A rice processing technology that minimizes nutrient loss

Abstract

This invention discloses a rice processing technology with minimal nutrient loss. First, ultrasonic cleaning removes impurities and mold, facilitating subsequent hulling and reducing the broken rice rate. Then, multi-stage micro-pressure milling further reduces nutrient loss and the broken rice rate. This processing method effectively reduces the broken rice rate and retains more nutrients compared to refined rice, with almost no impact on the taste.

Description

Technical Field

[0001] This invention relates to rice processing technology, specifically to a rice processing technology that minimizes nutrient loss. Background Technology

[0002] Most rice produced using current technology is highly processed, resulting in significant nutrient loss. While whole grains retain the endosperm, bran, and germ during processing and are rich in dietary fiber, the process involves grinding the grains into powder or granules, which differs from traditional rice and thus has low consumer acceptance. Brown rice, on the other hand, retains the common perception of rice and preserves the germ and bran layer. However, due to the presence of the germ and bran layer, brown rice is more prone to breakage during processing, more susceptible to spoilage during storage, and has a relatively harder texture. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a rice processing technology with less nutrient loss.

[0004] A rice processing technology with minimal nutrient loss involves multi-stage micro-pressure milling of hulled brown rice, separating the rice and bran layers. The bran layer (i.e., the outer layer) is then enzymatically hydrolyzed to obtain a liquid enzymatic hydrolysate. This liquid enzymatic hydrolysate is then sprayed onto the surface of the rice and dried until the moisture content is 13%-15%.

[0005] The aforementioned rice processing technology with minimal nutrient loss involves the following specific steps: Step 1: Impurity Removal: Select high-quality rice and remove stones, soil, and other impurities using conventional methods; Step 2: Washing and drying: Wash the rice treated in Step 1 with clean water 2-3 times under ultrasonic action, and then dry it with cold air until there is no obvious moisture on the surface of the rice. Step 3: Dehulling and screening: The rice processed in Step 2 is fed into the existing rice dehulling machine for dehulling, and then the existing screening equipment is used to effectively separate the rice husks from the brown rice and remove broken rice. Step 4: Multi-stage micro-pressure milling: The brown rice obtained in Step 3 is fed into a three-stage mill. The first-stage milling pressure is set to 0.01-0.03 MPa and the time is 1-5 min. The second-stage milling pressure is set to 0.05-0.08 MPa and the residence time is 30 s-1 min. The third-stage milling pressure is set to 0.1-0.2 MPa and the time is 10 s-30 s. Step 5: Negative pressure separation: The mixture obtained in step 4 is separated into rice and bran layers using conventional negative pressure separation equipment; Step 6: Enzymatic hydrolysis: The bran layer obtained in step 5 is mechanically crushed, and then added to an enzymatic hydrolysis solution for enzymatic hydrolysis. The enzymes used in the enzymatic hydrolysis solution are neutral protease, cellulase, and amylase, and the amounts of each enzyme are 1%-2%, 2%-3%, and 0.5%-1% of the total weight of the bran layer, respectively. The enzymatic hydrolysis time is 5-6 hours, and the temperature is 50-60℃. After the enzymatic hydrolysis is completed, inactivation and solid-liquid separation are performed, and the liquid is the enzymatic hydrolysis product. Step 7: Spraying and drying: Spray the enzymatic hydrolysis product obtained in step 6 evenly onto the surface of the rice, and then dry it with air at 10-20℃ until the moisture content of the rice is 13%-15%.

[0006] The clean water temperature used for cleaning in step 1 above is 10-15℃, and the time required for the first ultrasonic cleaning is 5-10 hours.

[0007] During the first wash, add salt to the clean water to make the salt water concentration 3%-5%.

[0008] Compared with the prior art, the present invention has the following beneficial effects: This invention first uses ultrasonic cleaning to remove impurities and mold, which also facilitates subsequent hulling and reduces the broken rice rate. Then, multi-stage micro-pressure milling is used to reduce nutrient loss and further reduce the broken rice rate. Through the processing of this invention, the broken rice rate can be effectively reduced, and compared with polished rice, more nutrients are retained with almost no impact on the taste of the rice. Detailed Implementation

[0009] Most rice on the market today is highly processed rice, which typically involves processes such as hulling, milling, polishing, and color sorting. During this processing, a significant amount of nutrients are lost, which contradicts current consumer expectations for healthy food. Therefore, our company has conducted research and development to enzymatically hydrolyze the bran layer after rice hulling, and then coat the rice surface with the hydrolysate to enrich its nutritional value. The specific process is as follows: Step 1: Impurity removal: Select high-quality rice and then remove stones, soil and other impurities through conventional sieves and air separation. Step 2: Washing and Drying: Wash the rice treated in Step 1 twice with clean water under ultrasonic treatment. The clean water temperature used for washing is 10-15℃. The ultrasonic washing time for the first time is 5-10 hours and the time for the second time is 2-3 hours. Add salt to the water used for the first washing to obtain a salt solution with a concentration of 3%-5%. Use tap water for the second washing. Then dry with cold air at 8-15℃ until there is no obvious moisture on the surface of the rice. Step 3: Dehulling and screening: The rice processed in Step 2 is fed into the existing rice dehulling machine for dehulling, and then the existing screening equipment is used to effectively separate the rice husks from the brown rice and remove broken rice. Step 4: Multi-stage micro-pressure milling: The brown rice obtained in Step 3 is fed into a three-stage mill. The first-stage milling pressure is set to 0.01-0.03 MPa and the time is 1-5 min. The second-stage milling pressure is set to 0.05-0.08 MPa and the residence time is 30 s-1 min. The third-stage milling pressure is set to 0.1-0.2 MPa and the time is 10 s-30 s. Step 5: Negative pressure separation: The mixture obtained in step 4 is separated into rice and bran layers using conventional negative pressure separation equipment; Step 6: Enzymatic hydrolysis: The bran layer obtained in step 5 is mechanically crushed, and then added to an enzymatic hydrolysis solution for enzymatic hydrolysis. The enzymes used in the enzymatic hydrolysis solution are neutral protease, cellulase, and amylase, and the amounts of each enzyme are 1%-2%, 2%-3%, and 0.5%-1% of the total weight of the bran layer, respectively. The enzymatic hydrolysis time is 5-6 hours, and the temperature is 50-60℃. After the enzymatic hydrolysis is completed, inactivation and solid-liquid separation are performed, and the liquid is the enzymatic hydrolysis product. Step 7: Spraying and drying: Spray the enzymatic hydrolysis product obtained in step 6 evenly onto the surface of the rice, and then dry it with air at 10-20℃ until the moisture content of the rice is 13%-15%. Example

[0010] Step 1: Select high-quality rice that meets national or industry standards, and remove gravel, soil and other impurities by using an electric winnowing machine and a screening machine. Step 2: First, prepare a 3% brine solution for the first rinse. Then, transport the rice grains to the brine via a conveyor belt and turn on multiple ultrasonic cleaners. The ultrasonic frequency is controlled at 28-30kHz, the intensity is 100W / L, and the rinsing time is 5-10 hours. After the first rinse, transfer the rice grains to a tap water tank for the second rinse. At this time, multiple ultrasonic cleaners are also set up, with the ultrasonic frequency controlled at 35-40kHz and the intensity at 200W / L. The rinsing time is 2-3 hours. Finally, dry the rice grains with cold air at 8-15℃ until there is no obvious moisture on the surface. Step 3: Use a rice huller to dehull the washed rice, and then use existing screening equipment to effectively separate the rice hulls from the brown rice and remove broken rice to obtain brown rice; Step 4: Feed the brown rice into the three-stage mill. Set the first-stage milling pressure to 0.01-0.03 MPa and the time to 1-5 min, the second-stage milling pressure to 0.05-0.08 MPa and the residence time to 30 s-1 min, and the third-stage milling pressure to 0.1-0.2 MPa and the time to 10 s-30 s. Step 5: Use conventional negative pressure separation equipment to separate the rice from the bran layer. The rice can be graded in a conventional manner. Step 6: The obtained bran layer is mechanically crushed, and then added to an enzymatic hydrolysate for enzymatic hydrolysis. The enzymes used in the enzymatic hydrolysate are neutral protease, cellulase, and amylase, and the amounts of each enzyme are 1%-2%, 2%-3%, and 0.5%-1% of the total weight of the bran layer, respectively. The enzymatic hydrolysis time is 5-6 hours, and the temperature is 50-60℃. After the enzymatic hydrolysis is completed, the enzymes are inactivated and separated into solid and liquid components. The liquid component is the enzymatic hydrolysis product. Step 7: Spray the obtained enzymatic hydrolysis product evenly onto the surface of rice. Different grades of rice are sprayed separately. Then, dry the rice with air at 10-20℃ until the moisture content of the rice is 13%-15%.

Claims

1. A rice processing technique with less nutrient loss, characterized by, Specific is to shell after brown rice multi-stage micro-pressure grinding, and then separate out the rice and bran layer, wherein the bran layer (i.e. skin layer) is subjected to enzymatic hydrolysis to obtain a liquid enzymatic hydrolysate, and then the liquid enzymatic hydrolysate is sprayed onto the surface of the rice, and dried to a moisture content of 13%-15%.

2. The rice processing technique with less nutrient loss according to claim 1, wherein, The specific steps are as follows: Step 1: impurity removal: select high-quality rice, and then remove stones, soil and other impurities therefrom in a conventional manner; Step 2: washing and drying: wash the rice treated in step 1 with clean water under the action of ultrasonic waves for 2-3 times, and then dry with cold air until no obvious water is present on the surface of the rice; Step 3: shelling and screening: send the rice treated in step 2 into an existing rice huller for shelling, and then use existing screening equipment to effectively separate the rice husk and brown rice, and remove broken rice; Step 4: multi-stage micro-pressure grinding: send the brown rice obtained in step 3 into a three-stage grinding machine, set the first-stage grinding pressure to 0.01-0.03 Mpa, the time to 1-5 min, the second-stage grinding pressure to 0.05-0.08 Mpa, the residence time to 30 s-1 min, and the third-stage grinding pressure to 0.1-0.2 Mpa, the time to 10 s-30 s; Step 5: negative pressure separation: use conventional negative pressure separation equipment to separate the mixture obtained in step 4 into rice and bran layer; Step 6: enzymatic hydrolysis: mechanically crush the bran layer obtained in step 5, and then add an enzymatic hydrolysis solution to perform enzymatic hydrolysis, wherein the enzymes used in the enzymatic hydrolysis solution are neutral protease, cellulase and amylase, and the dosages of the enzymes are 1%-2%, 2%-3% and 0.5%-1% of the total weight of the bran layer, respectively, the enzymatic hydrolysis time is 5-6 h, and the temperature is 50-60℃; after the enzymatic hydrolysis is completed, inactivation and solid-liquid separation are performed, wherein the liquid is the enzymatic hydrolysate; Step 7: spraying and drying: uniformly spray the enzymatic hydrolysate obtained in step 6 onto the surface of the rice, and then dry with air at 10-20℃ until the moisture content of the rice is 13%-15%.

3. The low nutrient loss rice processing process according to claim 2, wherein, The clean water used for washing in the aforementioned step 1 has a temperature of 10-15℃, and the time for the first washing with ultrasonic waves is 5-10 h.

4. The low nutrient loss rice processing process according to claim 3, wherein, During the first washing, salt is added to the clean water used for washing, so that the concentration of the salt water used for washing is 3%-5%.