Method and device for drying dried germinated brown rice with high gamma-aminobutyric acid content
The two-stage microwave vacuum drying process with controlled parameters and tray design effectively maintains high GABA content and improves cooking quality of sprouted brown rice by ensuring rapid, low-temperature drying and pre-gelatinization.
Patent Information
- Application Number
- CN202411516220.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2024-12-20
AI Technical Summary
Sprouted brown rice, rich in gamma-aminobutyric acid (GABA), requires drying to extend shelf life but high temperatures cause nutritional loss and poor cooking quality due to fiber hindering water absorption and starch gelatinization.
A two-stage microwave vacuum drying process with controlled microwave intensity, vacuum degree, and temperature, combined with a material tray design that alternately deforms to facilitate even drying, ensuring rapid water diffusion and pre-gelatinization without excessive heat.
Maintains high GABA content and improves cooking quality by reducing nutritional loss and internal stress, achieving rapid low-temperature drying with enhanced water diffusion and starch gelatinization.
Smart Images
Figure CN119157228A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of grain drying and processing. Background Art
[0002] Sprouted brown rice is obtained by germinating brown rice. It is rich in health-promoting ingredients such as dietary fiber, vitamins and gamma-aminobutyric acid (GABA). Among them, GABA has significant health and medical value in lowering blood pressure, alleviating diabetes, improving sleep quality and delaying neuronal aging. The moisture content of fresh wet sprouted brown rice is higher than 30%, so it needs to be dried to extend its shelf life. However, the higher temperature of the dry environment will cause the loss of nutritional qualities such as GABA. At the same time, the fiber layer on the surface of the sprouted brown rice will hinder its water absorption and starch gelatinization during the cooking process, resulting in poor cooking quality. Summary of the invention
[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a method and device for drying germinated brown rice with a high γ-aminobutyric acid content. The dried germinated brown rice obtained by the method provided by the present invention has a GABA content of up to 35.45 mg / 100 g and the cooking quality is effectively improved.
[0004] Technical solution: To achieve the above-mentioned purpose, the drying method of the germinated brown rice with high γ-aminobutyric acid content of the present invention comprises the following steps:
[0005] Step 1, draining the fresh wet germinated brown rice after the germination process;
[0006] Step 2: Spread the drained fresh wet germinated brown rice on each material plate and put it into a microwave vacuum drying device;
[0007] Step 3, drying the germinated brown rice under the conditions of microwave intensity of 9W / g to 11W / g, vacuum degree of 0.04MPa to 0.06MPa, drying temperature of 50°C to 70°C, and drying time of 8min to 10min, and turning off the microwave source after drying;
[0008] Step 4: Based on step 3, take out the germinated brown rice and refrigerate it at room temperature for 7 to 9 minutes;
[0009] Step 5. On the basis of step 4, the microwave intensity is adjusted to 14W / g-16W / g, the vacuum degree is 0.06MPa-0.08MPa, and the drying time is 2min-3min; the germinated brown rice is subjected to a second microwave vacuum drying; after the drying is completed, the germinated brown rice is taken out and allowed to stand for 20min-30min.
[0010] Furthermore, the draining time in "step 1" is 30 minutes to 40 minutes, and the moisture content of the germinated brown rice after draining is 33% to 35%.
[0011] Furthermore, the microwave frequency of the microwave vacuum drying equipment in "Step 2" is 2450 MHz.
[0012] Furthermore, during the microwave vacuum drying process of "step three" and "step five", the material bearing surface of the material tray is periodically and alternately deformed into an upward convex conical surface and a downward concave conical surface;
[0013] When the material bearing surface of the material tray changes from a concave cone to a convex cone, the fresh and wet germinated brown rice material originally gathered in the center of the material bearing surface spreads to the surroundings and rolls to the material bearing surface under the action of gravity;
[0014] When the material bearing surface of the material tray changes from an upward convex cone surface to a downward concave cone surface, the fresh wet germinated brown rice material originally scattered on the edge of the material bearing surface rolls toward the center under the action of gravity and gathers in the center of the material bearing surface.
[0015] Furthermore, the vacuum microwave drying material plate for dried germinated brown rice with high γ-aminobutyric acid content comprises a plurality of material plates coaxially and equidistantly distributed vertically, wherein the material plate comprises a coaxial surrounding wall, a flexible conical material-carrying air-permeable thin wall and a central plate; the outer ring contour of the flexible conical material-carrying air-permeable thin wall is fixedly connected to the inner wall of the surrounding wall, and the inner ring contour of the flexible conical material-carrying air-permeable thin wall is fixedly connected to the outer contour of the central plate; the upper surface of the flexible conical material-carrying air-permeable thin wall is the material-carrying surface;
[0016] It also includes a traction line extending along the axis of each material tray. The center of the central disk of each material tray is fixedly connected to the traction line, and each central disk can be synchronously moved up and down under the up and down pulling of the traction line.
[0017] Furthermore, the surface of the flexible conical material bearing the breathable thin wall is provided with a plurality of material-blocking ring protrusions with gradually increasing radius from the center to the edge, the protrusion thickness of the material-blocking ring protrusion is 5 mm, and the material is silicone.
[0018] Furthermore, when the traction line is pulled up and down periodically, each central disk is synchronously displaced up and down periodically under the pulling of the traction line, so that the material bearing surface of the material disk is periodically and alternately deformed into an upward convex conical surface and a downward concave conical surface;
[0019] When the material bearing surface of the material tray changes from a concave cone to a convex cone, the fresh and wet germinated brown rice material originally gathered in the center of the material bearing surface spreads to the surroundings and rolls to the material bearing surface under the action of gravity;
[0020] When the material bearing surface of the material tray changes from an upward convex cone surface to a downward concave cone surface, the fresh wet germinated brown rice material originally scattered on the edge of the material bearing surface rolls toward the center under the action of gravity and gathers in the center of the material bearing surface.
[0021] Furthermore, the flexible conical material-bearing breathable thin wall is made of nylon fibers such as PA46 and PPA, and has good air permeability and heat resistance.
[0022] Beneficial effects: The microwave vacuum drying mode of the present invention enhances the water diffusion at a lower temperature and in a shorter time through the synergistic effect of microwave volume heating and the greater driving force provided by the high pressure difference in the vacuum environment, and can achieve rapid low-temperature drying of germinated brown rice. Effectively reduce the loss of nutritional quality. At the same time, the temperature control mode of microwave vacuum drying can induce pre-gelatinization of germinated brown rice. The cooking quality of germinated brown rice after drying is improved as follows:
[0023] 1. The present invention uses two different microwave vacuum drying methods to process fresh wet germinated brown rice. The first microwave vacuum drying uses constant temperature microwave vacuum drying, which is the gelatinization stage of the germinated brown rice. The drying temperature is set to 60°C, which can induce pre-gelatinization of the germinated brown rice and also prevent the excessive drying temperature from causing a reduction in the GABA content of the germinated brown rice.
[0024] 2. After the first stage of microwave vacuum drying, the germinated brown rice is slowly thawed, which is beneficial to reduce the internal moisture gradient of the germinated brown rice and reduce its internal stress difference, thereby reducing the crack rate. At the same time, the temperature of the germinated brown rice is reduced to prevent the subsequent drying process from being too high in temperature, which causes a reduction in GABA content.
[0025] 3. The second stage of microwave vacuum drying of the present invention is the dehydration stage of the germinated brown rice. Improving the microwave intensity and not controlling the drying temperature can quickly remove the excess water inside the germinated brown rice, so that the rice quickly reaches a safe moisture content (14% to 15%), thereby improving the drying efficiency.
[0026] In the process that the material bearing surface is periodically and alternately deformed into an upward convex cone surface and a downward concave cone surface, the material bearing surface will continuously and alternately gather and roll toward the center of the material bearing surface and spread and roll toward the edge of the material bearing surface, so that the fresh wet germinated brown rice material is dried more quickly and evenly under the joint promotion of continuous rolling and microwaves, thereby avoiding the problem that the water vapor of some fresh wet germinated brown rice materials cannot escape in a static stacking state; at the same time, the several material blocking ring protrusions of the present case play the effect of delaying and limiting the effect of hindering the fresh wet germinated brown rice material from gathering and spreading too quickly on the material bearing surface in the above process, so that the fresh wet germinated brown rice material can be more fully spread on the material bearing surface. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1It is a schematic diagram of the upper and lower coordination of several vacuum microwave material trays, including two states;
[0028] Figure 2 It is a schematic diagram of the structure of a single vacuum microwave material tray. DETAILED DESCRIPTION
[0029] The present invention will be further described below in conjunction with the accompanying drawings.
[0030] The drying method of the germinated brown rice with high γ-aminobutyric acid content of the present invention is further described below in conjunction with specific implementation examples, but the present invention is not limited to these examples.
[0031] Example 1
[0032] Step 1: drain the fresh wet germinated brown rice after the germination process for 30 minutes to 40 minutes to remove the water on the surface of the germinated brown rice; the moisture content of the germinated brown rice after draining is 33% to 35%; the measured moisture content of the germinated brown rice after draining is 33.8%.
[0033] Step 2: Spread the drained fresh wet germinated brown rice on each material plate 1, and the microwave frequency of the microwave vacuum drying equipment is 2450MHz;
[0034] Step 3: Dry the germinated brown rice at a constant temperature under the conditions of a microwave intensity of 10 W / g, a vacuum degree of 0.05 MPa, a drying temperature of 60° C., and a drying time of 9 min, and turn off the microwave source after drying.
[0035] Step 4: Based on step 3, take out the germinated brown rice and refrigerate it at room temperature for 8 minutes.
[0036] Step 5: Based on step 4, the microwave intensity is adjusted to 15 W / g, the vacuum degree is 0.07 MPa, the drying temperature is not controlled, and the drying time is 2.5 min. The germinated brown rice is subjected to a second microwave vacuum drying. After the drying is completed, the germinated brown rice is taken out and allowed to stand for 25 min. Thus, the dried germinated brown rice is obtained, and the moisture content of the dried germinated brown rice is measured to be 14% to 15%.
[0037] like Figure 1 and 2As shown, the arrangement of the material tray 1 in this case includes a number of material trays 1 coaxially and vertically equidistantly distributed, the material tray 1 includes a coaxial surrounding wall 6, a flexible conical material-carrying breathable thin wall 4 and a central tray 3; the outer ring contour of the flexible conical material-carrying breathable thin wall 4 is fixedly connected to the inner wall of the surrounding wall 6, and the inner ring contour of the flexible conical material-carrying breathable thin wall 4 is fixedly connected to the outer contour of the central tray 3; the upper surface of the flexible conical material-carrying breathable thin wall 4 is a material carrying surface 9; it also includes a traction line 2 extending along the axis of each material tray 1, the center of the central tray 3 of each material tray 1 is fixedly connected to the traction line 2, and each central tray 3 can be synchronously moved up and down under the up and down pulling of the traction line 2, the upper and lower ends of the traction line 2 are connected to a winch, and the surrounding walls 6 of each material tray 1 are fixed to the inner wall of the microwave vacuum drying equipment; the surface of the flexible conical material-carrying breathable thin wall 4 is provided with a number of material-carrying rings with gradually increasing radius from the center to the edge. The protrusion 5 and the protrusion of the material-blocking ring have a protrusion thickness of 5 mm and are made of silicone; when the traction line is periodically pulled up and down, each central disk 3 is periodically and synchronously displaced up and down under the up and down pulling of the traction line 2, so that the material bearing surface 9 of the material disk 1 is periodically and alternately deformed into an upper convex cone surface and a lower concave cone surface; when the material bearing surface 9 of the material disk 1 is transformed from a lower concave cone surface into an upper convex cone surface, the fresh and wet germinated brown rice material originally gathered in the center of the material bearing surface 9 is diffused and rolled to the material bearing surface 9 by gravity; when the material bearing surface 9 of the material disk 1 is transformed from an upper convex cone surface into a lower concave cone surface, the fresh and wet germinated brown rice material originally scattered at the edge of the material bearing surface 9 is rolled toward the center by gravity and gathered to the center of the material bearing surface 9; the flexible conical material-bearing breathable thin wall 4 is made of nylon fiber textile molding such as PA46 and PPA, and has good air permeability and heat resistance.
[0038] Based on the above structural characteristics, during the microwave vacuum drying process of the above "step three" and "step five", the material bearing surface 9 of the material tray 1 is periodically and alternately deformed into an upper convex conical surface and a lower concave conical surface; each cycle is 6s.
[0039] When the material bearing surface 9 of the material tray 1 is transformed from a concave cone to a convex cone, the fresh wet germinated brown rice material originally gathered in the center of the material bearing surface 9 spreads to the surroundings and rolls to the material bearing surface 9 under the action of gravity.
[0040] When the material bearing surface 9 of the material tray 1 is transformed from an upward convex cone surface to a downward concave cone surface, the fresh wet germinated brown rice material originally dispersed on the edge of the material bearing surface 9 rolls toward the center under the action of gravity and gathers in the center of the material bearing surface 9 .
[0041] In the process that the material bearing surface 9 is periodically and alternately deformed into the convex conical surface and the concave conical surface, the material bearing surface 9 will constantly and alternately gather and roll toward the center of the material bearing surface 9 and spread and roll toward the edge of the material bearing surface 9, so that the fresh wet germinated brown rice material is dried more quickly and evenly under the joint promotion of continuous rolling and microwaves, thereby avoiding the problem that the water vapor of some fresh wet germinated brown rice materials cannot escape under the static accumulation state; at the same time, the several material blocking ring protrusions 5 of the present case play the effect of delaying and limiting the effect of hindering the fresh wet germinated brown rice material from gathering and spreading too quickly on the material bearing surface 9 in the above process, so that the fresh wet germinated brown rice material can be more fully spread on the material bearing surface 9.
[0042] Example 2
[0043] A method similar to Example 1, except that the drying temperature of the first stage of microwave vacuum drying is reduced to 50°C.
[0044] Example 3
[0045] A method similar to Example 1, except that the drying temperature of the first stage of microwave vacuum drying is increased to 70°C.
[0046] Comparative Example
[0047] Spread the fresh wet sprouted brown rice on a tray and dry it naturally in the sun to a safe moisture content.
[0048] Test Case
[0049] The GABA content and cooking quality of the dried germinated brown rice prepared in Examples 1 to 3 and the comparative example were measured.
[0050] GABA content determination: Use colorimetry to determine, grind the germinated brown rice of each sample, weigh 1g, put it in a centrifuge tube, and add 5mL of deionized water. Filter after oscillation extraction for 1h. Take half a milliliter of filtrate, add 0.2mL (0.2mol / L, pH=9.0) boric acid buffer, 1mL6% phenol and 0.4mL9% sodium hypochlorite. After vigorous shaking, put the mixture in boiling water for 10 minutes, then put it in an ice bath for 20 minutes, and continue to shake until blue appears. Finally, add 2mL60% ethanol to the mixture. Using the blank solvent as a control, the absorbance value of the final extract was measured at 645nm using a spectrophotometer (I9, Jinan Haineng Instrument Co., Ltd.).
[0051] The cooking quality was characterized by the optimal cooking time, water absorption and post-cooking texture properties (hardness, elasticity and chewiness).
[0052] Determination of the optimal cooking time: Place 10g of dried germinated brown rice in a 250mL beaker, add 70mL of boiling water and boil for 10 minutes. Take out 10 rice grains every 1 minute and place them between two transparent glass plates to crush them. If no white core appears, it means that the dried germinated brown rice is cooked, and the corresponding cooking time is the optimal cooking time.
[0053] Water absorption rate: Put 5g of dried germinated brown rice into an aluminum container and add 50mL of distilled water for boiling water bath. The boiling water bath time is the optimal cooking time. After the boiling water bath, remove the water on the surface of the germinated brown rice after cooking and weigh it. The water absorption rate of the sample is calculated as follows:
[0054] Water absorption rate = (m f -m i ) / m i ,
[0055] In the formula, m i ——mass of the sample before cooking (g);
[0056] m f ——The mass of the sample after steaming (g).
[0057] Texture properties after cooking: The cooking process of the germinated brown rice was carried out in accordance with GB / T 15682-2008 “Sensory evaluation method for edible quality of rice and paddy for inspection of grains and oils”. The texture properties (hardness, elasticity and chewiness) of the germinated brown rice after cooking were determined using a texture analyzer (TA.XT Plus, Stable MicroSystem, UK) according to the standard TPA method.
[0058] The results are shown in Tables 1 and 2.
[0059] Table 1 Comparison results of GABA content
[0060]
[0061] Table 2 Cooking quality comparison results
[0062]
[0063] As shown in Table 1, the germinated brown rice can maintain a high GABA content when subjected to microwave vacuum drying at 50°C to 60°C. When the drying temperature reaches 70°C, the higher temperature will have an adverse effect on the GABA content. As shown in Table 2, when the first microwave vacuum drying temperature is 50°C (Example 2), the cooking quality is no different from that of the comparative example. This is because the drying temperature does not reach the gelatinization temperature of the germinated brown rice starch. When the drying temperature reaches above 60°C, the cooking quality of the germinated brown rice is improved (i.e., shortening the optimal cooking time of rice, reducing the hardness of rice, and improving the elasticity and chewiness of rice). This is because at the appropriate microwave vacuum drying temperature, the germinated brown rice starch is induced to undergo pre-gelatinization, which improves the internal starch structure of the germinated brown rice.
[0064] The results of the research show that the GABA content of the germinated brown rice prepared by the method is as high as 34.45 mg / 100 g, and the cooking quality of the germinated brown rice is effectively improved.
[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A method for drying germinated brown rice having a high γ-aminobutyric acid content, characterized in that: The steps include: Step 1, draining the fresh wet germinated brown rice after the germination process; Step 2: Spread the drained fresh wet germinated brown rice on each material plate (1), and place it in a microwave vacuum drying device; Step 3, drying the germinated brown rice under the conditions of microwave intensity of 9W / g to 11W / g, vacuum degree of 0.04MPa to 0.06MPa, drying temperature of 50°C to 70°C, and drying time of 8min to 10min, and turning off the microwave source after drying; Step 4: Based on step 3, take out the germinated brown rice and refrigerate it at room temperature for 7 to 9 minutes; Step 5. On the basis of step 4, the microwave intensity is adjusted to 14W / g-16W / g, the vacuum degree is 0.06MPa-0.08MPa, and the drying time is 2min-3min; the germinated brown rice is subjected to a second microwave vacuum drying; after the drying is completed, the germinated brown rice is taken out and allowed to stand for 20min-30min.
2. The method for drying the germinated brown rice with high γ-aminobutyric acid content according to claim 1, characterized in that: The draining time in "step 1" is 30 minutes to 40 minutes, and the moisture content of the germinated brown rice after draining is 33% to 35%.
3. The drying method of the dried germinated brown rice with high γ-aminobutyric acid content according to claim 1, characterized in that: The microwave frequency of the microwave vacuum drying equipment in "Step 2" is 2450MHz.
4. The drying method of the dried germinated brown rice with high γ-aminobutyric acid content according to claim 1, characterized in that: During the microwave vacuum drying process of "step three" and "step five", the material bearing surface (9) of the material plate (1) is periodically and alternately deformed into an upward convex conical surface and a downward concave conical surface; When the material bearing surface (9) of the material plate (1) is transformed from a concave cone surface to a convex cone surface, the fresh and wet germinated brown rice material originally gathered in the center of the material bearing surface (9) spreads to the surroundings and rolls to the material bearing surface (9) under the action of gravity; When the material bearing surface (9) of the material tray (1) is transformed from an upward convex cone surface to a downward concave cone surface, the fresh wet germinated brown rice material originally scattered at the edge of the material bearing surface (9) rolls toward the center under the action of gravity and gathers at the center of the material bearing surface (9).
5. A vacuum microwave drying material tray for dried germinated brown rice with high γ-aminobutyric acid content, characterized in that: The material tray (1) comprises a plurality of coaxially equidistantly distributed material trays (1), wherein the material tray (1) comprises a coaxial surrounding wall (6), a flexible conical material-carrying air-permeable thin wall (4) and a central tray (3); the outer ring contour of the flexible conical material-carrying air-permeable thin wall (4) is fixedly connected to the inner wall of the surrounding wall (6), and the inner ring contour of the flexible conical material-carrying air-permeable thin wall (4) is fixedly connected to the outer contour of the central tray (3); the upper surface of the flexible conical material-carrying air-permeable thin wall (4) is a material-carrying surface (9); It also includes a traction line (2) extending along the axis of each material tray (1), the center of the central disk (3) of each material tray (1) is fixedly connected to the traction line (2), and each central disk (3) can be synchronously moved up and down under the upward and downward pulling of the traction line (2).
6. The germinated brown rice vacuum microwave drying material tray with high γ-aminobutyric acid content according to claim 5, characterized in that: The surface of the flexible conical material-carrying air-permeable thin wall (4) is provided with a plurality of material-blocking ring protrusions (5) with gradually increasing radius from the center to the edge.
7. The germinated brown rice vacuum microwave drying material tray with high γ-aminobutyric acid content according to claim 6, characterized in that: When the traction line is pulled up and down periodically, each central disk (3) is periodically and synchronously displaced up and down under the up and down pulling of the traction line (2), so that the material bearing surface (9) of the material disk (1) is periodically and alternately deformed into an upward convex conical surface and a downward concave conical surface; When the material bearing surface (9) of the material plate (1) is transformed from a concave cone surface to a convex cone surface, the fresh and wet germinated brown rice material originally gathered in the center of the material bearing surface (9) spreads to the surroundings and rolls to the material bearing surface (9) under the action of gravity; When the material bearing surface (9) of the material tray (1) is transformed from an upward convex cone surface to a downward concave cone surface, the fresh wet germinated brown rice material originally scattered at the edge of the material bearing surface (9) rolls toward the center under the action of gravity and gathers at the center of the material bearing surface (9).
8. The vacuum microwave drying material tray for germinated brown rice with high γ-aminobutyric acid content according to claim 7, characterized in that: The flexible conical material-carrying air-permeable thin wall (4) is made by weaving nylon fibers.