A method for preparing a dietary fiber-enriched and high-antioxidant wine lees

Abstract

This invention relates to a method for preparing a rice wine rich in dietary fiber and high antioxidant properties, belonging to the field of agricultural product deep processing technology. The method is characterized by using glutinous rice as the raw material and rice bran as an auxiliary material. The rice bran is extruded, puffed, and ultra-finely pulverized, then mixed with glutinous rice at a mass ratio of 4-8%. The mixture undergoes processes such as steaming, cooling, mixing with koji (fermentation starter), fermentation, filtration, and sterilization to produce a rice wine with a total dietary fiber content of 1064 mg / 100g, a soluble dietary fiber content of 331 mg / 100g, a DPPH scavenging rate of 93.2%, and a sensory evaluation score of 91.5. The novel rice wine provided by this invention has a high soluble dietary fiber content, significantly enhanced in vitro antioxidant capacity, excellent taste and flavor, and is simple to operate and easily scalable for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of agricultural product deep processing technology, specifically relating to a method for preparing rice wine rich in dietary fiber and high antioxidants. Background Technology

[0002] Fermented glutinous rice, a traditional Chinese specialty, is beloved for its sweet and mellow flavor and rich nutritional value. Traditional fermented glutinous rice is primarily made from glutinous rice through microbial fermentation, containing various amino acids and B vitamins. However, with changing market demands, the limitations of traditional fermented glutinous rice products in terms of flavor, nutritional function, and product form have become increasingly apparent, making it difficult to meet the needs of modern consumers. Although the rice wine industry has developed rapidly in recent years, the problem of relatively limited product variety remains prominent. Therefore, researchers have begun to explore the use of diversified raw materials to expand the flavor and nutritional value of fermented glutinous rice, such as using plant-based raw materials like kudzu root, codonopsis, and colored sweet glutinous corn for innovative development. Related research has made some progress; for example, patent CN202410519379.0 proposes a compound fermented fruit and vegetable fermented glutinous rice beverage and its preparation method, while patent CN202310846430.4 proposes a cinnamon fermented glutinous rice with antioxidant functions and its preparation method.

[0003] Rice bran is an important byproduct of rice processing, formed from milled brown rice. Its main components include the seed coat, pericarp, aleurone layer, nucellus, and embryo. Rice bran contains over 50% of the nutrients found in rice and is characterized by low allergenicity, rich nutrition, and diverse functions. Brown rice retains the outer bran (composed of rice bran, etc.), which is rich in dietary fiber and various bioactive components. For example, patent CN201811135684.0 uses germination and exogenous enzyme treatment combined with Rhizopus oryzae fermentation technology to produce brown rice wine with a unique taste. However, in actual production, when directly fermenting brown rice to produce wine, the surface bran forms a physical barrier that hinders the utilization of starch by the yeast, reducing the alcohol yield and resulting in a low sugar-acid ratio, poor taste, and low consumer acceptance.

[0004] This invention proposes a method for preparing brown rice wine rich in dietary fiber, possessing strong antioxidant properties, a suitable sugar-acid ratio, and a pleasant taste by exogenously adding rice bran. Simultaneously, extrusion puffing and ultrafine grinding technologies are combined to further enhance the processing adaptability and functional properties of rice bran. Extrusion puffing, as an efficient food processing method, can break the glycosidic bonds between rice bran fiber molecules, increasing the solubility of insoluble dietary fiber, while simultaneously deactivating lipases in rice bran, reducing the risk of rancidity, and thus extending its shelf life. Furthermore, this technology can effectively improve the physical properties of rice bran and enhance its utilization rate during the fermentation process. On the other hand, ultrafine grinding technology can further reduce the particle size of rice bran, improve its dispersibility, and make it easier for microorganisms to degrade and utilize during fermentation, thereby optimizing the product's taste and texture. Therefore, this study aims to improve the quality of rice bran-rich rice wine through the synergistic effect of extrusion puffing and ultrafine grinding technologies, in order to promote the diversification of rice wine products and meet the modern consumer demand for healthy foods. Summary of the Invention

[0005] Technical problem: The purpose of this invention is to provide a method for preparing rice wine rich in dietary fiber and high antioxidants, which solves the problems of limited variety of rice wine products on the market and low sugar-acid ratio and low fermentation efficiency in direct fermentation of brown rice wine.

[0006] Technical Solution: A method for preparing fermented rice rich in dietary fiber and high antioxidants involves using high-quality glutinous rice as the main raw material. The glutinous rice is washed and impurities are removed, then soaked in water at 20-30℃ for 10-24 hours until it can be easily crushed by hand. Rice bran is used as an auxiliary material. The rice bran is mixed with water at a mass ratio of 18-24%, and stirred in a mixer for 30-60 minutes. The mixture is then fed at a constant speed into a twin-screw extruder, where it is extruded using a four-stage heating program. The resulting extruded product is dried at 40-60℃ and then ultra-finely pulverized to obtain pretreated rice bran.

[0007] Glutinous rice and extruded rice bran are mixed in a ratio of 92% to 96% of the total mass of glutinous rice and 4% to 8% of the total mass of rice bran. The mixture is then steamed, cooled, mixed with yeast, placed in a fermentation trough, fermented, and sterilized to obtain the finished wine.

[0008] In one embodiment, the constant-rate feeding frequency is 16~20Hz.

[0009] In one embodiment, the twin-screw rotation speed is set to 24~25Hz.

[0010] In one embodiment, the four-stage heating program is as follows: the first stage temperature is 50~60℃, the second stage temperature is 80~90℃, the third stage temperature is 100~110℃, and the fourth stage temperature is 120~130℃.

[0011] In one embodiment, the particle size of the extruded puffed rice bran obtained after ultrafine pulverization is <100 μm.

[0012] In one embodiment, the steaming process involves mixing glutinous rice and distilled water at a ratio of 100-120 mL of distilled water per 150 g of glutinous rice, and then steaming at normal pressure for 30-60 minutes.

[0013] In one embodiment, the cooling process involves spreading the product out to cool it down to 25-30°C.

[0014] In one embodiment, the mixing, fermentation, and fermentation processes involve adding 0.4% to 0.6% by mass of a sweet wine starter containing Aspergillus oryzae, Saccharomyces bayanus, and Streptococcus thermophilus as the main microorganisms. After mixing, the starter is gathered, compacted, and a depression is pressed into the center. The starter is then placed in a constant temperature incubator at 28 to 35°C for 48 to 72 hours for fermentation.

[0015] In one embodiment, the method involves sterilizing the product by holding it in a water bath at 85-95°C for 10-15 minutes, and then cooling it to obtain the finished sweet rice wine.

[0016] In one embodiment, the finished product has a high dietary fiber content of 1064 mg g / 100g; good palatability with a moderate sugar-acid ratio of 45.5; strong in vitro antioxidant capacity with a DPPH scavenging rate of 93.2%; rich flavor, rich in esters, alcohols, aldehydes, ketones, and aromatic compounds, with a high content of aromatic substances, and a sensory score of 91.5.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following advantages: (1) The brown rice wine prepared by the present invention has a moderate sweetness and sourness, good palatability, mellow aroma, good taste and flavor, and a natural grain fermentation aroma. (2) The present invention can effectively solve the inhibitory effect of the bran layer on the fermentation process when directly fermenting brown rice by adding rice bran, and improve the problems of low wine yield, low sugar-acid ratio and poor sensory quality of the product when directly fermenting brown rice. (3) The present invention uses extrusion puffing and ultra-fine grinding as technical means to pretreat rice bran. The lipid content of the extruded puffed rice bran is significantly lower than that of the unextruded puffed rice bran, as low as 14.6g / 100g, which can effectively improve the storage quality of rice bran and prevent oxidation and rancidity of rice bran wine during storage. Meanwhile, after extrusion puffing and ultra-fine grinding, the soluble dietary fiber content in rice bran increases, the release of antioxidants such as polyphenols increases, and the product particle size is <100 μm, which helps to form a rice wine product with high dietary fiber content, good antioxidant effect and delicate taste. (4) By adding exogenous rice bran pretreated by extrusion puffing and ultra-fine grinding, the total dietary fiber content in the rice bran rice wine can reach up to 1064mg / 100g, the soluble dietary fiber content can reach 331mg / 100g, the types and contents of volatile flavor substances increase, the DPPH scavenging rate reaches 93.2%, the product sugar-acid ratio is moderate, and the sensory score reaches 91.5. Attached Figure Description Figure 1 The results are based on the total dietary fiber content, soluble dietary fiber content, DPPH scavenging ability, and sensory scores of different types of fermented rice (white rice represents fermented rice made from refined white glutinous rice; brown rice represents fermented rice made from brown glutinous rice; white rice + rice bran represents fermented rice made from refined white glutinous rice and extruded rice bran).

[0018] Specific implementation methods

[0019] The technical solution of the present invention will be described in detail below with reference to specific embodiments, but the scope of protection claimed by the present invention is not limited to the scope described in the embodiments.

[0020] Method for determining the dietary fiber content of sweet fermented rice: After vacuum freeze-drying and pulverizing, the content of soluble dietary fiber (SDF), insoluble dietary fiber (IDF), and total dietary fiber (TDF) is determined according to the enzymatic hydrolysis gravimetric method specified in national standard GB / T5009.5-2016.

[0021] Methods for determining the in vitro antioxidant capacity of sweet fermented rice: The in vitro antioxidant capacity of sweet fermented rice was characterized by its DPPH scavenging rate and ferric ion reducing ability. The sweet fermented rice was centrifuged at 5000 r / min for 10 min, and the supernatant was collected for later use.

[0022] DPPH scavenging rate determination: 200 μL of sample was mixed with 3.8 mL of 60 μmol / L DPPH-ethanol solution, and the mixture was reacted in a light-shielded environment at 25℃ for 60 min. The absorbance was measured at a wavelength of 517 nm. The DPPH scavenging rate was calculated using the following formula: DPPH clearance rate (%) = (A0 - (A1 - A2)) / A0 In the formula: A0 is the absorbance value after the reaction of ethanol with DPPH; A1 is the absorbance value after the reaction of the sample with DPPH; A2 is the absorbance value after the sample is mixed with ethanol.

[0023] The sensory evaluation method for sweet fermented rice wine was as follows: the original fermented rice wine was diluted 1:1 with deionized water, and the evaluation team consisted of 10 trained sensory evaluators who conducted sensory evaluations on the sweet fermented rice wine samples. The sensory evaluation criteria are shown in Table 1.

[0024] Table 1 Sensory Evaluation Standards for Sweet Fermented Rice Detailed Implementation

[0025] Example 1 High-quality glutinous rice is washed and impurities removed, then soaked in water at 20-30℃ for 10-24 hours until it can be easily crushed by hand. The rice bran is mixed with 18% water by weight and stirred in a mixer for 30 minutes. It is then fed into a twin-screw extruder at a constant speed of 16Hz, with the screw speed set to 24Hz. Extrusion is performed using a four-stage heating program: 50℃, 80℃, 100℃, and 120℃. The resulting extruded product is dried at 40℃, ultra-finely pulverized, and passed through a 150-mesh sieve to obtain extruded rice bran. (The text then repeats the process of adding glutinous rice and extruded rice bran.) Rice bran was mixed at a mass ratio of 96:4 and steamed under normal pressure for 30 minutes until the glutinous rice fully absorbed water and gelatinized. The steamed mixture was then spread out to cool to 25°C, and mixed with 100mL of distilled water per 150g of glutinous rice. 0.4% (w / w) of sweet rice yeast was added and mixed thoroughly. The mixture was then gathered and compacted, with a depression pressed into the center. The mixture was placed in a constant temperature incubator and fermented at 28°C for 72 hours. The resulting fermented rice wine was then sealed in a container, kept in an 85°C water bath for 15 minutes, and then cooled to obtain the finished product. The final product had a total dietary fiber content of 874mg / 100g, a soluble dietary fiber content of 280mg / 100g, a DPPH scavenging rate of 90.7%, and a sensory evaluation score of 86.5.

[0026] Example 2 High-quality glutinous rice is washed and impurity removed, then soaked in water at 20-30℃ for 10-24 hours until it can be easily crushed by hand. Rice bran is mixed with 20% water by weight and stirred in a mixer for 40 minutes. It is then fed into a twin-screw extruder at a constant speed of 18Hz, with the screw speed set to 24Hz. Extrusion is performed using a four-stage heating program: 55℃, 85℃, 105℃, and 125℃. The resulting extruded product is dried at 50℃, ultra-finely pulverized, and passed through a 150-mesh sieve to obtain extruded rice bran. Glutinous rice and extruded rice bran are processed according to a 9... After mixing the glutinous rice and distilling the rice at a mass ratio of 2:8, steam for 40 minutes under normal pressure until the rice fully absorbs water and gelatinizes. After steaming, spread the mixture to cool to 25-30℃, then mix it with 110mL of distilled water per 150g of glutinous rice. Add 0.5% (w / w) of sweet rice yeast and purified water, and mix well. Gather the mixture, compact it, and press a depression in the center. Place the mixture in a constant temperature incubator and ferment at 30℃ for 60 hours. Seal the fermented rice in a container, maintain it in a 95℃ water bath for 10 minutes, and then cool it to obtain the finished product. The final product has a total dietary fiber content of 1064mg / 100g, a soluble dietary fiber content of 331mg / 100g, a DPPH scavenging rate of 93.2%, and a sensory evaluation score of 91.5.

[0027] Example 3 High-quality glutinous rice is washed and impurity removed, then soaked in 25℃ water for 10-24 hours until it can be easily crushed by hand. Rice bran is mixed with water at a mass ratio of 24%, stirred in a mixer for 60 minutes, and fed into a twin-screw extruder at a constant speed of 20Hz. The screw speed is set to 25Hz, and extrusion is performed using a four-stage heating program: 60℃, 90℃, 110℃, and 130℃. The resulting extruded product is dried at 60℃, ultra-finely pulverized, and passed through a 150-mesh sieve to obtain extruded rice bran. The glutinous rice and extruded rice bran are mixed at a ratio of 9:4. After mixing the ingredients at a mass ratio of 6, steam them under normal pressure for 60 minutes until the glutinous rice fully absorbs water and gelatinizes. After steaming, spread the mixture to cool to 25-30℃, then mix it with 120mL of distilled water per 150g of glutinous rice. Add 0.6% (w / w) of sweet yeast and purified water, and mix well. Gather the mixture and compact it, pressing a depression in the center. Place the mixture in a constant temperature incubator and ferment at 35℃ for 48 hours. Seal the fermented rice wine in a container, maintain it in a 90℃ water bath for 10 minutes, and then cool it to obtain the finished product. The total dietary fiber content of the finished product is 963mg / 100g, the soluble dietary fiber content is 293mg / 100g, the DPPH scavenging rate is 91.5%, and the sensory evaluation score is 88.5 points.

[0028] Comparative Example 1 High-quality glutinous rice is washed and cleaned, then soaked in water at 20-30℃ for 10-24 hours until it can be easily crushed by hand. The glutinous rice and rice bran are mixed at a mass ratio of 96:4 and steamed under normal pressure for 30 minutes until the glutinous rice fully absorbs water and gelatinizes. After the steamed mixture is cooled to 25℃, it is mixed with 100mL of distilled water at a ratio of 150g of glutinous rice to 100mL of distilled water, and 0.4% (by mass) of sweet wine yeast is added and mixed well. The mixture is then compacted, and a depression is pressed into the center. The mixture is placed in a constant temperature incubator and fermented at 28℃ for 72 hours. The resulting fermented rice wine is then sealed in a container, kept in an 85℃ water bath for 15 minutes, and then cooled to obtain the finished product. The total dietary fiber content of the finished product is 671mg / 100g, the soluble dietary fiber content is 103mg / 100g, the DPPH scavenging rate is 85.3%, and the sensory evaluation score is 83.5.

[0029] Comparative Example 2 High-quality glutinous rice is washed and impurities removed, then soaked in water at 20-30℃ for 10-24 hours until it can be easily crushed by hand. The glutinous rice and rice bran are mixed at a mass ratio of 92:8 and steamed under normal pressure for 40 minutes until the glutinous rice fully absorbs water and gelatinizes. The steamed mixture is then spread out to cool to 25-30℃, and mixed with 110mL of distilled water per 150g of glutinous rice. 0.5% (w / w) of sweet yeast and purified water are added and mixed well. The mixture is then compacted, with a depression pressed into the center. The mixture is placed in a constant temperature incubator and fermented at 30℃ for 60 hours. The resulting fermented rice wine is then sealed in a container, kept in a 95℃ water bath for 10 minutes, and then cooled to obtain the finished product. The final product has a total dietary fiber content of 764mg / 100g, a soluble dietary fiber content of 131mg / 100g, a DPPH scavenging rate of 86.2%, and a sensory evaluation score of 85.5.

[0030] Comparative Example 3 High-quality glutinous rice is washed and impurities removed, then soaked in water at 25℃ for 10-24 hours until it can be easily crushed by hand. The glutinous rice and rice bran are mixed at a mass ratio of 94:6 and steamed under normal pressure for 60 minutes until the glutinous rice fully absorbs water and gelatinizes. The steamed mixture is then spread out to cool to 25-30℃, and mixed with 120mL of distilled water per 150g of glutinous rice. 0.6% (w / w) of sweet yeast and purified water are added and mixed well. The mixture is then compacted, with a depression pressed into the center. The mixture is placed in a constant temperature incubator and fermented at 35℃ for 48 hours. The resulting fermented rice wine is then sealed in a container, kept in a 90℃ water bath for 10 minutes, and then cooled to obtain the finished product. The final product has a total dietary fiber content of 803mg / 100g, a soluble dietary fiber content of 104mg / 100g, a DPPH scavenging rate of 84.5%, and a sensory evaluation score of 84.5.

[0031] Comparative Example 4 High-quality glutinous rice is washed and cleaned, then soaked in water at 20-30℃ for 10-24 hours until it can be easily crushed by hand. Without adding rice bran, it is directly steamed under normal pressure for 40 minutes until the glutinous rice fully absorbs water and gelatinizes. After the steamed mixture is cooled to 25-30℃, it is mixed with 110mL of distilled water at a ratio of 150g glutinous rice to 150g rice, along with 0.5% (w / w) of sweet yeast and purified water, and mixed well. The mixture is then compacted, and a depression is pressed into the center. The mixture is placed in a constant temperature incubator and fermented at 30℃ for 60 hours. The resulting fermented rice wine is then placed in a sealed container, kept in a 95℃ water bath for 10 minutes, and then cooled to obtain the finished product. The total dietary fiber content of the finished product is 683mg / 100g, the soluble dietary fiber content is 53mg / 100g, the DPPH scavenging rate is 80.3%, and the sensory evaluation score is 73.5 points.

[0032] Comparative Example 5 High-quality brown glutinous rice is washed and cleaned, then soaked in water at 20-30℃ for 10-24 hours until it can be easily crushed by hand. It is then steamed under normal pressure for 40 minutes until the rice fully absorbs water and gelatinizes. After the steamed mixture is cooled to 25-30℃, it is mixed with 110mL of distilled water at a ratio of 150g of glutinous rice to 150g of rice. 0.5% (w / w) of sweet yeast and purified water are added and mixed well. The mixture is then compacted and a depression is pressed into the center. The mixture is placed in a constant temperature incubator and fermented at 30℃ for 60 hours. The resulting fermented rice wine is then sealed in a container, kept in a 95℃ water bath for 10 minutes, and then cooled to obtain the finished product. The total dietary fiber content of the finished product is 183mg / 100g, the soluble dietary fiber content is 37mg / 100g, the DPPH scavenging rate is 63.2%, and the sensory evaluation score is 79.5 points.

[0033] Table 2 Quality results of different examples and comparative examples of fermented rice Total dietary fiber content (mg / 100 g) Water-soluble dietary fiber content (mg / 100 g) DPPH clearance rate (%) Sensory rating Example 1 874 280 90.7% 86.5 Example 2 1064 331 93.2% 91.5 Example 3 963 293 91.5% 88.5 Comparative Example 1 671 103 85.3% 83.5 Comparative Example 2 764 131 86.2% 85.5 Comparative Example 3 803 104 84.5% 84.5 Comparative Example 4 683 53 80.3% 73.5 Comparative Example 5 183 37 63.2% 79.5

Claims

1. A method for preparing a rice wine rich in dietary fiber and high antioxidants, characterized in that... include: S1. Raw material pretreatment: High-quality glutinous rice is used as the main raw material. After washing and removing impurities, the glutinous rice is soaked in water at 20~30℃ for 10~24 hours until it can be crushed by hand. S2. Auxiliary material pretreatment: Rice bran is used as an auxiliary material. After mixing rice bran with water at a mass ratio of 18-24%, it is stirred in a mixer for 30-60 minutes and fed into a twin-screw extruder at a constant speed. The extrusion is carried out using a four-stage heating program. The resulting extruded product is dried at 40-60℃ and then pulverized into ultrafine powder to obtain pretreated rice bran. S3. Steaming: Mix glutinous rice and extruded rice bran at a ratio of 92% to 96% of the total mass of glutinous rice and 4% to 8% of the total mass of rice bran. Then steam under normal pressure for 30 to 60 minutes to ensure that the glutinous rice fully absorbs water and gelatinizes. S4. Mixing the starter culture: After the mixture obtained in S3 is cooled to 25~30℃, pure water and 0.4%~0.6% (by mass) of Aspergillus oryzae (the main microorganism) are added. Aspergillus oryzae ), low-fermentation-power yeast ( Saccharomyces bayanus ) and Streptococcus thermophilus ( Streptococcus thermophilus Mix the sweet wine yeast with water. S5, Building a depression: Gather and compact the mixture obtained in S4, and press a depression in the center of it; S6, Saccharification and fermentation: Place the mixture obtained from S5 into a constant temperature incubator and ferment at 28~35℃ for 48~72h. S7. Sterilization: Place the fermented rice wine obtained from saccharification and fermentation in a sealed container, keep it in a water bath at 85~95℃ for 10~15 minutes, and then cool it to obtain a finished fermented rice wine product rich in dietary fiber.

2. The method for pretreatment of excipients according to claim 1, characterized in that: The four-stage heating program for extrusion puffing is as follows: the first stage temperature is 50~60℃, the second stage temperature is 80~90℃, the third stage temperature is 100~110℃, and the fourth stage temperature is 120~130℃.

3. The method for pretreatment of excipients according to claim 1, characterized in that: The constant-speed feeding frequency for the extrusion puffing is 16~20Hz, and the twin-screw speed is set to 24~25Hz.

4. The method for pretreatment of excipients according to claim 1, characterized in that: The extruded and puffed rice bran obtained after ultrafine grinding has a particle size of < 100 μm.

5. The method according to claim 1, characterized in that: During the mixing process, the ratio of glutinous rice to distilled water is 100-120mL of distilled water per 150g of glutinous rice.

6. The method according to claims 1-7 produces a product with high dietary fiber content, reaching 1064 mg g / 100g; good palatability, with a moderate sugar-acid ratio of 45.5; strong in vitro antioxidant capacity, with a DPPH scavenging rate of 93.2%; rich flavor, rich in esters, alcohols, aldehydes, ketones, and aromatic compounds, with a high content of aromatic substances, and a sensory score of 91.4.

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