect the rice bran oil and remove the defatted rice bran.

[0022] S3. Post-processing: The defatted rice bran was placed in a vacuum drying oven and dried for 2 hours under a vacuum of -0.085 MPa and a temperature of 50℃. After pulverizing and sieving, high-functionality defatted rice bran (Zq-SFE) was obtained. The calculated oil extraction efficiency was 94.15%, and the residual oil rate was 1.14 ± 0.13%.

[0023] Example 2 The performance of Zq-SFE prepared in Example 1 was characterized, with untreated rice bran (Ct) and stabilized rice bran (Zq) as controls.

[0024] like Figure 1 As shown, the microstructure analysis (SEM) results reveal that the Zq-SFE surface exhibits numerous cracks and pores, exposing the fiber network structure, which provides the structural basis for its excellent hydration properties.

[0025] like Figure 2 As shown in the figure, the functional characteristics analysis results show that the water holding capacity of Zq-SFE is 3.08±0.08 g / g, the oil holding capacity is 2.43±0.05 g / g, and the expansion potential is 5.82±0.23 g / g, all of which are significantly better than the control group.

[0026] Example 3 The Zq-SFE prepared in Example 1 was added to shortbread biscuits at proportions of 0%, 5%, 10%, 15%, and 20%. The results showed that when 10% was added, the dietary fiber content of the biscuits was significantly increased, and the texture and sensory scores were optimal.

[0027] Example 4 This embodiment is basically the same as Embodiment 1, except that: in step S1, the saturated steam treatment temperature is 115℃ and the treatment time is 25min; in step S2, the supercritical CO2 extraction temperature is 45℃, the extraction pressure is 25MPa, the extraction time is 2.5h, and the CO2 flow rate is 20L / h.

[0028] Example 5 This embodiment is basically the same as Embodiment 1, except that: in step S1, the saturated steam treatment temperature is 125℃ and the treatment time is 15min; in step S2, the supercritical CO2 extraction temperature is 55℃, the extraction pressure is 35MPa, the extraction time is 1.5h, and the CO2 flow rate is 30L / h.

[0029] Comparative Example 1 Rice bran was stabilized by treating it with dry hot air at 140℃ for 60 minutes, and then degreased by extraction with hexane organic solvent. The remaining post-treatment steps were the same as in Example 1, and conventional degreased rice bran was prepared.

[0030] Performance testing The defatted rice bran prepared in Examples 1, 4, and 5 and Comparative Example 1 were tested for key indicators, and the results are shown in the table below: Table 1. Core Indicator Testing Table

[0031] As shown in the table, the defatted rice bran prepared by the method of the present invention is significantly better than that of Comparative Example 1 in terms of fat content, water retention, oil retention and swelling potential, which verifies the feasibility and superiority of the technical solution of the present invention.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various improvements and modifications without departing from the spirit and principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing highly functional defatted rice bran, characterized in that, Includes the following steps: S1. Fresh rice bran is subjected to saturated steam stabilization treatment to inactivate the lipase in it, thereby obtaining stabilized rice bran; S2. Using the stabilized rice bran as raw material, supercritical CO2 is used for extraction and degreasing to separate rice bran oil and high-functionality degreased rice bran.

2. The method according to claim 1, characterized in that, In step S1, the temperature of the saturated steam treatment is 115-125°C, and the treatment time is 15-25 min.

3. The method according to claim 1, characterized in that, In step S2, the conditions for supercritical CO2 extraction are: extraction temperature 45-55℃, extraction pressure 25-35MPa, and extraction time 1.5-2.5h.

4. The method according to claim 1, characterized in that, Before step S1, there is also a pretreatment step of sieving and removing impurities from the fresh rice bran.

5. The method according to claim 1, characterized in that, In step S2, the supercritical CO2 extraction adopts a dynamic extraction mode, and the flow rate of the CO2 fluid is controlled at 20-30 L / h.

6. The method according to claim 1, characterized in that, After step S2, there are also post-processing steps of desolventizing, drying and pulverizing the crude defatted rice bran obtained by extraction.

7. The method according to claim 6, characterized in that, The solvent removal process employs vacuum drying with a vacuum degree of -0.08 to -0.09 MPa and a drying temperature of 45 to 50°C.

8. The high-functionality defatted rice bran prepared by the method according to any one of claims 1 to 7, characterized in that, Its fat content is 1.0% to 1.5%, water holding capacity is 3.0 to 5.0 g / g, oil holding capacity is 2.0 to 4.0 g / g, and swelling potential is 5.0 to 7.0 g / g.

9. The high-functionality defatted rice bran according to claim 8, characterized in that, Its fat content is 1.14±0.13%, water holding capacity is 3.08±0.08 g / g, oil holding capacity is 2.43±0.05 g / g, and swelling potential is 5.82±0.23 g / g.

10. The use of the high-functional defatted rice bran according to claim 8 or 9 in the preparation of high-dietary-fiber baked goods or functional grain foods.

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