A method for making a sprouted brown rice rice bran paste
Patent Information
- Application Number
- CN202510549351.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-29
- Publication Date
- 2026-10-30
AI Technical Summary
[0022]1. 营养增值
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Abstract
Description
Technical Field
[0001] This invention relates to the field of rice bran processing, specifically a method for making sprouted brown rice bran sauce, belonging to the field of agricultural product processing technology. Background Technology
[0002] Brown rice, as a whole grain food, has high nutritional value, including abundant dietary fiber, vitamins, minerals, and bioactive components. However, its coarse texture, hard consistency, and long cooking time limit its widespread use as a staple food. Germination can activate endogenous enzyme systems in brown rice, promoting the breakdown and conversion of starch, protein, and other nutrients, thereby improving its palatability and digestibility. The bran, a byproduct of germinated brown rice, is an important resource, rich in dietary fiber, protein, antioxidants (such as oryzanol and gamma-glutamyl transferase), and minerals, representing a potential high-value food ingredient.
[0003] However, the application of rice bran in food faces multiple challenges. On the one hand, rice bran contains a relatively high amount of anti-nutritional factors (such as phytic acid and tannins), which can affect the body's absorption of minerals. On the other hand, the high fat content and lipase activity in rice bran make it highly susceptible to oxidation and rancidity, producing a "bran taste" that reduces sensory acceptance. In addition, rice bran has a high proportion of insoluble dietary fiber, which may affect the texture and stability of products during food processing. For example, Yin Hewei (2022) found that when rice bran was added to wheat flour to make noodles, the hardness of the noodles increased and the breakage rate increased due to the filling effect of dietary fiber; Hu Si et al. (2021) found that when rice bran powder was used to make bread, the specific volume of the bread first increased and then decreased with the increase of the amount added, and excessive dietary fiber and ash would affect the fermentation of the dough and the quality of the finished product; He Jingying et al. (2022) pointed out that excessive rice bran powder content in rice bran biscuits would lead to a harder texture and darker color, thus affecting sensory evaluation. In addition, the insolubility of rice bran protein and polysaccharides in functional beverages also leads to insufficient beverage stability (Zhang et al., 2015).
[0004] To address the aforementioned shortcomings in rice bran applications, researchers both domestically and internationally have recently attempted to modify and process rice bran using a series of technologies. Stabilization treatment, defatting processes, enzymatic hydrolysis, and fermentation are the main directions. For example, in the 1990s, the United States used rice bran as a functional food ingredient through stabilization treatment, while Japan's Tsukino Fumi Co., Ltd. developed a water-soluble powder made from defatted rice bran for use in food processing. However, these technologies largely focus on addressing the issues of rancidity and anti-nutritional factors in rice bran, failing to simultaneously improve its sensory properties and nutritional functions.
[0005] Solid-state fermentation, as a green bioprocessing method, effectively degrades anti-nutritional factors such as phytic acid and tannins in rice bran through the metabolic action of microorganisms, while generating various beneficial metabolites, such as amino acids, small peptides, and antioxidants, thereby improving the nutritional quality and sensory characteristics of rice bran. Furthermore, the fermentation process can reduce the risk of rancidity in rice bran and improve its storage stability.
[0006] This invention utilizes a combined germination and solid-state fermentation process to prepare a high-protein, high-dietary-fiber germinated brown rice bran paste. Germination activates the endogenous enzyme system in the rice bran, enhancing the activity of its nutrients; solid-state fermentation degrades anti-nutritional factors and improves sensory properties. The purpose of this invention is to overcome the technical bottlenecks in the application of rice bran in the food industry, explore its potential applications in high-value-added functional foods, and provide theoretical basis and technical support for improving resource utilization efficiency and promoting the development of whole-grain foods.
[0007] This study enhances the comprehensive utilization value of rice bran through innovative processes, promotes the efficient conversion of grain resources, and provides new ideas for solving the problems of anti-nutritional factors and sensory characteristics in rice bran applications. It also promotes the research and development of high-nutrition and high-functional foods, contributing to the development of the food industry and the improvement of human health. Summary of the Invention
[0008] To address the aforementioned technical problems, this invention germinates brown rice and uses fungal fermentation to produce a rice bran sauce product. By utilizing germination and solid-state fermentation with soy sauce koji, the nutritional components and flavor of the rice bran are optimized, making it suitable for use in condiment and sauce products.
[0009] This invention is achieved through the following technical solutions:
[0010] The method for making sauce using sprouted brown rice bran includes the following steps:
[0011] Step 1: Germination treatment of brown rice: After washing the brown rice, soak it in a 1% sodium hypochlorite solution for 15 minutes in the dark for disinfection. Then rinse it several times with clean water and place it in a germination tray with a damp gauze. Germinate it in the dark at 25 ℃ for 36 hours, watering it once every 12 hours.
[0012] Step 2: Steam treatment and drying of sprouted brown rice: Steam the sprouted brown rice with 100℃ steam for 5 minutes. After the brown rice cools, dry it using a staged heating method. The air inlet temperature sequence is: 40℃ for 2 hours, 50℃ for 2 hours, and 65℃ until the moisture content of the sprouted brown rice is about 12%.
[0013] Step 3: Milling: The dried germinated brown rice is milled in a blower-type rice milling machine until it reaches 6%, thus obtaining rice bran with the highest nutritional content of the germinated brown rice.
[0014] Step 4: Solid-state fermentation: After stirring the rice bran into a fluffy state, add soy sauce koji at an inoculation rate of 2%. After stirring thoroughly, ferment at a constant temperature of 30°C for 3 days.
[0015] Step 5: Seasoning the Rice Bran Sauce: Select mold-free dried shiitake mushrooms, rinse them, and then soak them in a 50℃ water bath for 3-4 hours. Remove, drain, and dice. Fry the diced mushrooms in oil at 120℃ for 2-3 minutes. Take peanut oil and, at 125℃, add chili powder, diced mushrooms, and rice bran. Then add salt, sugar, and soybean paste, and stir-fry evenly. The weight ratio of peanut oil:dried shiitake mushrooms:chili:sugar:salt:rice bran:soybean paste is 1:1:0.12:0.1:0.01:0.69:0.69.
[0016] Brown rice is a highly nutritious whole grain food, but it suffers from problems such as a rough texture, difficulty in cooking, and lower eating quality. Germination treatment can activate the endogenous enzymes in brown rice, degrading macromolecules and anti-nutritional factors, thereby improving the nutritional value and eating quality of brown rice. Germinated brown rice is often processed using light milling, and its processing byproduct, rice bran, is rich in nutrients and is an agricultural raw material with great development potential. To ensure that the trace elements and various nutrients in rice bran are retained to the greatest extent, the changes in nutritional components of germinated and ungerminated brown rice bran at different milling degrees (2%, 4%, 6%, 8%) were compared. The results showed that germination can significantly increase the content of protein, bound phenols, dietary fiber, and GABA in rice bran, while reducing the content of fat, free phenols, phytic acid, ash, and some heavy metals (As, Cd, and Pb). Among these, the protein and GABA content of rice bran increases with increasing milling degree, while the content of dietary fiber, total phenols, ash, and fat decreases with increasing milling degree. Therefore, the brown rice is first germinated in step one. Since germinated brown rice is more difficult to mill, it needs to be heat-treated in step two to reduce the breakage rate. The study investigated the changes in nutritional and sensory qualities of rice bran fermented by six fungi: soy sauce koji, *Rhizopus oligosporus*, *Aspergillus niger*, *Mucor racemosa*, and *Mucor radiata*. The results showed that all selected fungi significantly increased the protein and soluble dietary fiber content of rice bran while reducing the insoluble dietary fiber and phytic acid content. Among them, rice bran fermented with soy sauce koji had the highest protein and soluble dietary fiber content, and also showed a strong ability to degrade insoluble dietary fiber and phytic acid in germinated brown rice bran. The sensory quality of rice bran was determined using an electronic nose, headspace gas chromatography-ion mobility spectrometry, and an electronic tongue. The results showed that rice bran fermented with soy sauce koji had a pleasant aroma, and its aroma composition was significantly different from other strains. It exhibited the highest variety of identifiable major volatile substances, including two alcohols, three ketones, one aldehyde, one ester, and one pyrazine. Fermentation with soy sauce koji effectively enhanced the acidity, umami, saltiness, and richness of the rice bran, while reducing its bitterness, lingering bitterness, and astringency. Therefore, soy sauce koji was selected as the fermentation strain for rice bran in step five.
[0017] Preferably, in step three, the degree of milling of brown rice is selected using the Sudan III ethanol solution staining method in GB / T5502-2017 "Grain and Oil Inspection - Rice Processing Precision Inspection". Analysis is performed using an individual microscope. Through photographs of the milling precision of germinated brown rice, it was found that most of the bran layer was removed when the milling degree was 2%, and the bran layer at the grooves was almost completely removed when the milling degree was 6%. Compared with the milling degree of 8%, the germ was more clearly preserved. Therefore, a milling degree of 6% is more suitable for the light milling processing of germinated brown rice. So, in step three, the milling degree of brown rice is 6%.
[0018] Preferably, in step four, because an appropriate amount of water is needed during fermentation, and in order to prevent the final rice bran sauce from being too low in concentration, the weight ratio of rice bran to distilled water is chosen to be 1:0.5.
[0019] Preferably, in step five, the solid-state fermentation process of soy sauce koji is optimized. The results show that when the inoculation amount is 2.0%, the culture temperature is 30 ℃, and the fermentation time is 3 days, the degradation rate of phytic acid in rice bran reaches 43.13%, which is the best effect. The inoculation amount of soy sauce koji is selected as 2%, and after thorough stirring, it is fermented at a constant temperature of 30 ℃ for 3 days.
[0020] Preferably, in step seven, response surface methodology is used to optimize the rice bran sauce formulation. The rice bran sauce with the highest sensory score was obtained at the optimal process with 12% chili pepper, 10% sugar, 69% rice bran, and 69% soybean paste. Therefore, the weight ratio of chili pepper:sugar:rice bran:soybean paste is selected as 0.12:0.1:0.69:0.69.
[0021] Compared with the prior art, the present invention has the following advantages and technical effects:
[0022] 1. Nutritional Enhancement
[0023] The combination of germination and fermentation processes significantly enhances the nutritional value of rice bran, particularly the utilization rate of protein, soluble dietary fiber, and minerals, meeting consumers' demand for highly nutritious condiments.
[0024] 2. Degradation of anti-nutritional factors
[0025] Through the fermentation process of soy sauce koji, phytic acid in rice bran is effectively degraded, the content of anti-nutritional factors is reduced, and minerals (such as calcium, iron, zinc, etc.) are more easily absorbed by the human body, thus improving the bioavailability of rice bran sauce.
[0026] 3. Flavor Improvement
[0027] The fermentation process enhances the umami, saltiness, and sourness of the rice bran sauce, while significantly reducing bitterness and astringency, resulting in a rich and layered flavor that makes it suitable for direct consumption as a condiment or dipping sauce.
[0028] 4. Economic and resource utilization value
[0029] This invention transforms rice bran, a byproduct of brown rice, into a nutrient-rich condiment sauce, extending its industrial chain, increasing product added value, and helping to reduce rice bran resource waste, thus aligning with the sustainable development goal of comprehensive resource utilization. Attached Figure Description
[0030] Figure 1 This figure shows the effect of different inoculation amounts on the degradation of phytic acid in rice bran by soy sauce koji.
[0031] Figure 2 The graph shows the effect of different temperatures on the degradation of phytic acid in rice bran by soy sauce koji.
[0032] Figure 3 This is a graph showing the effect of different time points on the degradation of phytic acid in rice bran by soy sauce koji.
[0033] Figure 4 This is a graph showing the effect of the amount of chili pepper added on the sensory score in this invention.
[0034] Figure 5 This is a graph showing the effect of the amount of sugar added on sensory scores in this invention.
[0035] Figure 6 This is a graph showing the effect of the amount of rice bran added on the sensory score in this invention.
[0036] Figure 7 This is a graph showing the effect of the amount of soybean paste added in this invention on the sensory score.
[0037] Figure 8 Sensory rating charts for different rice bran sauces of this invention.
[0038] IV. Specific Implementation Cases
[0039] Example 1: Optimization of fermentation and roasting conditions
[0040] Rice bran was fermented using soy sauce koji. Single-factor experiments were conducted with inoculum size, culture temperature, and fermentation time as individual variables. The optimal conditions for each variable were selected to optimize the conditions for the next variable. Inoculum sizes were 0.5%, 1%, 1.5%, 2%, and 2.5%; culture temperatures were 25 ℃, 28 ℃, 30 ℃, 33 ℃, and 35 ℃; and fermentation times were 1 d, 2 d, 3 d, 4 d, and 5 d. Each treatment was repeated three times.
[0041] For the production of rice bran sauce, 50 g of mold-free dried shiitake mushrooms are rinsed, then soaked in a 50℃ water bath for 3-4 hours. After draining, the mushrooms are diced and deep-fried at 120℃ for 2-3 minutes. 50 g of peanut oil is heated to 125℃, and chili powder, diced mushrooms, and rice bran are added. Salt, sugar, and soybean paste are then added and stir-fried until well combined.
[0042] Single-factor experimental design: With a fixed salt addition of 1% (compared to shiitake mushrooms), and using fuzzy mathematical sensory evaluation as the indicator, single-factor experiments were conducted with chili pepper addition, sugar addition, rice bran addition, and soybean paste addition as single variables. The chili pepper addition amounts were 8%, 10%, 12%, 14%, and 16%; the sugar addition amounts were 4%, 7%, 10%, 13%, and 15%; the rice bran addition amounts were 50%, 60%, 70%, 80%, and 90%; and the soybean paste addition amounts were 50%, 60%, 70%, 80%, and 90%.
[0043] Response surface methodology: Based on the results of the single-factor experiments, sensory scores were used as the response values. The Box-Behnken Design in DesignExpert 8.06 software was used to optimize the formulation and process of rice bran sauce by selecting the amount of chili added, sugar added, rice bran added, and soybean paste added as factors, with three levels for each factor. The parameters are shown in Table 1.
[0044] Table 1. Response Surface Experiment Factors and Levels
[0045] level A: Chili addition amount / % B: Sugar addition amount / % C: Rice bran addition amount / % D: Soybean paste addition amount / % -1 10 7 60 60 0 12 10 70 70 1 14 13 80 80
[0046] Sensory evaluation: The color, taste, flavor, and texture of the rice bran sauce were used as evaluation indicators (Table 2). Ten food-related students with normal color, taste, and smell abilities were recruited and screened to serve as sensory evaluators. The sensory evaluators did not communicate with each other and did not come into contact with irritating foods before evaluation. After evaluating each sample, they rinsed their mouths with water and waited for 1 minute. The evaluators scored the samples according to the indicators in the table, using four levels: good, relatively good, fair, and poor, on a 100-point scale.
[0047] Table 2 Sensory Evaluation Criteria for Rice Bran Paste
[0048] Table 4-2 Sensory evaluation criteria for rice bran paste
[0049] Total Score Color taste fragrance Organizational status Good (≥80 points) The sauce is glossy. The sweetness is moderate, the umami flavor is strong, and the texture is harmonious. Rich aroma and harmonious flavor Good viscosity Good (60-79 points) The sauce has an oily sheen and uneven color. The sweet and salty flavors are slightly stronger or slightly weaker, and the overall taste is well-balanced. The aroma is weak, the bean paste flavor is strong, and the overall taste is poor. Poor viscosity Average (20-59 points) The sauce has a dull, non-greasy appearance. The flavor is too sweet and salty, lacking umami, resulting in an unbalanced taste. The fragrance is faint, but there is no unpleasant odor. The sauce has poor fluidity. Poor (≤19 points) The sauce has poor shine, and its color is either too light or too dark. Too spicy, too salty, or too sweet; rough texture It has an odor The sauce is very thin.
[0050] The basic nutritional components of rice bran paste are determined as follows:
[0051] Protein content was determined according to GB5009.5-2016 "National Food Safety Standard - Determination of Protein in Food". Dietary fiber was determined according to GB5009.88-2014 "National Food Safety Standard - Determination of Dietary Fiber in Food". Ash content was determined according to GB5009.4-2016 "National Food Safety Standard - Determination of Ash in Food". Fat content was determined according to GB5009.6-2016 "National Food Safety Standard - Determination of Fat in Food".
[0052] Determination of phytic acid: Take 0.5 g of dried rice bran sample, add 30 mL of nitric acid solution (0.5 mol / L), and extract by shaking at 30 ℃ for 4 h. Then, dilute to 50 mL with water, filter, discard the initial filtrate, and collect the filtrate for analysis. Take two 10 mL stoppered colorimetric tubes, add 2.4 mL of 0.5 mol / L nitric acid solution and 0.15 mL of extract to each, respectively. Add 0.6 mL of 0.76 mmol / L ferric ammonium sulfate solution to one tube, and leave the other tube as a blank control. Shake well and boil in a water bath for 20 min. Immediately cool to room temperature under running water. Add 0.2 mL of 10% ammonium thiocyanate solution to each colorimetric tube, shake well, centrifuge at 3000 × g for 10 min, and let stand for 2 min. Measure the absorbance A at 500 nm using a 1 cm cuvette, with the solution from the blank control as the reference solution. A standard curve was prepared using a sodium phytate standard solution. The amount of sodium phytate (μmol) was obtained from the absorbance A, and the phytic acid content in the sample was then calculated.
[0053] GABA determination: Take 1 g of dried rice bran sample, add 10 mL of distilled water, and shake in an air bath at 60 ℃ for 2 h. After shaking, centrifuge at 8000 × g for 10 min. Take 0.5 mL of the supernatant, add 0.2 mL of borate buffer (0.2 mol / L, pH 10.0) and 1 mL of 6% phenol, mix well, add 0.4 mL of NaClO solution in an ice-water bath, place at room temperature for 4-8 min, then in a 60 ℃ water bath for 10 min, and immediately in an ice bath for 10 min. When the solution turns blue-green, add 2.0 mL of 60% ethanol, and measure the absorbance at 645 nm.
[0054] The degradation of phytic acid by soy sauce koji at 30 ℃ for 3 days under different inoculum amounts is shown in the attached figure. Figure 1 As shown, different inoculum amounts have a certain impact on the degree of phytic acid degradation in rice bran fermented with soy sauce koji. When the inoculum amount is between 0.5% and 2.0%, the ability of soy sauce koji to degrade phytic acid increases with increasing inoculum amount. Furthermore, the phytic acid content in the rice bran is lowest at an inoculum amount of 2.0%, at 43.64 mg / g. When the inoculum amount exceeds 2.0%, the ability of soy sauce koji to degrade phytic acid actually decreases. This may be because the nutrients in the substrate are insufficient to support excessive fungal growth, thus reducing the activity of the fungi and decreasing their ability to produce phytase.
[0055] Appendix Figure 2The figure shows the degradation of phytic acid by soy sauce koji at different fermentation temperatures under different conditions, with an inoculum amount of 2% and a fermentation period of 3 days. As can be seen from the figure, the phytic acid content in rice bran first decreases and then increases with the increase of fermentation temperature. The phytic acid content in rice bran reaches the lowest level at 30 ℃, which is 43.92 mg / g. This indicates that the fermentation of soy sauce koji has a better ability to degrade phytic acid in rice bran at 30 ℃.
[0056] Appendix Figure 3 The data shows the degradation of phytic acid by soy sauce koji at an inoculum amount of 2% and a fermentation temperature of 30 ℃ for different fermentation times. During fermentation times of 1–3 days, the phytic acid content in rice bran decreased with increasing fermentation time, reaching its lowest level of 44.28 mg / g at 3 days. When the fermentation time exceeded 3 days, there was no significant difference in the phytic acid content of rice bran. This may be due to the limitation of nutrients such as carbon, nitrogen, and water in the culture medium. As the fermentation time increases, the microbial strain enters a decline phase, with reduced growth activity and enzyme production capacity, preventing further degradation of phytic acid in the rice bran. Therefore, a fermentation time of 3 days is considered appropriate. Ten sensory evaluators evaluated the single-factor samples. Taking the first group of samples with the single-factor rice bran addition amount as an example, the results are shown in Table 3.
[0057] Table 3 Sensory Rating Table
[0058]
[0059] Appendix Figure 4 The figure shows the sensory evaluation results after varying the amount of chili added, with fixed sugar (10%), rice bran (70%), and soybean paste (70%) additions. As the chili addition increases from 8% to 12%, the sensory score of the rice bran sauce continuously rises. At 8% chili addition, the rice bran sauce has a darker color, less pronounced spiciness, and a slightly stronger sweet and salty flavor. The sensory score is highest at 12% chili addition, with a bright red color and moderate spiciness. The sensory score continuously decreases as the chili addition increases from 12% to 16%. Excessive chili addition can lead to an overly numbing and spicy rice bran sauce, and the chili itself is relatively coarse, resulting in a poorer texture and a heavy grainy feel when chewing. Therefore, the chili addition amounts selected for the response surface methodology were 10%, 12%, and 14%.
[0060] Appendix Figure 5The results show the sensory evaluation results after varying the sugar addition, with fixed amounts of chili pepper (10%), rice bran (70%), and soybean paste (70%). When the sugar addition increased from 4% to 10%, the sensory score of the rice bran paste consistently rose. This is because sugar undergoes the Maillard reaction at high temperatures, producing a caramelized brown color, and also enhances umami flavor. Therefore, at 4% sugar addition, the rice bran paste exhibited a noticeable sour taste due to fermentation, a lighter color, and poorer flavor. At 10% sugar addition, the rice bran paste had a bright, glossy color, a balanced sweet and spicy flavor, and the highest sensory score. When the sugar addition increased from 10% to 16%, the sensory score consistently declined. Excessive sugar addition resulted in an overly dark color, an overly sweet taste, and masked the paste's unique flavor, leading to a poor sensory score. Response surface methodology should consider sugar addition amounts of 7%, 10%, and 13%.
[0061] Appendix Figure 6 The figure shows the sensory evaluation results after varying the amount of rice bran added, while keeping the chili pepper addition at 10%, sugar addition at 10%, and soybean paste addition at 70%. As the figure shows, the sensory score of the rice bran sauce continuously increased as the rice bran addition increased from 50% to 70%. When the rice bran addition was only 50%, the sourness of the sauce was not obvious, and the overall sweet and spicy flavor was relatively strong. Furthermore, because the rice bran, after fermentation with soy sauce koji, had a dark brown color similar to beef sauce, it had a good appearance. Therefore, when the rice bran addition was low, the sauce was too light in color, thin, and uneven. When the rice bran addition was 70%, the color of the rice bran sauce reached a balance, the fermented flavor of the rice bran was well-coordinated with the sweet and spicy flavor, the sauce was thick and uniform, and the overall score was the highest. When the amount of rice bran added increased from 70% to 90%, the sensory score of the rice bran sauce continued to decline. When the amount of rice bran added was 90%, the rice bran sauce had a strong sour taste, a dark color, a thick and viscous consistency, and poor fluidity. In addition, because rice bran contains a lot of insoluble dietary fiber, when too much rice bran is added, the product will have a rough texture, a strong fibrous feel, and more residue after chewing. Therefore, its sensory score is low. Thus, the response surface methodology experiment selected rice bran addition amounts of 60%, 70%, and 80%.
[0062] Appendix Figure 7The results show the sensory evaluation after varying the amount of soybean paste added, with fixed amounts of chili (10%), sugar (10%), and rice bran (70%). Soybean paste significantly affected the color, flavor, texture, and consistency of the rice bran sauce. Sensory scores gradually decreased as the amount of soybean paste increased from 50% to 70%. At 50% soybean paste, the sauce was lighter in color, less viscous, had a strong sour and spicy flavor from the rice bran, and poor umami. The highest sensory score was achieved at 70% soybean paste; at this level, the sauce was bright in color, uniformly viscous, did not mask the unique flavor of the fermented rice bran, and had a balanced sweet and salty taste. As the amount of soybean paste added increased, its sensory evaluation score gradually decreased. This was because adding too much soybean paste made the rice bran sauce saltier, darker in color, and too viscous, resulting in a poor overall texture. Furthermore, the flavor of the soybean paste masked the aroma of shiitake mushrooms and fermented rice bran, leading to a decrease in the overall score of the sauce. Therefore, the response surface methodology experiment selected soybean paste addition amounts of 60%, 70%, and 80%.
[0063] Example 2: Response Surface Optimization of Rice Bran Paste Formulation
[0064] The experiment used four factors as single factors: the amount of chili added, the amount of sugar added, the amount of rice bran added, and the amount of soybean paste added, and the fuzzy mathematical sensory rating as the response surface value, in a Box-Behnken combined design experiment (Table 4).
[0065] Table 4 Response Surface Experimental Design and Results
[0066] Number Factor 1A: Amount of chili peppers added Factor 2B: Sugar Addition Factor 3C: Rice bran addition amount Factor 4D: Soybean Paste Addition Amount Sensory score (sense rating / point) 1 -1 -1 0 0 73.07 2 1 -1 0 0 64.07 3 -1 1 0 0 70.71 4 1 1 0 0 71.7 5 0 0 -1 -1 73.77 6 0 0 1 -1 76.35 7 0 0 -1 1 77.11 8 0 0 1 1 65.64 9 -1 0 0 -1 69.22 10 1 0 0 -1 75.64 11 -1 0 0 1 72.07 12 1 0 0 1 67.48 13 0 -1 -1 0 65.67 14 0 1 -1 0 73.29 15 0 -1 1 0 71.13 16 0 1 1 0 68.35 17 -1 0 -1 0 72.81 18 1 0 -1 0 75.26 19 -1 0 1 0 74.74 20 1 0 1 0 64.26 21 0 -1 0 -1 72.96 22 0 1 0 -1 72.24 23 0 -1 0 1 67.3 24 0 1 0 1 73.97 25 0 0 0 0 82.72 26 0 0 0 0 83.18 27 0 0 0 0 83.06 28 0 0 0 0 81.53 29 0 0 0 0 84.74
[0067] Table 5 shows that the model p-value < 0.0001, indicating a highly significant difference. The p-value for the lack-of-fit term = 0.1409 > 0.05, indicating no significant difference. This suggests that there is a linear relationship between the sensory score (Y) of rice bran sauce and the amounts of chili added (A), sugar added (B), rice bran added (C), and soybean paste added (D). The model is statistically significant, and the obtained quadratic multinomial regression equation is: Y = 83.05 - 1.18A + 1.34B - 1.45C - 1.38D + 2.50AB - 3.23AC - 2.75AD - 2.60BC + 1.85BD - 3.51CD - 6.34A 2 -7.17B 2 -5.43C 2 -4.75D 2 Adj R 2=0.8991 is the adjusted coefficient of determination for the regression model, indicating that the model can explain 89.91% of the changes in the response values. The model has a good fit and small error, so optimizing the amounts of chili, sugar, rice bran, and soybean paste to improve the sensory score of rice bran sauce is feasible. The results show that items A, B, C, D, AB, and BC have a significant impact on the sensory score (p<0.05), while items AC, AD, CD, and A have a significant impact (p<0.05). 2 B 2 C 2 D 2 The effect of this item on sensory ratings was highly significant (p < 0.01). Taking the first partial derivative of the regression equation to zero further confirms the value of the optimal point, resulting in the following formula:
[0068] -1.18+2.50B-3.23C-2.75D-12.68A=0 (1)
[0069] 1.34+2.50A-2.60C+1.85D-14.34B=0 (2)
[0070] -1.45-3.23A-2.60B-3.51D-10.86C=0 (3)
[0071] -1.38-2.75A+1.85B-3.51C-9.50D=0 (4)
[0072] The optimal combination of processes was determined to be 11.95% chili pepper, 10.31% sugar, 68.72% rice bran, and 69.29% soybean paste. Under these conditions, the theoretical sensory score of the rice bran paste could reach 83.28 points.
[0073] To verify the effectiveness of the response surface methodology, an optimal combination experiment was conducted using 12% chili pepper, 10% sugar, 69% rice bran, and 69% soybean paste. The resulting sensory score was 82.76, which differed from the theoretical value predicted by the model by 0.52 points. This indicates that the model is feasible for optimizing the rice bran paste processing technology and has practical value.
[0074] Table 5. Analysis of Variance for Regression Models
[0075] Source of variance Square sum Degrees of freedomFreedom degrees Mean squares sum F value P-value Model 881.06 14 62.93 18.83 < 0.0001 A 16.83 1 16.83 5.03 0.0415 B 21.49 1 21.49 6.43 0.0238 C 25.35 1 25.35 7.58 0.0155 D 22.99 1 22.99 6.88 0.0201 AB 24.95 1 24.95 7.46 0.0162 AC 41.80 1 41.80 12.50 0.0033 AD 30.31 1 30.31 9.07 0.0093 BC 27.04 1 27.04 8.09 0.0130 BD 13.65 1 13.65 4.08 0.0628 CD 49.35 1 49.35 14.77 0.0018 <![CDATA[A 2 ]]> 261.11 1 261.11 78.12 < 0.0001 <![CDATA[B 2 ]]> 333.08 1 333.08 99.65 < 0.0001 <![CDATA[C 2 ]]> 190.97 1 190.97 57.13 < 0.0001 <![CDATA[D 2 ]]> 146.64 1 146.64 43.87 < 0.0001 residual 46.79 14 3.34 Missing item 41.50 10 4.15 3.14 0.1409 Pure error 5.29 4 1.32 Total deviation 927.85 28
[0076] Table 6 Basic Nutritional Components of Rice Bran Paste
[0077] type protein% Moisture% Ash content % Fat% Dietary fiber % Sprouted fermented rice bran sauce 7.68±0.52a 23.05±0.52a 4.13±0.05b 36.90±0.80a 13.95±0.12a Unsprouted fermented rice bran sauce 6.82±0.09b 23.15±0.50a 5.06±0.48a 37.09±0.67a 11.41±0.22c Unsprouted and unfermented rice bran paste 6.03±0.20b 24.88±0.18a 4.47±0.03ab 36.95±0.43a 12.30±0.14b
[0078] Table 6 shows that the basic nutritional components of rice bran paste differed under different treatments. Sprouted and fermented rice bran paste had the highest protein content, which increased by 12.61% and 27.36% compared to unsprouted and unfermented rice bran paste, respectively. There were no significant differences in moisture and fat content among the three types of rice bran paste. However, unsprouted and fermented rice bran paste had the highest ash content, which was significantly different from that of sprouted and fermented rice bran paste. The sprouted and fermented rice bran paste had the highest dietary fiber content, which increased by 22.26% and 13.41% compared to the other two treatments, respectively.
[0079] From the appendix Figure 8 It can be seen that there is no significant difference in the sensory scores between sprouted and unsprouted rice bran sauce, indicating that sprouting treatment does not change the overall flavor of rice bran sauce. However, the sensory quality of unsprouted rice bran sauce is significantly higher than that of unsprouted and unfermented rice bran sauce, indicating that fermenting rice bran with soy sauce koji can significantly improve the flavor quality of rice bran sauce.
[0080] The changes in nutritional composition of different rice bran sauces are mainly related to the different treatments of rice bran. Germinated fermented rice bran sauce has the highest protein content. This is partly because germination increases the crude protein content of the rice bran, and partly because solid-state fermentation by fungi, due to nitrogen concentration, also increases the crude protein content of the substrate, consistent with previous conclusions. Although fungi consume some water for growth and metabolism during fermentation, the moisture content of the substrate itself is not high, so the changes in the rice bran sauce are not significant. The fat content is relatively low because a large amount of oil is added during sauce preparation, while the fat consumed during germination and metabolism is relatively small, resulting in no significant changes in moisture and fat content across the three treatments. Ungerminated fermented rice bran sauce has the highest ash content. This is because some inorganic salts are lost with the soaking liquid after germination, and the weight of the substrate decreases after fermentation, leading to a corresponding increase in ash content. The highest dietary fiber content in sprouted and fermented rice bran paste is due to the significant increase in total dietary fiber content caused by the sprouting process. Although fermentation reduces some insoluble dietary fiber content, it does not significantly reduce the total dietary fiber content compared to the increase during sprouting. Furthermore, the increase in dietary fiber in sprouted rice bran does not significantly reduce the sensory quality of the rice bran paste.
Claims
1. A method for preparing sprouted brown rice bran paste, characterized in that, This includes optimizing fermentation conditions, optimizing the rice bran paste formula, and preparing the rice bran paste. The specific steps are as follows: A. Optimization of fermentation culture conditions The following design utilizes soy sauce koji to ferment rice bran: Single-factor experiments were conducted with inoculum size, culture temperature, and fermentation time as individual variables. The optimal conditions for each variable were selected to optimize the conditions for the next variable. The inoculum size of soy sauce koji was 0.5%, 1%, 1.5%, 2%, and 2.5%; the culture temperature was 25 ℃, 28 ℃, 30 ℃, 33 ℃, and 35 ℃; and the fermentation time was 1 d, 2 d, 3 d, 4 d, and 5 d. Each treatment was repeated three times. The results showed that when the inoculum amount of soy sauce koji was 2.0%, the culture temperature was 30℃, and the fermentation time was 3 days, the phytic acid degradation rate in rice bran was the highest, decreasing to 44.28 mg / g. B. Rice bran paste recipe optimization Rinse 50g of dried shiitake mushrooms that are free of mold. Then soak the cleaned shiitake mushrooms in a 50℃ water bath for 3-4 hours. Remove, drain, and dice. Fry the diced shiitake mushrooms in oil at 120℃ for 2-3 minutes. Take 50g of peanut oil and add chili powder, diced shiitake mushrooms, and rice bran at 125℃. Then add salt, white sugar, and soybean paste and stir-fry evenly. Single-factor experimental design: With the salt addition fixed at 1% of the shiitake mushrooms, and using fuzzy mathematical sensory evaluation as the indicator, single-factor experiments were conducted with the addition of chili peppers, sugar, rice bran, and soybean paste as single variables. The chili pepper addition amounts were 8%, 10%, 12%, 14%, and 16%; the sugar addition amounts were 4%, 7%, 10%, 13%, and 15%; the rice bran addition amounts were 50%, 60%, 70%, 80%, and 90%; and the soybean paste addition amounts were 50%, 60%, 70%, 80%, and 90%. Response surface methodology: Based on the results of the single-factor experiments, using sensory scores as the response values, Box-Behnken Design was adopted, with the amount of chili added, the amount of sugar added, the amount of rice bran added, and the amount of soybean paste added as factors. Three levels were selected for each factor to optimize the formulation and process of rice bran paste. The results showed that the rice bran sauce with the highest sensory score was made with the base formula of 50g dried shiitake mushrooms, 1% salt, 50g peanut oil, 12% chili peppers, 10% sugar, 69% rice bran, and 69% soybean paste. C. Making Rice Bran Paste Germination treatment of brown rice: After washing the brown rice, soak it in a 1% sodium hypochlorite solution for 15 minutes in the dark for disinfection. Then rinse it several times with clean water and place it in a germination tray with a damp gauze. Germinate it in the dark at 25℃ for 36 hours, watering it once every 12 hours. Steam treatment and drying of germinated brown rice: Germinated brown rice was steamed at 100℃ for 5 minutes. After the brown rice cooled, it was dried using a staged heating method. The air inlet temperature was sequentially 40℃ for 2 hours, 50℃ for 2 hours, and 65℃ until the moisture content of the germinated brown rice was 12%. Milling: The dried germinated brown rice is milled in a rice milling machine with a milling degree of 6%; Solid-state fermentation: After stirring the rice bran into a fluffy state, add soy sauce koji at an inoculation rate of 2%, stir thoroughly, and ferment at a constant temperature of 30℃ for 3 days; Rice bran sauce recipe: Select mold-free dried shiitake mushrooms, rinse them, then soak the cleaned shiitake mushrooms in a 50℃ water bath for 3-4 hours, remove, drain, and dice. Fry the diced shiitake mushrooms in oil at 120℃ for 2-3 minutes. Take peanut oil, and at 125℃, add chili powder, diced shiitake mushrooms, and rice bran. Then add salt, white sugar, and soybean paste and stir-fry evenly. The weight ratio of peanut oil:dried shiitake mushrooms:chili:sugar:salt:rice bran:soybean paste is 1:1:0.12:0.1:0.01:0.69:0.
69. The results showed that the protein content and dietary fiber content of the germinated fermented rice bran paste were 7.68% and 13.95%, respectively.
2. The method for preparing sprouted brown rice bran paste according to claim 1, characterized in that, In step C, during the germination treatment of brown rice, water is sprayed and the gauze is replaced every 12 hours to maintain suitable humidity and ventilation conditions, ensuring germination effect and hygiene.
3. The method for preparing sprouted brown rice bran paste according to claim 1, characterized in that, In step C, during the steam treatment and drying of the germinated brown rice, the germinated brown rice is heated in 100°C steam for 5 minutes to reduce the rate of cracking, and then dried at 40°C, 50°C, and 65°C for 2 hours, 2 hours, and until the moisture content is 12%.
4. The method for preparing sprouted brown rice bran paste according to claim 1, characterized in that, In step C, the milling process involves controlling the milling time to achieve the maximum milling degree, where the germ of the sprouted brown rice is retained. The milling degree is controlled at 6%, preserving the germ and main nutrients of the sprouted rice bran while removing some coarse fiber, thus improving the texture and taste of the rice bran paste. The formula for calculating abrasiveness is: A(%) = (1 - Ai / A0) × 100 In the formula: A represents the degree of milling, %; A0 represents the weight of the raw rice, g; A i This indicates the weight of the rice grains after milling, expressed in grams (g).
5. The method for preparing sprouted brown rice bran paste according to claim 1, characterized in that, In step C, the fermentation conditions used in the solid-state fermentation process are soy sauce koji. The protein content of the fermented rice bran increased by 16% compared to the unfermented rice bran, and its soluble dietary fiber increased by 45%. At the same time, the phytic acid degradation rate reached 43.13% during the fermentation process.
6. The method for preparing sprouted brown rice bran paste according to claim 1, characterized in that, In step C, the rice bran sauce formula was optimized using response surface methodology. By controlling the levels of different variables and analyzing their impact on product characteristics, the formula ratio was optimized to achieve the best balance between nutrition and sensory appeal. Optimization factors included: chili pepper addition, sugar addition, rice bran addition, and soybean paste addition. The response variables mainly include: protein content, dietary fiber content, and sensory score.