Method for improving the content of germinated red rice procyanidins by using complex stress treatment
Patent Information
- Application Number
- CN202411526740.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2026-09-25
- Estimated Expiration
- 2044-10-30
AI Technical Summary
本发明处理条件可有效控制红米籽粒的发芽状态，既能有效降低红米籽粒硬度，改善食用口感，又能保持较高的活性成分含量；可以解决目前红米食用品质较差的问题，并实现红米中特征性活性成分原花青素含量的富集和提升
[0028]本发明通过结合盐胁迫和低温胁迫的连续胁迫作用促进红米发芽，进而促进红米原花青素含量提高，可使红米中原花青素含量由1.46±0.06mg/g提高至3.08±0.05mg/g，并使红米的质构特性得到改善，其中硬度下降34.29～45.84％。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of grain processing technology, and in particular to a method for increasing the proanthocyanidin content of germinated red rice using compound stress. Background Technology
[0002] Red rice is a plant belonging to the genus Oryza in the family Poaceae. Its husk is yellow or brown. After removing the husk, the resulting grain is long-grained brown rice with a red seed coat. The main variety is indica glutinous rice, hence the name "red rice." Red rice contains 1.57 times more protein than ordinary rice, and its total essential amino acid content is 58.31% higher. Red rice contains various minerals essential for the human body. In addition, it contains a large number of bioactive substances, such as phenolic acids, flavonoids, γ-aminobutyric acid (GABA), and oryzanol. Especially noteworthy are the active pigments such as proanthocyanidins, which give red rice its bright red seed coat.
[0003] Proanthocyanidins, also known as concentrated tannins, are compounds polymerized from flavan-3-ol monomers. They are widely distributed in the plant kingdom, commonly found in fruits, vegetables, and colored grains. Numerous studies have shown that proanthocyanidins are natural antioxidants, participating in various metabolic activities and possessing beneficial physiological functions. They not only reduce cell damage caused by excessive free radicals and inhibit the spread and proliferation of cancer cells, but also have good anti-inflammatory effects, effectively reducing the risk of cardiovascular disease and helping to prevent and treat diabetes.
[0004] Since the content of proanthocyanidins in natural plant tissues cannot meet the human body's needs, this problem can be solved by promoting the germination of red rice to enrich proanthocyanidins. This is because the germination process of grains produces a variety of physiological changes that soften the grain structure, improve grain texture, and enhance the nutritional quality of the grain. Traditional methods for preparing germinated grains mostly involve water soaking, allowing the grains to absorb water and germinate in a high-moisture environment. However, these techniques generally suffer from problems such as long germination cycles, less than ideal improvements in edible quality, and less effective enrichment of active substances. Summary of the Invention
[0005] To address the aforementioned problems in existing technologies, this invention provides a method for increasing the proanthocyanidin content of germinated red rice using a compound stress treatment. The treatment conditions of this invention can effectively control the germination state of red rice grains, effectively reducing grain hardness and improving taste while maintaining a high content of active ingredients. This solves the current problem of poor red rice quality and achieves the enrichment and enhancement of the characteristic active ingredient proanthocyanidins in red rice.
[0006] The technical solution of the present invention is as follows:
[0007] The purpose of this invention is to provide a compound stress germination treatment method for increasing the proanthocyanidin content of red rice, which includes salt stress germination treatment and environmental temperature stress germination treatment, with a total stress germination treatment time of 12-36 hours.
[0008] The process of salt stress germination treatment was to spray with a NaCl solution of concentration of 30-120 mmol / L for 6-24 h;
[0009] The process of germination under environmental temperature stress involves treating the germination environment at a low temperature of 8-18℃ for 6-12 hours.
[0010] In one embodiment of the present invention, the combined stress germination treatment method specifically includes the following steps:
[0011] (1) Selection of raw materials: Select whole red rice grains that are plump, uniform in size, and without damage or insect infestation as raw materials;
[0012] (2) Cleaning and sterilization: Remove impurities mixed in with red rice grains, rinse with distilled water 1-2 times, and sterilize the red rice grains;
[0013] (3) Soaking treatment: Rinse the sterilized red rice grains with distilled water 5-8 times until the pH of the red rice grains is neutral, and then soak them in distilled water.
[0014] (4) Pre-germination: Drain the water and place the soaked red rice grains evenly in an open container for pre-germination.
[0015] (5) Stress treatment: After pre-germination, the red rice grains were evenly placed in an open container. Under constant temperature and humidity, the grains were first sprayed with a NaCl solution with a concentration of 30-120 mmol / L and then subjected to stress treatment for 6-24 hours. After washing, the grains were placed in a low temperature environment with a temperature of 8-18℃ for 6-12 hours.
[0016] In one embodiment of the present invention, in step (2), the sterilization treatment method is as follows: soak red rice grains in a 0.1% (g / L) sodium hypochlorite solution for 10-15 minutes.
[0017] In one embodiment of the present invention, the mass ratio of red rice grains to sodium hypochlorite solution is 10:8-13.
[0018] In one embodiment of the present invention, in step (3), the soaking conditions are: soaking at room temperature for 8-14 hours.
[0019] In one embodiment of the present invention, in step (4), the pre-germination time is 8-16 hours, the temperature is 20-30°C, and the humidity is 60-80%.
[0020] In one embodiment of the present invention, in step (4), pre-germination is carried out by spraying with distilled water.
[0021] In one embodiment of the present invention, in step (4), the open container is a petri dish lined with clean gauze. This allows the seeds to be evenly distributed and avoids the seedlings from being affected by overlapping seeds.
[0022] In one embodiment of the present invention, in step (5), the stress treatment is to cultivate red rice grains in an incubator with lighting and temperature control functions.
[0023] In one embodiment of the present invention, the temperature of the constant temperature and humidity environment is 20-30°C and the humidity is 75-85%.
[0024] In one embodiment of the present invention, in step (5), the mass of the sprayed NaCl solution is 0.9-1 times the mass of the red rice grains.
[0025] In one embodiment of the present invention, red rice can be replaced with black rice or purple rice.
[0026] Under stress treatment conditions, the sprout length of red rice can be controlled to not exceed the grain length, which can effectively reduce the hardness of red rice grains, improve the taste, and maintain a high content of active ingredients.
[0027] The beneficial technical effects of this invention are as follows:
[0028] This invention promotes the germination of red rice by combining continuous stress with salt stress and low temperature stress, thereby increasing the proanthocyanidin content of red rice. The proanthocyanidin content in red rice can be increased from 1.46±0.06mg / g to 3.08±0.05mg / g, and the textural properties of red rice are improved, with a decrease in hardness of 34.29-45.84%.
[0029] The red rice germination method of the present invention is simple, easy to implement, safe and reliable. The harvested germinated red rice grains can be cooked and eaten directly, and the eating quality is better than that of ungerminated red brown rice. It can also be used to make germinated red rice flour and other functional food ingredients, which have good effects on consumers' dietary therapy and health care. Attached Figure Description
[0030] Figure 1 These are actual photos of the red rice before and after the stress treatment in Example 1. Detailed Implementation
[0031] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0032] In this embodiment of the invention, whole red rice grains that are plump, uniform in size, and free from damage or insect infestation are selected as raw materials; impurities mixed in with the red rice grains are removed, and the grains are rinsed with distilled water 1-2 times before use.
[0033] Test methods
[0034] 1. Determination of proanthocyanidin content: Mix 2.0 g of sample powder with 20 mL of 80% acidified methanol. Extract the mixture at room temperature for 6 h in a shaker (300 r / min), then centrifuge and collect the supernatant. Mix 0.4 mL of the extract with 1 mL of 1% vanillin methanol solution (w / v) and 1 mL of 8% sulfuric acid / methanol solution (v / v), using anhydrous methanol as a control to eliminate interference from active anthocyanins or vanillin compounds. Incubate the mixture at 30 °C for 15 min, then measure the absorbance of the sample and control mixtures at 510 nm. The total proanthocyanidin content is expressed as mg catechin equivalents per g of sample dry weight (mg CE / g DW).
[0035] 2. Method for determining the texture quality of edible rice: Weigh 5g (accurate to 0.01g) of sample and place it in a clean 10mL aluminum crucible. Add purified water at a material-to-water ratio of 1:1.6 (w / v) and seal the crucible. Add an appropriate amount of purified water to an electric steamer, set the mode to the rice cooking setting, and place the aluminum crucible on the steamer rack after the water boils. After the cooking time is reached, remove the aluminum crucible and allow the cooked rice to cool at room temperature for 20 minutes before use. The texture quality of red rice was analyzed using a physical texture analyzer (TPA). The texture analyzer probe was P36R, and a double compression mode was used. Specific parameters were as follows: pre-test speed 1mm / s, test speed 0.5mm / s, post-test speed 1mm / s; trigger force 5.0g; and the compression ratio was 70%. The 3-grain rice method was used, with 10 parallel measurements for each sample, discarding the maximum and minimum measured values.
[0036] Example 1
[0037] A method for compound stress germination treatment to increase the proanthocyanidin content of red rice includes the following steps:
[0038] (1) Soak red rice grains in 0.1% (g / L) sodium hypochlorite solution for 10 min, wash with distilled water until the pH of the red rice grains is neutral, and then soak the grains in distilled water at 30℃ for 12 h to allow the grains to fully absorb water.
[0039] (2) After that, drain the water, spread the soaked red rice grains evenly on a petri dish lined with clean gauze, put it into an automatic germination machine with automatic water spraying function, place it in a dark environment at 25℃ and spray it with distilled water for 12 hours for pre-germination.
[0040] (3) Subsequently, the pre-germinated red rice grains were washed with distilled water and drained. After draining, the germinated red rice samples were spread evenly in a petri dish lined with four layers of gauze. The samples were first sprayed with a 60 mmol / L NaCl solution prepared with distilled water (the mass of the sprayed NaCl solution was equal to the wet weight of the red rice grains). The petri dishes were placed in a dark environment at 25°C for 24 h of salt stress. After washing and draining the samples, they were spread evenly in a petri dish lined with four layers of gauze and placed in a dark environment at 13°C for 12 h. The samples were then sprayed with distilled water for low temperature stress. After the low temperature stress treatment was completed, the germinated red rice samples were dried and the proanthocyanidin content was determined.
[0041] The results showed that the proanthocyanidin content of red rice reached 3.08±0.05 mg / g after germination treatment under the above conditions.
[0042] Example 2
[0043] A method for compound stress germination treatment to increase the proanthocyanidin content of red rice includes the following steps:
[0044] (1)-(2) Same as Example 1;
[0045] (3) Subsequently, the pre-germinated red rice grains were washed with distilled water and drained. After draining, the germinated red rice samples were spread evenly in a petri dish lined with four layers of gauze. The samples were first sprayed with a 60 mmol / L NaCl solution prepared with distilled water (the mass of the sprayed NaCl solution was equal to the wet weight of the red rice grains). The petri dishes were placed in a dark environment at 25°C for 24 h of salt stress. After washing and draining the samples, they were spread evenly in a petri dish lined with four layers of gauze and placed in a dark environment at 13°C for 8 h. The samples were then sprayed with distilled water for low temperature stress. After the low temperature stress treatment was completed, the germinated red rice samples were dried and the proanthocyanidin content was determined.
[0046] The results showed that the proanthocyanidin content of red rice reached 2.86±0.05 mg / g after germination treatment under the above conditions.
[0047] Example 3
[0048] A method for compound stress germination treatment to increase the proanthocyanidin content of red rice includes the following steps:
[0049] (1)-(2) Same as Example 1;
[0050] (3) Subsequently, the pre-germinated red rice grains were washed with distilled water and drained. After draining, the germinated red rice samples were spread evenly in a petri dish lined with four layers of gauze. The samples were first sprayed with a 60 mmol / L NaCl solution prepared with distilled water (the mass of the sprayed NaCl solution was equal to the wet weight of the red rice grains). The petri dishes were placed in a dark environment at 25°C for 24 h of salt stress. After washing and draining the samples, they were spread evenly in a petri dish lined with four layers of gauze and placed in a dark environment at 10°C for 12 h. The samples were then sprayed with distilled water for low temperature stress. After the low temperature stress treatment was completed, the germinated red rice samples were dried and the proanthocyanidin content was determined.
[0051] The results showed that the proanthocyanidin content of red rice reached 2.94±0.04 mg / g after germination treatment under the above conditions.
[0052] Example 4
[0053] A method for compound stress germination treatment to increase the proanthocyanidin content of red rice includes the following steps:
[0054] (1)-(2) Same as Example 1;
[0055] (3) Subsequently, the pre-germinated red rice grains were washed with distilled water and drained. After draining, the germinated red rice samples were spread evenly in a petri dish lined with four layers of gauze. The samples were first sprayed with a 60 mmol / L NaCl solution prepared with distilled water (the mass of the sprayed NaCl solution was equal to the wet weight of the red rice grains). The petri dishes were placed in a dark environment at 25°C for 24 h of salt stress. After washing and draining the samples, they were spread evenly in a petri dish lined with four layers of gauze and placed in a dark environment at 15°C for 12 h. The samples were then sprayed with distilled water for low temperature stress. After the low temperature stress treatment was completed, the germinated red rice samples were dried and the proanthocyanidin content was determined.
[0056] The results showed that the proanthocyanidin content of red rice reached 2.84±0.08 mg / g after germination treatment under the above conditions.
[0057] Comparative Example 1
[0058] Red rice was sterilized with 0.1% (g / L) sodium hypochlorite solution for 10 minutes, washed, and dried. The proanthocyanidin content in unsprouted red rice grains was then determined. The results showed that the proanthocyanidin content in unsprouted red rice grains was 1.46 ± 0.06 mg / g.
[0059] Comparative Example 2
[0060] (1)-(2) Same as Example 1;
[0061] (3) Subsequently, the pre-germinated red rice grains were washed with distilled water and drained. After draining, the germinated red rice sample was spread flat in a petri dish lined with four layers of gauze and sprayed with distilled water. The petri dish was placed in a dark environment at 25°C for germination for 12 hours. After the treatment, the germinated red rice sample was dried and the proanthocyanidin content was determined.
[0062] The results showed that after germination for a total of 24 hours under the above conditions, the proanthocyanidin content of red rice was 2.29 ± 0.21 mg / g. After a total germination time exceeding 48 hours, the sprouts grew longer than the grains and were prone to mold growth and fermentation odors.
[0063] Comparative Example 3
[0064] (1)-(2) Same as Example 1;
[0065] (3) Subsequently, the pre-germinated red rice grains were washed with distilled water and drained. After draining, the germinated red rice sample was spread flat in a petri dish lined with four layers of gauze and sprayed with distilled water. The petri dish was placed in a dark environment at 25°C for germination for 24 hours. After the treatment, the germinated red rice sample was dried and the proanthocyanidin content was determined.
[0066] The results showed that after germination for a total of 36 hours under the above conditions, the proanthocyanidin content of red rice was 2.40±0.11 mg / g. After a total germination time exceeding 48 hours, the sprouts grew longer than the grains and were prone to mold growth and fermentation odors.
[0067] Comparative Example 4
[0068] (1) Same as Example 1;
[0069] (2) After that, drain the water, spread the soaked red rice grains evenly on a petri dish lined with clean gauze, put it into an automatic germination machine with automatic water spraying function, place it in a dark environment at 30℃ and spray it with distilled water for 12 hours for pre-germination.
[0070] (3) Subsequently, the pre-germinated red rice grains were washed with distilled water and drained. After draining, the germinated red rice samples were spread evenly in a petri dish lined with four layers of gauze, sprayed with distilled water, and placed in a dark environment at 30°C for germination for 36 hours. The results showed that after a total germination time of 48 hours under the above conditions, the sprouts of the germinated red rice grains exceeded the length of the grains themselves, and the grains showed signs of cracking, softening, and mold growth, accompanied by a fermented odor.
[0071] Comparative Example 5
[0072] (1) Same as Example 1;
[0073] (2) After that, drain the water, spread the soaked red rice grains evenly on a petri dish lined with clean gauze, put it into an automatic germination machine with automatic water spraying function, place it in a dark environment at 30℃ and spray it with 60mmol / L NaCl solution for 48h to directly carry out salt stress treatment.
[0074] (3) Subsequently, the germinated red rice grains were washed with distilled water and drained. After drying the germinated red rice sample, the content of proanthocyanidins was determined.
[0075] The results showed that after 48 hours of salt stress treatment without pre-germination, the proanthocyanidin content in germinated red rice was 2.16±0.01 mg / g. No moldy or off-odors were observed in the red rice grains, but the metabolic rate of germinated red rice was faster at high temperatures, resulting in a lower proanthocyanidin content.
[0076] The edible texture quality of the compound-stressed red rice from Examples 1-4 and the untreated red rice was tested using a texture analyzer. The results of the edible texture quality test of the red rice are shown in Table 1 below:
[0077] Table 1
[0078]
[0079] As shown in Table 1, after germination stress treatment, the hardness, chewiness and stickiness of red rice decreased, while the changes in stickiness and elasticity were irregular and small. Furthermore, compared with single salt stress treatment, the combined stress treatment further improved the textural quality of red rice, especially the hardness index of red rice changed significantly.
[0080] The embodiments provided above are merely preferred embodiments of the present invention and should not be considered as limiting the scope and concept of the present invention, nor are they intended to limit the order of execution. Any obvious improvements made by those skilled in the art to the steps described in the present invention based on existing common knowledge, or equivalent substitutions and improvements made to different colored rice varieties such as red rice, purple rice, and black rice, also fall within the protection scope defined by the claims of the present invention.
Claims
1. A method for compound stress germination treatment to increase the proanthocyanidin content of red rice, characterized in that, The process includes salt stress germination treatment and ambient temperature stress germination treatment, with a total stress germination treatment duration of 12-36 h; under stress treatment conditions, the sprout length of red rice does not exceed the grain length; Specifically, the steps include the following: (1) Selection of raw materials: Select whole red rice grains that are plump, uniform in size, and without damage or insect infestation as raw materials; (2) Cleaning and sterilization: Remove impurities from the red rice grains and rinse with distilled water 1 The red rice grains were sterilized twice. (3) Soaking treatment: Rinse the sterilized red rice grains with distilled water for 5 minutes. Eight times until the red rice grains are at a neutral pH, then soak them in distilled water; (4) Pre-germination: Drain the water and place the soaked red rice grains evenly in an open container in a dark environment for pre-germination; the pre-germination time is 8-16 h, the temperature is 20-30 °C, and the humidity is 60-80%; (5) Stress treatment: After pre-germination, the red rice grains were evenly placed in an open container. Under constant temperature and humidity, they were first sprayed with a NaCl solution with a concentration of 30-120 mmol / L, and then subjected to stress treatment in a dark environment at 25°C for 6-24 h. After washing, they were placed in a dark low-temperature environment at 8-18 °C for 6-12 h. The mass of the sprayed NaCl solution is 0.9-1 times the mass of the red rice grains.
2. The method for treating germination under combined stress according to claim 1, characterized in that, In step (2), the sterilization method is as follows: soak red rice grains in 0.1% sodium hypochlorite solution for 10-15 minutes.
3. The method for treating germination under combined stress according to claim 2, characterized in that, The mass ratio of red rice grains to sodium hypochlorite solution is 10:8-13.
4. The method for treating germination under combined stress according to claim 1, characterized in that, In step (3), the soaking conditions are: soaking at room temperature for 8-14 hours.
5. The method for treating germination under combined stress according to claim 1, characterized in that, In step (4), the open container is a petri dish lined with clean gauze.
6. The method for treating germination under combined stress according to claim 1, characterized in that, In step (5), the stress treatment involves culturing red rice grains in an incubator with lighting and temperature control functions.
7. The method for treating germination under combined stress according to claim 1, characterized in that, The temperature and humidity of the constant temperature and humidity environment are 20-30 °C and 75-85%, respectively.