High-dispersity germinated brown rice flour rich in bioactive components and preparation method of high-dispersity germinated brown rice flour

Abstract

The invention relates to the technical field of food processing, in particular to high-dispersity germinated brown rice powder rich in bioactive components and a preparation method thereof, and the preparation method comprises the following steps: taking brown rice as a raw material, germinating, baking and carrying out superfine grinding to obtain germinated-baked-superfine ground brown rice powder. Compared with ungerminated brown rice, the germinated brown rice powder prepared by the method has the advantages that the contents of bioactive components gamma-aminobutyric acid, total phenols and total flavonoids are greatly increased, the viscosity is low, the brewing dispersity is good, the anti-aging capability is strong, the stability is high, and the problems that brown rice is poor in taste, low in palatability, difficult to digest and absorb and the like can be effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to highly dispersible germinated brown rice flour rich in bioactive ingredients and a preparation method thereof. Background Art

[0002] Rice is an important food crop, the staple food of more than half of the world's population, and is crucial to human nutrition, energy supply and food security. According to statistics, the world's rice production has reached 481 million tons. Brown rice is the remaining part of rice after husking. Compared with white rice, brown rice contains more nutrients, but has poor cooking effect, rough taste, hard to chew, and limited bioavailability. Currently, its consumer demand is relatively low.

[0003] After soaking brown rice for a period of time under suitable temperature and humidity conditions, its germ growth can be promoted. Germination is a technology that can improve the nutritional content and edible quality of brown rice, and can significantly improve its nutritional value. The germination process usually induces the activation of hydrolases and promotes biochemical reactions, thereby increasing the level of bioactive substances, such as γ-aminobutyric acid, γ-oryzanol, glutathione, phenolic compounds, dietary fiber, vitamins and minerals, etc. It has the functions of detoxification, enhancing immunity, lowering blood sugar, protecting nerves, improving memory, anti-cancer and preventing cardiovascular diseases, etc., and has attracted much attention in recent years.

[0004] Rice noodle products have the advantages of smooth taste, convenient eating and easy to carry. The nutritious rice noodles processed by traditional technology have problems such as high viscosity, poor digestion, poor dispersibility and stability. They contain a large amount of insoluble crude fiber, poor palatability and relatively simple nutrition. The development of nutritious rice noodles with cereals by combining multiple technologies is the future development trend of the instant rice noodles market. Summary of the invention

[0005] In view of the problems existing in the traditional process technology, the present invention provides a highly dispersible germinated brown rice powder rich in bioactive ingredients and a preparation method thereof.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] The present invention provides a method for preparing highly dispersible germinated brown rice flour rich in bioactive ingredients, comprising the following steps:

[0008] The method comprises the following steps: using brown rice as a raw material, removing impurities, washing, disinfecting, soaking, germinating, drying and storing to obtain germinated brown rice. Using germinated brown rice as a raw material, the germinated brown rice is processed by a baking technology, and the germinated brown rice is baked at 120° C. for 10, 20 or 30 minutes, preferably 20 minutes; and after baking, ultrafine grinding is performed to obtain brown rice powder with 60-120 mesh, 120-180 mesh, 180-240 mesh or 240-300 mesh, and preferably, the brown rice powder with a grinding mesh number of 180-240 mesh is obtained.

[0009] The soaking temperature is 30-40°C, preferably 35-40°C; the soaking time is 4-12h, preferably 8-12h; the concentration of the calcium chloride solution is 2-4mmol / L, preferably 3-4mmol / L, optimally 3.0-3.1mmol / L; the germination temperature is 25-35°C, preferably 25-30°C, optimally 29-30°C; the germination time is 12-36h, preferably 24-36h, optimally 24-25h.

[0010] The beneficial effects of adopting the above technical scheme include: compared with ungerminated brown rice, the germinated brown rice prepared by the above method has significantly increased content of bioactive components γ-aminobutyric acid, total phenols, and total flavonoids, while reduced content of protein, starch, fat and phytic acid. The germinated brown rice prepared by the present invention is obtained by baking technology and ultrafine grinding technology to obtain the germinated-baked brown rice, which has the advantages of low viscosity, good dispersibility in dispersing, strong anti-aging ability and high stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is the effect of soaking temperature on the content of bioactive substances in germinated brown rice; Figure 2 is the effect of soaking time on the content of bioactive substances in germinated brown rice; Figure 3 is the effect of calcium chloride solution concentration on the content of bioactive substances in germinated brown rice; Figure 4 is the effect of germination temperature on the content of bioactive substances in germinated brown rice; Figure 5 is the effect of germination time on the content of bioactive substances in germinated brown rice; Figure 6 are the contour plots and response surface plots of γ-aminobutyric acid content (R1); Figure 7 are the contour plots and response surface plots of total phenol content (R2);

[0012] Figure 8 are the contour plots and response surface plots of total flavonoids content (R3); Fig. 9 It is a comparative analysis of the basic nutrients and bioactive components of brown rice before and after germination; Fig.10 is the effect of roasting on the basic nutrients and bioactive components of germinated brown rice; Fig.11 is the effect of roasting on the volatile flavor compounds of germinated brown rice; Fig.12 is the effect of roasting on the gelatinization properties of germinated brown rice; Fig.13 is the effect of roasting on the rheological properties of germinated brown rice; Fig.14 is the effect of ultrafine grinding on the particle size of germinated-roasted brown rice flour; Fig.15 The effect of ultrafine grinding on the basic nutrients and bioactive components of sprouted-roasted brown rice flour; Fig.16 is the effect of ultrafine grinding on the hydration properties of germinated-roasted brown rice flour; Fig.17 The effect of ultrafine grinding on the gelatinization properties of germinated-roasted brown rice flour. DETAILED DESCRIPTION

[0013] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0014] The raw material used in the present invention is brown rice. In order to improve the added value of brown rice and broaden the application of brown rice, the nutritional value of the germinated brown rice is improved by using germination technology, the effects of soaking temperature, soaking time, calcium chloride solution concentration, germination temperature and germination time on the content of γ-aminobutyric acid, total phenol and total flavonoids in the germinated brown rice are studied, and the germination conditions of the germinated brown rice rich in bioactive ingredients are optimized; the baking technology increases the flavor substances of the germinated brown rice; and the ultrafine grinding technology improves the palatability and dispersibility of the germinated brown rice. The results show that the germinated brown rice powder prepared by the present invention has the advantages of good flavor, low viscosity, high dispersibility and the like.

[0015] In the present invention, unless otherwise specified, the experimental reagents and materials of the present invention are all conventional experimental reagents and materials in the art, and can be obtained commercially or prepared by conventional methods. Unless otherwise specified, the experimental methods used in the present invention are all conventional experimental methods in the art.

[0016] In the present invention, the brown rice is purchased from Heilongjiang Wuchang Jinhe Rice Industry Co., Ltd. and is food grade.

[0017] In the present invention, the experimental equipment involved is as follows: a digital display constant temperature water bath, model HH-6, purchased from Shanghai Lichen Bangxi Instrument Technology Co., Ltd.; an electric blast drying oven, model DHG-9145A, purchased from Shanghai Yiheng Scientific Instrument Co., Ltd.; a CNC ultrasonic cleaner, model KQ-250DE, purchased from Kunshan Ultrasonic Instrument Co., Ltd.; an ultraviolet visible spectrophotometer, model UV-5200, purchased from Shanghai Yuanxi Instrument Co., Ltd.; an electric oven, model MG38CB-AA, purchased from Guangdong Midea Kitchen Appliance Manufacturing Co., Ltd.; a high-speed multifunctional pulverizer, model DC-1500A, purchased from Zhejiang Wuyi Dingzang Daily Metal Manufacturing Factory; a gas chromatography-ion mobility spectrometer, model Purchased from GAS Company of Germany; Rapid viscosity tester, model 2194617-TMB, purchased from Perten Instrument Company of Sweden; Rheometer, model MCR302e, purchased from Anton Paar Trading Co., Ltd.; Ultrafine pulverizer, model ST-528, purchased from Ruian Saite Electromechanical Co., Ltd.; Laser particle size analyzer, model Nano-ZS90, purchased from Malvern Instrument Co., Ltd. of the United Kingdom; Collector type constant temperature heating magnetic stirrer, model DF-101S, purchased from Shanghai Lichen Bangsi Instrument Technology Co., Ltd.

[0018] The following is a further introduction through specific embodiments.

[0019] Example 1

[0020] 1.1 Experimental methods

[0021] The preparation method of germinated brown rice comprises the following steps: impurity removal, cleaning, disinfection, soaking, germination, drying and storage. Impurities including immature grains and damaged grains in brown rice are removed, the brown rice is washed with distilled water for 3 times, and is soaked and disinfected with 1% sodium hypochlorite solution for 10 minutes, and then washed and drained with distilled water. Soak the brown rice in a calcium chloride solution of a certain concentration for a certain time under a certain temperature condition, drain the brown rice and evenly spread it on gauze, then cover it with wet gauze, place it in a constant temperature and humidity incubator at a certain temperature, germinate for a certain time under the conditions of darkness and relative humidity of 85%, spray distilled water every 6 hours to keep the brown rice moist, then take the germinated brown rice out of the incubator, place it in a 40°C blast drying oven to dry, and then seal and store the sample in a 4°C refrigerator.

[0022] 1.2 Index analysis and determination methods

[0023] (1) The determination of γ-aminobutyric acid content includes the following steps: crush the sample and pass it through a 100-mesh sieve, accurately weigh 3.0 g of the sample into a 50 mL centrifuge tube, add 30.0 mL of distilled water, extract in a 40°C water bath shaker at a speed of 150 r / min for 2 h, shake on a vortex mixer for 2 min, and centrifuge at 10000 r / min for 5 min. Take 1.0 mL of the supernatant, add 1.0 mL of 0.1 mol / L boric acid buffer (pH 9.0), 1.0 mL of 6% phenol and 2.0 mL of 9% sodium hypochlorite solution, mix well, first boil in water for 10 min, then ice bath for 20 min, until a blue-green color appears, then add 2.0 mL of 60% ethanol, and measure its absorbance at a wavelength of 645 nm. With γ-aminobutyric acid as the standard, a γ-aminobutyric acid standard solution with a mass concentration of 5.0 mg / mL was prepared, 7 colorimetric tubes were taken, and 1.0 mL of 0.00, 0.10, 0.20, 0.40, 0.60, 0.80, and 1.00 mg / mL γ-aminobutyric acid standard solution was added to each of the 7 colorimetric tubes. The absorbance was determined according to the above method, and a regression equation was established with the concentration of the γ-aminobutyric acid standard solution as the abscissa and the absorbance as the ordinate. A standard curve was plotted, and the γ-aminobutyric acid content of the sample was calculated according to the standard curve.

[0024] (2) The determination of total phenol content includes the following steps: crush the sample and pass it through a 100-mesh sieve, accurately weigh 3.0 g of the sample into a 50 mL centrifuge tube, add 30.0 mL of 80% ethanol, extract by ultrasonic at room temperature for 90 min, and centrifuge at 9000 r / min for 5 min. Take 1.0 mL of the supernatant and add it to a 25 mL colorimetric tube, then add 6.0 mL of distilled water and 1.0 mL of Folin phenol reagent, let it stand for 6 min, then add 4.0 mL of 12% sodium carbonate solution, make up to volume with distilled water and shake well, let it stand for 60 min at room temperature, and then measure its absorbance at a wavelength of 760 nm. With gallic acid as the standard, a gallic acid standard solution with a mass concentration of 2.0 mg / mL was prepared. Seven colorimetric tubes were taken, and 1.0 mL of 0.00, 0.01, 0.02, 0.05, 0.10, 0.20, and 0.50 mg / mL gallic acid standard solutions were added to each of the seven colorimetric tubes. The absorbance was determined according to the above method. A regression equation was established with the concentration of the gallic acid standard solution as the abscissa and the absorbance as the ordinate. A standard curve was drawn, and the total phenol content of the sample was calculated according to the standard curve.

[0025] (3) The determination of total flavonoid content includes the following steps: crush the sample and pass it through a 100-mesh sieve, accurately weigh 3.0 g of the sample into a 50 mL centrifuge tube, add 30.0 mL of anhydrous ethanol, extract at room temperature by ultrasonic for 30 min, and centrifuge at 5000 r / min for 5 min. Take 1.0 mL of the supernatant, add 0.3 mL of 5% sodium nitrite solution, shake well and let stand for 5 min, then add 0.3 mL of 10% aluminum nitrate solution, shake well and let stand for 6 min, then add 2.0 mL of 4% sodium hydroxide solution, and dilute to 5 mL with anhydrous ethanol, and measure its absorbance at a wavelength of 510 nm. With rutin as the standard, a rutin standard solution with a mass concentration of 0.4 mg / mL was prepared, 6 colorimetric tubes were taken, 1.0 mL of rutin standard solution with a concentration of 0.00, 0.04, 0.08, 0.12, 0.16, and 0.20 mg / mL were added to each of them, and the absorbance was determined according to the above method. A regression equation was established with the concentration of the rutin standard solution as the abscissa and the absorbance as the ordinate, a standard curve was drawn, and the total flavonoids content of the sample was calculated according to the standard curve.

[0026] (4) Determination of basic nutrients and bioactive components

[0027] Protein content determination: Kjeldahl method, refer to GB 5009.5-2016; fat content determination: Soxhlet extraction method, refer to GB 5009.6-2016; starch content determination: acid hydrolysis method, refer to GB 5009.9-2016; dietary fiber determination: enzyme-weight method, refer to GB 5009.88-2014; reducing sugar content determination: refer to 3,5-dinitrosalicylic acid reagent method; γ-oryzanol content, glutathione content and phytic acid content were determined by γ-oryzanol content kit, reduced glutathione (GSH) content kit and phytic acid content kit, respectively.

[0028] 1.3 Data processing and analysis

[0029] The experimental results are expressed as "mean ± standard deviation", and all experiments were repeated three times under the same conditions. Excel 2016 software was used for data analysis, Design Expert 13.0 software was used to process response surface data, Origin 2024 was used for drawing, and SPSS26.0 was used for variance analysis.

[0030] 1.4 Single factor experimental design and result analysis

[0031] (1) Effect of soaking temperature on the content of bioactive substances in germinated brown rice

[0032] The soaking time of brown rice was fixed at 8h, the concentration of calcium chloride solution was 2mmol / L, the germination temperature was 30℃, and the germination time was 24h. The effects of different soaking temperatures (25, 30, 35, 40 and 45℃) on the contents of γ-aminobutyric acid, total phenols and flavonoids in germinated brown rice were investigated. The results are as follows: Figure 1 As shown, the vertical coordinates from left to right in the figure are the vertical coordinates of γ-aminobutyric acid content, total phenol content, and total flavonoid content.

[0033] Depend on Figure 1 It can be seen that when the soaking temperature is 25-35℃, the content of bioactive ingredients increases with the increase of temperature. When the soaking temperature is 35℃, the γ-aminobutyric acid, total phenols and total flavonoids contents of germinated brown rice reach the maximum values ​​of 1.82, 1.67 and 3.07 mg / g, respectively. When the soaking temperature is higher than 35℃, the contents decrease. This may be because with the increase of soaking temperature, the water absorption rate of brown rice accelerates, and the protein in the embryo produces a large amount of glutamate under the action of proteolytic enzymes, providing a substrate for the synthesis of γ-aminobutyric acid. When the soaking temperature is too high, the activity of glutamate decarboxylase will be inhibited, resulting in a decrease in the production of γ-aminobutyric acid.

[0034] (2) Effect of soaking time on the content of bioactive substances in germinated brown rice

[0035] The soaking temperature of brown rice was fixed at 35℃, the concentration of calcium chloride solution was 2mmol / L, the germination temperature was 30℃, and the germination time was 24h. The effects of different soaking times (0, 4, 8, 12 and 16h) on the contents of γ-aminobutyric acid, total phenols and total flavonoids in germinated brown rice were investigated. The results are as follows: Figure 2 As shown, the vertical coordinates from left to right in the figure are the vertical coordinates of γ-aminobutyric acid content, total phenol content, and total flavonoid content.

[0036] Depend on Figure 2 It can be seen that when the soaking time is 0-8h, the content of bioactive ingredients increases with time. When the soaking time is 8h, the γ-aminobutyric acid, total phenol and total flavonoids contents of germinated brown rice reach maximum values ​​of 1.78, 1.50 and 3.01 mg / g, respectively. When the soaking time exceeds 8h, the contents decrease. This may be because the brown rice is in a water-absorbing state in the early stage of soaking. During the soaking process, the activities of proteolytic enzymes and glutamate decarboxylases in the brown rice are enhanced, which increases the production of γ-aminobutyric acid. When the soaking time exceeds 8h, the water absorption of brown rice reaches saturation, resulting in cell swelling and rupture, and the internal nutrients and active ingredients are gradually dissolved and lost, which reduces the content of γ-aminobutyric acid. At the same time, if the soaking time is too long, the oxygen content in the soaking solution will decrease, which will lead to the massive reproduction of microorganisms, which is not conducive to the germination of brown rice.

[0037] (3) Effect of calcium chloride solution concentration on the content of bioactive substances in germinated brown rice

[0038] The soaking time of brown rice was fixed at 8h, the soaking temperature was 35℃, the germination temperature was 30℃, and the germination time was 24h. The effects of different calcium chloride solution concentrations (0, 1, 2, 3 and 4mmol / L) on the contents of γ-aminobutyric acid, total phenols and flavonoids in germinated brown rice were investigated. The results are as follows: Figure 3 As shown, the vertical coordinates from left to right in the figure are the vertical coordinates of γ-aminobutyric acid content, total phenol content, and total flavonoid content.

[0039] Depend on Figure 3 It can be seen that when the concentration of calcium chloride solution is 0-3mmol / L, the content of bioactive ingredients increases with the increase of concentration. When the concentration of calcium chloride solution is 3mmol / L, the γ-aminobutyric acid, total phenol and total flavonoids contents of germinated brown rice reach the maximum values ​​of 1.83, 1.77 and 3.11mg / g, respectively. When the concentration of calcium chloride solution is higher than 3mmol / L, the contents decrease. This may be because the increase in calcium ion concentration can promote the activity of glutamate decarboxylase, catalyze the decarboxylation of L-glutamate to generate γ-aminobutyric acid, and increase the content of γ-aminobutyric acid. When the calcium ion concentration is too high, it will inhibit the activity of glutamate decarboxylase, thereby reducing the content of γ-aminobutyric acid.

[0040] (4) Effect of germination temperature on the content of bioactive substances in germinated brown rice

[0041] The soaking time of brown rice was fixed at 8h, the soaking temperature was 35℃, the concentration of calcium chloride solution was 2mmol / L, and the germination time was 24h. The effects of different soaking temperatures (20, 25, 30, 35 and 40℃) on the contents of γ-aminobutyric acid, total phenols and flavonoids in germinated brown rice were investigated. The results are as follows: Figure 4 As shown, the vertical coordinates from left to right in the figure are the vertical coordinates of γ-aminobutyric acid content, total phenol content, and total flavonoid content.

[0042] Depend on Figure 4 It can be seen that when the germination temperature is 20-30℃, the content of bioactive ingredients increases with the increase of temperature. When the germination temperature is 30℃, the γ-aminobutyric acid, total phenol and total flavonoids contents of germinated brown rice reach the maximum values ​​of 1.84, 1.71 and 3.09 mg / g, respectively. When the germination temperature is higher than 30℃, the contents decrease. This may be because with the increase of germination temperature, glutamate decarboxylase in brown rice is gradually activated and released, and the enzyme activity is enhanced, which increases the γ-aminobutyric acid content. When the germination temperature is too high, the activity of glutamate decarboxylase is inhibited. Due to the gradual inactivation of the enzyme, the synthesis of γ-aminobutyric acid becomes slow and the content decreases.

[0043] (5) Effect of germination time on the content of bioactive substances in germinated brown rice

[0044] The soaking time of brown rice was fixed at 8h, the soaking temperature was 35℃, the concentration of calcium chloride solution was 2mmol / L, and the germination temperature was 30℃. The effects of different germination times (0, 12, 24, 36 and 48h) on the contents of γ-aminobutyric acid, total phenols and flavonoids in germinated brown rice were investigated. The results are as follows: Figure 5 As shown, the vertical coordinates from left to right in the figure are the vertical coordinates of γ-aminobutyric acid content, total phenol content, and total flavonoid content.

[0045] Depend on Figure 5 It can be seen that when the germination time is 0-24h, the content of bioactive ingredients increases with time. When the germination time is 24h, the γ-aminobutyric acid, total phenol and total flavonoids contents of germinated brown rice reach the maximum values ​​of 1.82, 1.69 and 3.10mg / g respectively. When the germination time exceeds 24h, the content tends to remain unchanged. This may be because with the increase of germination time, protease and glutamate decarboxylase are activated in large quantities, so that protein is hydrolyzed to generate glutamate and glutamate is decarboxylated to generate γ-aminobutyric acid, thereby significantly increasing the γ-aminobutyric acid content; when the germination time is too long, when the accumulation of γ-aminobutyric acid reaches a certain level, it will stimulate the activity of γ-aminobutyric acid transaminase, thereby converting γ-aminobutyric acid into succinic semialdehyde. Moreover, after the germination time is too long, the brown rice is prone to rot, and microorganisms multiply in large numbers, which is not conducive to the germination of brown rice.

[0046] According to the results of the single factor experiment, the optimal parameter range is selected: the soaking temperature is between 30-40°C, preferably 35-40°C; the soaking time is between 4-12h, preferably 8-12h; the concentration of the calcium chloride solution is between 2-4mmol / L, preferably 3-4mmol / L; the germination temperature is between 25-35°C, preferably 25-30°C; the germination time is between 12-36h, preferably 24-36h.

[0047] 1.5 Response surface optimization experimental design and result analysis

[0048] Taking into account the results of the single-factor experiment, according to the Box-Behnken experimental design principle, three factors, namely calcium chloride solution concentration (A), germination temperature (B) and germination time (C), were selected. The γ-aminobutyric acid content (R1), total phenol content (R2) and total flavonoids content (R3) in germinated brown rice were taken as response values. A three-factor three-level response surface optimization experiment was carried out to determine the optimal preparation conditions for germinated brown rice. The experimental results are shown in Table 1.

[0049] Table 1 Box-Behnken experimental design and results

[0050]

[0051] (1) Establishment of regression model for γ-aminobutyric acid content and significance analysis

[0052] The software Design-Expert 13.0 was used to perform quadratic polynomial regression fitting on the experimental results in Table 1, and the quadratic regression model equation of γ-aminobutyric acid content (R1) was obtained: R1 = 1.85 + 0.06A-0.03B + 0.05C-0.08AB + 0.05AC + 0.07BC-0.19A 2 -0.19B 2 -0.25C 2 The results of variance analysis are shown in Table 2.

[0053] Table 2 Regression model and variance analysis of R1

[0054]

[0055]

[0056] Note: ** indicates extremely significant difference (P<0.01); * indicates significant difference (P<0.05)

[0057] As shown in Table 2, the regression model of γ-aminobutyric acid content reached an extremely significant level (P<0.01), and the lack of fit term (P>0.05) was not significant. The coefficient of determination of the regression equation R 2 =0.9883, adjusted determination coefficient R 2 adj = 0.9733, indicating that the regression model has a good fit, the experimental results are reliable, and have statistical significance. 2 , B 2 , C 2 The influence of AB and BC is extremely significant, the influence of B and AC is significant, and the significance of the factors affecting the content of γ-aminobutyric acid is A>C>B, and the significance of the interaction of each factor on the content of γ-aminobutyric acid is AB>BC>AC. The response surface and contour map obtained are shown in Figure 6 As shown, it can be seen that the response surface of the interaction between A and B is convex and has a steep slope, and the contour lines are elliptical and dense, indicating that the interaction between A and B is the largest, which is consistent with the variance analysis in Table 2.

[0058] (2) Establishment of regression model for total phenol content and significance analysis

[0059] The experimental results in Table 1 were fitted with a quadratic polynomial regression using the software Design-Expert 13.0, and the quadratic regression model equation for total phenol content (R2) was obtained: R2 = 1.72 + 0.05A - 0.05B ​​- ​​0.03C - 0.06AB + 0.05AC - 0.04BC - 0.08A 2 -0.20B 2-0.20C 2 The results of variance analysis are shown in Table 3.

[0060] Table 3 Regression model and variance analysis of R2

[0061]

[0062] Note: ** indicates extremely significant difference (P<0.01); * indicates significant difference (P<0.05)

[0063] As shown in Table 3, the regression model of total phenol content reached an extremely significant level (P<0.01), and the lack of fit term (P>0.05) was not significant. The coefficient of determination of the regression equation R 2 =0.9837, adjusted determination coefficient R 2 adj = 0.9628, indicating that the regression model has a good fit, the experimental results are reliable, and have statistical significance. 2 , B 2 , C 2 The influence of C, AB, AC, and BC was significant, and the significance of the factors affecting the total phenol content was A>B>C. The significance of the interaction of each factor on the total phenol content was AB>AC>BC. The response surface and contour map obtained are shown in Figure 7 As shown, the response surface of the interaction between A and B is convex and has a steep slope, and the contour lines are elliptical and dense, indicating that the interaction between A and B is the largest, which is consistent with the variance analysis in Table 3.

[0064] (3) Establishment of regression model for total flavonoid content and significance analysis

[0065] The software Design-Expert 13.0 was used to perform quadratic polynomial regression fitting on the experimental results in Table 1, and the quadratic regression model equation of total flavonoid content (R3) was obtained: R3 = 3.11-0.05A-0.08B+0.07C-0.04AB-0.03AC+0.04BC-0.20A 2 -0.13B 2 -0.15C 2 The results of variance analysis are shown in Table 4.

[0066] Table 4 Regression model and variance analysis of R3

[0067]

[0068] Note: ** indicates extremely significant difference (P<0.01); * indicates significant difference (P<0.05)

[0069] As shown in Table 4, the regression model of total flavonoids content reached an extremely significant level (P<0.01), and the lack of fit term (P>0.05) was not significant. The coefficient of determination of the regression equation R 2 =0.9924, adjusted determination coefficient R 2 adj = 0.9827, indicating that the regression model has a good fit, the experimental results are reliable, and have statistical significance. 2 , B 2 , C 2 The influence of AB, AC, and BC was extremely significant, and the influence of factors affecting the total flavonoid content was significant. The significance of the factors affecting the total flavonoid content was B>C>A, and the significance of the interaction of each factor on the total flavonoid content was BC>AB>AC. The response surface and contour map obtained are shown in Figure 8 As shown, the response surface of the interaction between B and C is convex and has a steep slope, and the contour lines are elliptical and dense, indicating that the interaction between B and C is the largest, which is consistent with the variance analysis in Table 4.

[0070] (4) Determination of optimal conditions and verification of regression model

[0071] The optimal preparation process conditions for germinated brown rice obtained by Design-Expert 13.0 design optimization are: soaking temperature 35℃, soaking time 8h, calcium chloride solution concentration 3mmol / L, germination temperature 30℃, germination time 25h. The established regression model predicts that the γ-aminobutyric acid content is 1.86mg / g, the total phenol content is 1.73mg / g, and the total flavonoid content is 3.12mg / g. After experimental verification, the γ-aminobutyric acid content of the germinated brown rice prepared under the above conditions is 1.84mg / g, the total phenol content is 1.72mg / g, and the total flavonoid content is 3.13mg / g, which is close to the results predicted by the regression model, indicating that the model is highly reliable and has certain feasibility in actual operation.

[0072] 1.6 Comparative analysis of basic nutrients and bioactive components of brown rice before and after germination

[0073] Depend on Fig. 9It can be seen that the protein content of brown rice decreased slightly after germination, which may be due to the enhanced activity of proteolytic enzymes in the early stage of germination, which hydrolyzed the protein into polypeptides or amino acids for synthesis and conversion, resulting in a decrease in protein content; the starch content decreased slightly, and the reducing sugar content increased significantly by 8.95 times (P<0.05). The reason for this phenomenon may be that germination activated the amylase inside the brown rice, hydrolyzed the starch into small molecular sugars such as reducing sugars, and provided energy for the growth of the germ; the fat content decreased slightly, and the γ-oryzanol content increased significantly (P<0.05), which may be because the lipase inside the brown rice was activated during the germination process, which degraded the fat to produce fatty acids and other substances, participated in the glyoxylate cycle during germination, and gradually increased the γ-oryzanol content with the increase of lipase activity; the dietary fiber content increased, which may be due to the fact that amylase and protease hydrolyzed the starch and protein in the bran layer during the germination process, thereby increasing the relative content of dietary fiber. During the germination process, the glutamate decarboxylase in the brown rice is activated, causing the glutamate contained in the rice and the glutamate produced by protein hydrolysis to decarboxylate into γ-aminobutyric acid, which leads to a 4.59-fold increase in the γ-aminobutyric acid content after germination. Various enzymes can be produced through germination to destroy the cell wall and release phenolic substances, thereby increasing the total phenolic content. During the germination process, phenylalanine aminotransferase is gradually activated, and its increased activity is conducive to the synthesis of flavonoids, increasing the total flavonoid content by 8.74 times. Phytic acid usually chelates with minerals such as calcium and magnesium to form insoluble compounds. During the germination process, the phytase in the brown rice is activated, destroying this combination to degrade phytic acid, thereby reducing anti-nutritional properties.

[0074] Example 2

[0075] Taking germinated brown rice as raw material, the basic nutrients, bioactive components, color, volatile flavor substances, gelatinization degree, water solubility index, water absorption index, gelatinization characteristics and rheological properties of germinated brown rice during the baking process were studied, and the optimal baking conditions for germinated brown rice were determined.

[0076] The preparation of germinated-baked brown rice comprises the following steps: in Example 1, the germinated brown rice prepared by soaking temperature of 35° C., soaking time of 8 h, calcium chloride solution concentration of 3 mmol / L, germination temperature of 30° C. and germination time of 25 h, with untreated germinated brown rice as a control group, the germinated brown rice is baked at 120° C. for 10, 20 and 30 min, respectively, and is recorded as GBR, RGBR-10, RGBR-20 and RGBR-30, respectively, and cooled to room temperature.

[0077] 2.1 Experimental methods

[0078] (1) Determination of basic nutrients and bioactive components: The determination method of basic nutrients and bioactive components of germinated brown rice before and after baking is the same as the index analysis determination method in 1.2 of Example 1.

[0079] (2) The color measurement includes the following steps: Use a colorimeter to measure the color of the sample and record the L*, a*, and b* values ​​of the sample. The browning index calculation formula is as follows.

[0080] Browning index = [100(x-0.31)] / 0.172 Formula (1)

[0081] Wherein: x = (a* + 1.75L*) / (5.645L* + a* - 3.012b*).

[0082] Where: L* represents the brightness of the color (0-100), where 0 represents black and 100 represents white; a* represents the red-green color, where positive values ​​represent red and negative values ​​represent green; b* represents the yellow-blue color, where positive values ​​represent yellow and negative values ​​represent blue.

[0083] (3) The determination of volatile flavor substances includes the following steps: using gas chromatography ion mobility spectrometry (GC-IMS) to analyze and detect the main volatile flavor substances of the sample, and establish a volatile component fingerprint. Sample pretreatment conditions: incubation temperature 80°C, incubation time 15min, incubation speed 500r / min. Sample injection conditions: headspace injection needle temperature 85°C, injection volume 0.5mL, cleaning time 30s. Gas chromatography (GC) detection conditions: chromatographic column MXT-5 (15m×0.53mm×1μm), column temperature 60°C, carrier gas is nitrogen (≥99.999%). Carrier gas flow rate program: initial flow rate 1.0mL / min, flow rate linearly increased to 10mL / min within 10min, flow rate linearly increased to 100mL / min within 20min, flow rate linearly increased to 150mL / min within 30min, running time 30min. Ion mobility spectrometry (IMS) detection conditions: drift tube length 5 cm, drift tube temperature 45°C, drift gas is nitrogen (≥99.999%), flow rate 150 mL / min, detector temperature is 45°C.

[0084] (4) Determination of gelatinization degree, water solubility index and water absorption index

[0085] The gelatinization degree determination includes the following steps: accurately weigh 0.2g of sample in a conical flask, add 98.0mL of distilled water, 2.0mL of 10mol / mL potassium hydroxide solution, shake for 2min, centrifuge at 4000r / min for 10min, take 1.0mL of supernatant in a colorimetric tube, add 0.4mL of 0.5mol / mL hydrochloric acid solution, dilute to 10.0mL with water, then add 0.1mL of iodine solution, shake well, measure absorbance at 600nm, and record the measured absorbance as A1. In addition, accurately weigh 0.2g of sample in a conical flask, add 95.0mL of distilled water, 5.0mL of 10mol / mL potassium hydroxide solution, 1.0mL of 0.5mol / mL hydrochloric acid solution, and the other conditions are the same, and the measured absorbance is recorded as A2. The gelatinization degree calculation formula is as follows.

[0086] Gelatinization degree = A 1 / A2×100 formula (2)

[0087] The water solubility index and water absorption index determination include the following steps: accurately weigh 3.0g of sample and place it in a centrifuge tube with constant weight, add 30.0mL of distilled water, stir magnetically for 30min at 50℃, then centrifuge at 4000r / min for 20min, transfer the supernatant into an aluminum box with constant weight, evaporate and dry to constant weight at 105℃. The water solubility index and water absorption index calculation formula are as follows.

[0088] Water solubility index (%) = (m4-m3) / M×100% Formula (3)

[0089] Water absorption index (g / g) = (m2-m1) / M Formula (4)

[0090] In the formula: m1 is the mass of the centrifuge tube at constant weight, g; m2 is the mass of the centrifuge tube containing the precipitate, g; m3 is the mass of the aluminum box at constant weight, g; m4 is the mass of the aluminum box after the supernatant has evaporated, g; M is the mass of the sample, g.

[0091] (5) The determination of gelatinization characteristics includes the following steps: accurately weigh 3.0g of sample and place it in the sample pool, add 25.0mL of distilled water, mix it with the plastic stirrer provided with the instrument, and then test it on the machine. Test procedure: The initial speed is 960r / min, and after 10s, the speed is controlled to 160r / min. First, heat to 50℃ at a rate of 10℃ / min; then, keep at 50℃ for 1min; then, continue to heat the sample to 95℃ at a rate of 12℃ / min and keep it for 2.5min; finally, cool the sample to 50℃ at a rate of 12℃ / min and keep it for 2min. Record all gelatinization parameters, including peak viscosity, trough viscosity, disintegration value, final viscosity, regeneration value and gelatinization temperature.

[0092] (6) The determination of rheological properties includes the following steps: the sample after the gelatinization property determination is taken out and placed on the parallel plates of the rheometer with a diameter of 60 mm, with a fixed spacing of 1 mm, and the edges of the fixtures are coated with silicone oil to prevent water volatilization. Before the measurement, the test temperature is set to 25°C, the sample is balanced on the parallel plates for 2 minutes, and the frequency scanning measurement is performed in the range of 0.1-10 Hz under a constant deformation of 1%, and the changes in the elastic modulus (G'), viscous modulus (G") and loss coefficient (tanδ=G" / G') of the sample during the frequency scanning process are recorded, with a total of 21 detection points.

[0093] 2.2 Data processing and analysis

[0094] The experimental results are expressed as "mean ± standard deviation", and all experiments were repeated three times under the same conditions. Excel 2016 software was used for data analysis, Origin 2024 was used for drawing, and SPSS 26.0 was used for variance analysis.

[0095] 2.3 Experimental results and analysis

[0096] (1) Comparative analysis of basic nutrients and bioactive components: Fig.10 It can be seen that the contents of protein, starch, fat, reducing sugar, γ-aminobutyric acid, total phenols, total flavonoids, γ-oryzanol, glutathione and phytic acid in germinated brown rice decreased after baking (P<0.05), and the dietary fiber content did not change significantly (P>0.05). During the baking process, the protein was denatured and thermally degraded; the starch was partially gelatinized under high temperature conditions; the fat was oxidized and decomposed into raw monoglycerol and free fatty acids; the Maillard reaction occurred between reducing sugars and amino acids; the active ingredients such as γ-aminobutyric acid, total phenols, total flavonoids, γ-oryzanol, glutathione and phytic acid were sensitive to heat, and under the thermal effect of baking treatment, they may be thermally degraded or combined with other macromolecules, resulting in a decrease in content. It can be seen that roasting treatment for 20 minutes can better maintain the basic nutrients and active ingredients in germinated brown rice. Compared with ungerminated brown rice, the contents of γ-aminobutyric acid, total phenols, total flavonoids, γ-oryzanol and glutathione increased by 260.61%, 41.18%, 61.68%, 35.82% and 33.67%, respectively.

[0097] (2) Color analysis: As shown in Table 5, the L* value decreases significantly with the increase of baking time, and the L* value of RGBR-30 is the lowest, indicating that the Maillard reaction may occur during the baking process. The a* value of the baked sample is higher than that of the unbaked sample, and the b* value of RGBR-20 is the highest. It decreases with the increase of baking time. It may be that RGBR-20 is in the middle stage of the Maillard reaction, and the b* value increases in this stage. As the baking time increases, the browning index of the sample gradually increases, which may be due to the reduction of protein content promoting the Maillard reaction. The browning index increases the most at 20 minutes of baking.

[0098] Table 5 Color of germinated brown rice before and after roasting

[0099]

[0100] Note: Data with different letters in the same column (mean ± standard deviation) are statistically significant (P<0.05)

[0101] (3) Analysis of volatile flavor substances: Fig.11 It can be seen that the volatile flavor substances of germinated brown rice have obvious differences after being roasted for different times (areas A, B, and C in the figure). The figure can intuitively show the change rules of volatile flavor substances of germinated brown rice before and after roasting. The volatile substances mainly include 28 aldehydes (hexanal, 3-methylbutanal, (Z)-4-heptenal, etc.), 20 alcohols (2-hexanol, 1-propanol, 5-methyl-2-furanmethanol, etc.), 18 ketones (1-penten-3-one, 2,3-butanedione, 2-heptanone, etc.), 14 esters (ethyl acetate, hexyl acetate, isoamyl butyrate, etc.), 17 heterocyclics (tetrahydrofuran, 2-acetyl-1-pyrroline, 2-pentylfuran, etc.) and 4 acids, including monomers and dimers of some substances. With the extension of baking time, the relative contents of ketones and alcohols in germinated brown rice flour decreased, while the relative contents of esters and heterocyclic substances gradually increased. This may be due to the esterification of alcohols with fatty acids to form esters, and the Strecker degradation of ketones to produce heterocyclic substances, which led to changes in the content of volatile substances, while the changes in the content of aldehydes and acids were not obvious. It can be seen that after baking, the main volatile components of germinated brown rice, esters and heterocyclic substances, increased, producing a pleasant aroma, which is more acceptable and liked.

[0102] (4) Analysis of gelatinization degree, water solubility index and water absorption index: As shown in Table 6, with the extension of baking time, the gelatinization degree of germinated brown rice gradually increases. When the baking time is 20min, the gelatinization degree can reach 75.31%, which basically reaches the degree of maturation. If the baking time continues to extend, the gelatinization phenomenon becomes more obvious, which may affect the mouthfeel of germinated brown rice. After baking, the water solubility index and water absorption index increase. It may be that part of the starch of germinated brown rice produces gelatinization during baking, the structure becomes loose and porous, the hydrogen bonds between starch molecules are destroyed, and they are connected with water molecules, so that the water solubility and water absorption of germinated brown rice increase, thereby improving the instant solubility of brown rice powder.

[0103] Table 6 Gelatinization degree, water solubility index and water absorption index of germinated brown rice before and after roasting

[0104]

[0105] Note: Data with different letters in the same column (mean ± standard deviation) are statistically significant (P<0.05)

[0106] (5) Gelatinization characteristics analysis: From Table 7 and Fig.12 It can be seen that the peak viscosity gradually decreases with the extension of baking time. It may be that as the baking progresses, the starch granules of germinated brown rice are partially gelatinized or damaged after baking, and lose the ability to retain internal osmotic water and cannot expand to the maximum size, resulting in a decrease in viscosity. The peak viscosity of RGBR-20 is the lowest. The subsequent increase in peak viscosity may be due to the formation of starch-lipid complexes, which delays the degradation of starch and reduces the resistance to digestive enzymes. The disintegration value can predict the trend of expansion, disintegration and binding force changes of starch granules. The swelling behavior of starch granules of germinated brown rice changes after baking. The final viscosity gradually decreases with the extension of baking time. It may be that increasing the degree of baking will lead to a decrease in the polymerization of amylose and amylopectin, which may reduce the final viscosity. The retrogradation value can reflect the speed of starch retrogradation after gelatinization. As the baking progresses, the retrogradation value decreases, indicating that germinated brown rice is less likely to age and retrogradation after baking. It can be seen that baking can make germinated brown rice more fully gelatinized and easier to digest and absorb.

[0107] Table 7 Gelatinization properties of germinated brown rice before and after roasting

[0108]

[0109] Note: Data with different letters in the same column (mean ± standard deviation) are statistically significant (P<0.05)

[0110] (6) Rheological properties analysis: Experimental results are as follows Fig.13 As shown by Fig.13It can be seen that the elastic modulus (G'), viscous modulus (G") and loss coefficient tanδ (G" / G') show an increasing trend with increasing frequency, and G' is higher than G", indicating that the heat treatment during baking affects the structure of the germinated brown rice gel. It may be that during the baking process, the dissolution of amylose and small molecular branched starch forms a gel network with a relatively stable structure. The G' value of RGBR is higher than that of GBR, and increases with the extension of baking time, indicating that baking can significantly improve the elasticity of germinated brown rice starch paste. The G" value of RGBR is also higher than that of GBR, but its increment is smaller than G'. The tanδ values ​​of GBR and RGBR are both less than 1, and the tanδ decreases after baking treatment, reflecting the increase in the elastic ratio of the system. It can be seen that after baking treatment, the elasticity and fluidity of the germinated brown rice starch paste are enhanced, among which RGBR-20 has the highest G' value and the smallest tanδ value.

[0111] In summary, after baking, the basic nutrients and bioactive components of germinated brown rice decreased, but compared with ungerminated brown rice, the contents of γ-aminobutyric acid, total phenols, total flavonoids, γ-oryzanol and glutathione increased by 260.61%, 41.18%, 61.68%, 35.82% and 33.67%, respectively; with the extension of baking time, the color gradually darkened, esters and heterocyclic substances increased, and a pleasant aroma was produced; after baking, the gelatinization degree, water solubility index and water absorption index of germinated brown rice increased, the peak viscosity, valley viscosity, final viscosity and regeneration value decreased significantly, the anti-aging ability increased, and the elasticity and fluidity were enhanced. Considering comprehensively, the baking condition was selected as 120℃ baking for 20min.

[0112] Example 3

[0113] Sprouted and roasted brown rice was used as raw material and processed by ultrafine grinding technology. The effect of ultrafine grinding on the palatability and reconstitution properties of sprouted and roasted brown rice was explored by studying the physicochemical properties of powder, such as particle size, basic nutrients and bioactive ingredients, dispersibility in dissolution, flowability, hydration properties and gelatinization properties.

[0114] The preparation of germination-baking-ultrafine grinding brown rice powder comprises the following steps: selecting the germinated brown rice baked for 20 min at 120 ℃ among the embodiment 2, coarse grinding and ultrafine grinding are carried out to the germination-baking brown rice, and the brown rice powder of different order is obtained, and sifting out 60-120 order is recorded as brown rice coarse meal, 120-180 order is recorded as brown rice fine powder I, 180-240 order is recorded as brown rice fine powder II, 240-300 order is recorded as brown rice fine powder III and greater than 300 order is recorded as brown rice fine powder IV respectively.

[0115] 3.1 Experimental methods

[0116] (1) The determination of particle size includes the following steps: taking an appropriate amount of sample into a 10 mL centrifuge tube, adding 10.0 mL of deionized water and placing it in an ultrasonic cleaner for full oscillation for 5 min to make it evenly dispersed, injecting it into a sample pool through a 0.45 μm filter membrane, and measuring the particle size of the powder by a laser particle size analyzer.

[0117] (2) Determination of basic nutrients and bioactive components: The determination method is the same as the index analysis determination method in 1.2 of Example 1.

[0118] (3) Determination of dispersibility of preparation

[0119] The determination of water solubility index and water absorption index includes the following steps: accurately weigh 3.0g of sample and place it in a centrifuge tube with constant weight, add 30.0mL of distilled water, heat in a water bath at 60℃ for 30min, then centrifuge at 4000r / min for 20min, transfer the supernatant into an aluminum box with constant weight, evaporate and dry to constant weight at 105℃. The calculation formulas of water solubility index and water absorption index are as follows.

[0120] Water solubility index (%) = (m4-m3) / M×100% Formula (5)

[0121] Water absorption index (g / g) = (m2-m1) / M Formula (6)

[0122] In the formula: m1 is the mass of the centrifuge tube at constant weight, g; m2 is the mass of the centrifuge tube containing the precipitate, g; m3 is the mass of the aluminum box at constant weight, g; m4 is the mass of the aluminum box after the supernatant has evaporated, g; M is the mass of the sample, g.

[0123] The determination of dispersion time includes the following steps: accurately weigh 5.0 g of sample, slowly add it into a beaker containing 50.0 mL of 80° C. water through a glass funnel, stir magnetically at a rate of 30 r / min, and determine the time (s) for the sample to be completely dispersed in water.

[0124] The wettability determination includes the following steps: adding 50.0 mL of water to a glass dish with a diameter of 10 cm, accurately weighing 0.1 g of sample and placing it on the water surface, and determining the time (s) for the powder to be completely wetted by water, i.e., the wettability.

[0125] The determination of the caking rate includes the following steps: accurately weigh 10.0 g of the sample, pour it into 100.0 mL of 80°C water, stir it thoroughly for 30 seconds, let it stand for 5 minutes, filter it with a constant weight 20-mesh sieve, and then dry the sieve at 105°C to constant weight. The caking rate calculation formula is as follows.

[0126] Agglomeration rate (%) = (M2-M1) / W×100 Formula (7)

[0127] Where: M1 is the mass of the sieve at constant weight, g; M2 is the mass of the sieve after drying, g; W is the mass of the sample, g.

[0128] (4) Determination of flow characteristics

[0129] The bulk density determination includes the following steps: take an appropriate amount of sample and add it to a 10mL measuring cylinder until it is full, scrape the powder at the mouth of the measuring cylinder flat, and determine the mass of the measuring cylinder filled with the sample. The bulk density calculation formula is as follows.

[0130] Tap density (g / mL) = (M2-M1) / 10 Formula (8)

[0131] Where: M2 is the mass of the measuring cylinder filled with sample, g; M1 is the mass of the measuring cylinder, g.

[0132] The tap density determination includes the following steps: accurately weigh 10.0g of sample into a 50mL measuring cylinder, repeatedly knock the measuring cylinder against the laboratory table from a height of 5cm every 2s until the volume of the sample in the measuring cylinder no longer changes, and determine the volume of the sample at this time. The tap density calculation formula is as follows.

[0133] Tap density (g / mL) = M / V formula (9)

[0134] Where: V is the volume of the sample after compaction, mL; M is the mass of the sample, g.

[0135] The determination of the angle of repose includes the following steps: fix the funnel vertically on an iron stand, place a glass plate with a diameter of 8.5 cm underneath, keep a certain distance between the bottom of the funnel and the glass plate, and let the sample flow vertically through the funnel to the glass plate to form a cone on the glass plate until the top of the cone reaches the bottom of the funnel. The diameter of the cone is measured, and the angle between the cone surface and the plate is the angle of repose. The formula for calculating the angle of repose is as follows.

[0136] Angle of repose (°) = arctan (2h / D) Formula (10)

[0137] Where: h is the distance from the bottom of the funnel to the glass dish, cm; D is the diameter of the cone, cm.

[0138] The measurement of the sliding angle includes the following steps: accurately weigh 1.0g of sample and place it on a glass plate, slowly lift one end of the plate in a 90° direction until the sample starts to slide from the plate, measure the vertical height of the lifted end of the plate from the table, and the angle between the plate and the table is the sliding angle. The sliding angle calculation formula is as follows.

[0139] Slip angle (°) = arcsin (H / L) Formula (11)

[0140] Where: H is the vertical height between one end of the raised plate and the tabletop, cm; L is the length of the glass plate, cm.

[0141] (5) Determination of hydration characteristics

[0142] The determination of water holding capacity includes the following steps: accurately weigh 1.0g of sample and place it in a centrifuge tube with constant weight, add 20.0mL of distilled water, stir magnetically for 30min at 60℃, centrifuge at 3000r / min for 20min, remove the upper layer of water, and then determine the mass of the centrifuge tube. The water holding capacity calculation formula is as follows.

[0143] Water holding capacity (g / g) = (m2-m1-m0) / m0 Formula (12)

[0144] In the formula: m1 is the mass of the centrifuge tube with constant weight, g; m2 is the mass of the centrifuge tube containing the precipitate, g; m0 is the mass of the sample, g.

[0145] The determination of oil holding capacity includes the following steps: accurately weigh 1.0g of sample and place it in a centrifuge tube with constant weight, add 20.0mL of soybean oil, stir magnetically for 30min at 60℃, centrifuge at 3000r / min for 20min, remove the upper oil, and then determine the mass of the centrifuge tube. The oil holding capacity calculation formula is as follows.

[0146] Oil holding capacity (g / g) = (m2-m1-m0) / m0 Formula (13)

[0147] In the formula: m1 is the mass of the centrifuge tube with constant weight, g; m2 is the mass of the centrifuge tube containing the precipitate, g; m0 is the mass of the sample, g.

[0148] The determination of swelling degree includes the following steps: accurately weigh 1.0 g of sample into a measuring cylinder, then add 50.0 mL of distilled water into the measuring cylinder, determine the volume of the sample, stir evenly and let it stand at room temperature for 24 hours, and record the volume of the sample after natural swelling. The swelling degree calculation formula is as follows.

[0149] Swelling degree = (V2-V1) / m Formula (14)

[0150] Where: V1 is the volume before swelling, mL; V2 is the volume after swelling, mL; m is the sample mass, g.

[0151] (6) Determination of gelatinization characteristics: The determination method is the same as (5) Determination of gelatinization characteristics in 2.1 Experimental method in Example 2.

[0152] 3.2 Data processing and analysis

[0153] The experimental results are expressed as "mean ± standard deviation", and all experiments were repeated three times under the same conditions. Excel 2016 software was used for data analysis, Origin 2024 was used for drawing, and SPSS 26.0 was used for variance analysis.

[0154] 3.3 Experimental results and analysis

[0155] (1) Particle size analysis: Fig.14 It can be seen that brown rice meal presents two distribution peaks within the scope of 10-100nm and 100-1000nm respectively, causes the change of distribution peak after ultrafine grinding treatment, the distribution peak of 10-100nm weakens or even disappears, and the distribution peak value is all shifted to the left, indicating that the overall particle size of germination-baking brown rice powder after ultrafine grinding treatment is reduced, and particle diameter becomes more uniform. As shown in Table 8, the pulverizing order number is negatively correlated with the average particle size, and along with the reduction of powder particle size, discreteness is the trend of first reducing and then increasing, and discreteness can represent the distribution range of particle size, and brown rice micro powder II discreteness is the minimum, indicating that its powder particle size is concentrated and evenly distributed, and discreteness increases subsequently, which may be further smaller of particle size, and specific surface area increases, and agglomeration phenomenon is easily produced.

[0156] Table 8 Particle size related parameters of germinated-baked brown rice flour before and after ultrafine grinding

[0157]

[0158] Note: Data with different letters in the same column (mean ± standard deviation) are statistically significant (P<0.05)

[0159] (2) Comparative analysis of basic nutrients and bioactive components: Fig.15 It can be seen that as the particle size of the powder decreases, the content of protein, starch, fat, dietary fiber and reducing sugar in the germinated-baked brown rice powder increases to varying degrees. It may be that during the ultrafine grinding process, the powder is subjected to strong friction and shear force, the cell wall is broken, and the dissolution of substances such as protein, fat, starch, etc. is increased, which increases the content of the powder's nutritional components. Ultrafine grinding destroys the cell wall structure of the germinated-baked brown rice powder. As the particle size of the powder decreases, more bioactive ingredients are attached to the surface, resulting in increased exposure of the main active ingredients such as γ-aminobutyric acid, total phenols, total flavonoids and γ-oryzanol, thereby increasing the content of the active ingredients in the powder.

[0160] (3) Dispersion analysis: As shown in Table 9, as the particle size of the powder decreases, the water solubility index increases significantly. This may be due to the ultrafine grinding process that causes some insoluble substances in the germinated-baked brown rice powder to melt or break bonds, which is converted into soluble substances, thereby improving the water solubility index. The water absorption index increases gradually with the decrease in the particle size of the powder. This may be because the specific surface area of ​​the germinated-baked brown rice powder increases after the ultrafine grinding process, and the sites of linear / branched starch, polar groups, etc. that are combined with water increase, thereby having a higher water absorption index. As the particle size of the powder decreases, the dispersion time, wettability, and caking rate increase gradually. The reason for this is that the specific surface area of ​​the powder increases, so that adsorption and agglomeration between each other are improved, which affects the dispersion effect of the germinated-baked brown rice powder. Taking all factors into consideration, the dispersion of brown rice micropowder II is the best.

[0161] Table 9 Dispersibility of germinated-baked brown rice flour before and after ultrafine grinding

[0162]

[0163] Note: Data with different letters in the same column (mean ± standard deviation) are statistically significant (P<0.05)

[0164] (4) Analysis of flow characteristics: As shown in Table 10, as the particle size of the powder decreases, the bulk density and tap density of the germinated-baked brown rice powder decrease significantly. This may be because the gaps between the powder particles increase, the contact area with the surrounding environment increases, and more air can be entrained, resulting in a decrease in the bulk density and tap density. The angle of repose gradually increases with the decrease in particle size. This may be because the specific surface area of ​​the particles increases as the particle size decreases, making it easy to absorb moisture in the air and form a cone with a larger angle; the sliding angle first increases and then decreases. The reason may be that the molecular attraction and electrostatic attraction between the particles gradually increase, and the particles are easy to aggregate and slide down, resulting in a further decrease in the sliding angle. Taking all factors into consideration, the powder flowability of brown rice micropowder II is the best.

[0165] Table 10 Flow properties of germinated-baked brown rice flour before and after ultrafine grinding

[0166]

[0167]

[0168] Note: Data with different letters in the same column (mean ± standard deviation) are statistically significant (P<0.05)

[0169] (5) Analysis of hydration characteristics: Fig.16It can be seen that with the decrease of powder particle size, the water holding capacity shows a trend of first increasing and then decreasing. The increase of specific surface area promotes the combination of hydroxyl groups on the particle surface with water molecules, which increases the water holding capacity. The reason for the decrease may be that the ultrafine grinding process destroys the polysaccharide chain of insoluble dietary fiber that can retain water through hydrogen bonds. The oil holding capacity shows a downward trend, which can be attributed to the fact that more hydrophilic groups are exposed in the germinated-baked brown rice powder during the ultrafine grinding process. The upward trend of swelling degree may be due to the increase of the specific surface area of ​​the powder particles, the increase of the interstitial rate, the increase of the opportunity for water molecules to enter the interstitial, and the increase of the volume occupied by the germinated-baked brown rice powder after absorbing water. Taking all factors into consideration, the hydration characteristics of brown rice micropowder II are the best.

[0170] (6) Gelatinization characteristics analysis: From Table 11 and Fig.17 It can be seen that compared with brown rice flour, after ultrafine grinding, as the particle size of the powder decreases, the peak viscosity, trough viscosity, disintegration value, final viscosity, regeneration value and gelatinization temperature of the germinated-baked brown rice flour gradually decrease. The decrease in peak viscosity may be due to the destruction of the crystal structure of the germinated-baked brown rice flour by ultrafine grinding; the disintegration value gradually decreases, indicating that the ultrafine grinding treatment improves the thermal stability of the germinated-baked brown rice flour, and the decrease in trough viscosity is due to the increase in the disintegration sensitivity of its starch granules due to the reduction in the particle size of the powder; the regeneration value significantly decreases, indicating that the ultrafine grinding treatment improves the anti-aging property of the germinated-baked brown rice flour; the gelatinization temperature gradually decreases, which may be due to the reduction in particle size, its ability to bind water is strong, and it takes a shorter time to form viscosity during the heating process, thereby reducing the gelatinization temperature. In summary, after ultrafine grinding, the germinated-baked brown rice flour can be mixed into a paste at a lower temperature, is not easy to age and regenerate, and exhibits good stability.

[0171] Table 11 Gelatinization properties of germinated-baked brown rice flour before and after ultrafine grinding

[0172]

[0173] Note: Data with different letters in the same column (mean ± standard deviation) are statistically significant (P<0.05)

[0174] In summary, after ultrafine grinding, the particle size of germinated-baked brown rice powder was significantly reduced, the content of basic nutrients increased, and the content of bioactive components such as γ-aminobutyric acid, total phenols, total flavonoids and γ-oryzanol increased; as the particle size of the powder decreased, the water solubility index, water absorption index, dispersion time, wettability, agglomeration rate, repose angle, and swelling degree gradually increased, the bulk density, tap density, and oil holding capacity gradually decreased, and the slip angle and water holding capacity first increased and then decreased, indicating that the dispersibility of the dispersible mixture was improved; after ultrafine grinding, the peak viscosity, valley viscosity, disintegration value, final viscosity, regeneration value, and gelatinization temperature all decreased, indicating that the anti-aging ability was enhanced and the stability was improved. Considering comprehensively, brown rice micropowder II was selected, with a mesh size of 180-240 mesh.

[0175] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing germinated brown rice powder rich in biologically active ingredients, characterized in that: The following steps are involved: (1) the brown rice is subjected to a germination treatment, wherein the germination treatment comprises removing impurities, washing, disinfecting, soaking, germination, drying and storage; the germination temperature is 25-35° C.; the germination time is 12-36 h; the soaking temperature is 30-40° C.; the soaking time is 4-12 h; and the concentration of the calcium chloride solution is 2-4 mmol / L; (2) baking after germination, the baking time is 10-30 minutes; (3) After baking, the powder is subjected to ultrafine grinding, and the grinding mesh size is 60-120 mesh, 120-180 mesh, 180-240 mesh or 240-300 mesh.

2. The method for preparing the germinated brown rice powder rich in biologically active ingredients according to claim 1, wherein: The germination temperature is 25-30°C, optimally, 29-30°C.

3. A method for preparing germinated brown rice powder rich in bioactive ingredients according to claim 1 or 2, characterized in that, The germination time is 24-36 hours, optimally, 24-25 hours.

4. The method for preparing a germinated brown rice powder rich in biologically active ingredients according to claim 1 or 2, characterized in that: The soaking temperature is 35-40°C.

5. The method for preparing a germinated brown rice powder rich in biologically active ingredients according to claim 1 or 2, characterized in that: The soaking time is 8-12 hours.

6. The method for preparing a germinated brown rice powder rich in biologically active ingredients according to claim 1 or 2, characterized in that: The concentration of the calcium chloride solution is 3-4 mmol / L, and optimally, 3.0-3.1 mmol / L.

7. The method for preparing a germinated brown rice powder rich in biologically active ingredients according to claim 1 or 2, characterized in that: The baking process is carried out in an electric oven at 120° C. for 20 minutes.

8. The method for preparing a germinated brown rice powder rich in biologically active ingredients according to claim 1 or 2, characterized in that: The ultrafine grinding adopts an ultrafine grinder, and the grinding mesh number is 180-240 meshes.

9. A germinated brown rice flour, characterized in that The preparation is prepared by the preparation method described in any one of claims 1 to 8.

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