CN100432108C - Process for preparing rice starch and rice protein - Google Patents

Abstract

The invention discloses a method for preparing rice starch and rice protein, which belongs to the technical field of rice deep processing. The present invention uses broken rice, old rice, indica rice, japonica rice or glutinous rice as raw materials, after pulverization, superfine pulverization, enzymolysis reaction, centrifugation and separation, the precipitate is washed with water and then dried to be rice starch; Rice protein was prepared by spray drying. The obtained rice starch and rice protein are white in color, have no peculiar smell, and are rich in nutrition; the process design of the invention is scientific and reasonable, easy to operate, has no pollution to the environment, and can improve the comprehensive utilization value of rice processing and the economic benefits of grain production.

Description

A kind of preparation method of rice starch and rice protein

technical field

The invention discloses a method for preparing rice starch and rice protein, which belongs to the technical field of rice deep processing.

Background technique

Rice is one of the most important grains on earth. China's total rice output ranks first in the world, accounting for about 33% of the world's total output, which is about twice that of India and ten times that of Japan. Rice is a treasure all over the body. Rice, the main product of rice processing, as the main source of nutrition to meet the basic energy and nutritional needs of the human body, has made great contributions to solving the food problem of 1.6 billion people in my country in the 21st century. But for a long time, my country's rice processing has only been in a state of primary processing to meet people's ration needs. The structure of rice processing products is single, the level of comprehensive utilization of by-products is low, and deep processing accounts for only 20%, which is far lower than that of developed countries.

Rice starch and rice protein are developed from broken rice, aged rice, indica rice, japonica rice or glutinous rice through ultrafine pulverization and enzymatic hydrolysis reaction. As a starch product with unique properties, rice starch can be used in food, daily chemical and other industries for further development and utilization. Rice protein has rich nutritional value, high digestion and absorption, and hypoallergenicity. It can be used as a protein supplement in food, pet feed, etc., which can not only improve the comprehensive utilization value of rice processing and the economic benefits of grain production, but also Can make grain production embark on the road of virtuous circle.

Contents of the invention

The purpose of the present invention is to provide a kind of preparation method of rice starch and rice protein, the gained rice starch and rice protein product have unique taste and superiority in nutrition.

The technical scheme of the present invention: first crush raw materials such as broken rice, aged rice, indica rice, japonica rice or glutinous rice into coarse rice powder, then ultrafinely pulverize the coarse rice powder, add water, and add alkaline protease to carry out enzymatic hydrolysis reaction, After centrifugation, the precipitate is washed with water and dried to obtain rice starch; the supernatant is heated to inactivate enzymes, concentrated, and spray-dried to obtain rice protein.

(1) Crushing of raw materials such as broken rice, aged rice, indica rice, japonica rice or glutinous rice

The smaller the particle size of raw materials after crushing, the more thorough the separation of starch and protein, and the less residual protein in starch. Therefore, the raw materials should be coarsely pulverized first, requiring passing through a sieve of 80-100 mesh, and then superfinely pulverized so that the particle size of the rice flour can pass through a sieve of 180 mesh.

(2) Rice flour enzymatic hydrolysis reaction

solid to liquid ratio

The mass ratio of rice flour to water is controlled at 1:6-1:8. Although increasing the amount of water can improve the separation efficiency of rice starch and rice protein, it will also increase the amount of enzyme and the energy consumption of drying protein, so it is more suitable The solid-liquid ratio is 1:6-1:8, and the pH is adjusted to 7.5-8.5.

Enzyme reaction temperature and time

The present invention adds 2709 alkaline protease (20U/g), the amount of enzyme added is 0.20-0.25g/100g rice flour, and the optimum reaction temperature of enzyme is higher, which is 50-55°C, but it will not affect rice starch and rice protein properties, because the temperature of starch gelatinization and protein denaturation has not yet been reached. Prolonging the reaction time is beneficial to the thoroughness and completeness of the enzyme reaction, but too long reaction time will increase the production cost, so the enzyme reaction time of the present invention is 7-8 hours. The alkaline protease used is preferably 2709 alkaline protease (produced by Shanghai Huashida Industrial Co., Ltd.).

(3) Centrifugal separation

The three-legged centrifuge can effectively separate the rice starch precipitate and protein liquid after the enzyme reaction, and the centrifugation condition is 3000r/min, 20min.

(4) Wash and precipitate rice starch

Wash the precipitate obtained by centrifugation with water, control the water consumption to 3 to 4 times of the raw rice flour, wash 1 to 2 times, stir evenly and then centrifuge, wash and centrifuge the precipitate and carry out air-drying to make the moisture content below 12% , the product obtained is rice starch;

Washing can greatly reduce the residue of protein in the starch. Generally, 3-4 times of the raw material is needed to wash the starch for 1-2 times to reduce the residue of protein in the starch product to less than 0.5%, which meets the national standard.

(5) Treat the supernatant to obtain rice protein

After the enzymatic hydrolysis reaction, in order to prevent the further action of protease, the remaining enzyme activity was inactivated, and the temperature of the supernatant was raised to 90°C and kept for 5-10min.

Concentrate the supernatant with a falling film double-effect concentrator, and the concentrating condition is a temperature of 60-65° C., so that the solid content reaches 20%-25%. Then the concentrated feed liquid is spray-dried, and the air outlet temperature is 85° C., so that the moisture content is below 5%, and the dried product is rice protein.

Beneficial effects of the invention: the rice starch produced by the method of the invention has high purity and less than 0.4% protein residue, and is a starch product with multiple application paths. At the same time, the obtained rice protein has a purity of more than 65 percent and high nutritional value, and can be used as a nutritional supplement in food and pet feed. The present invention is a good example of rice development and utilization.

Description of drawings

Accompanying drawing is the schematic flow chart of the preparation process of rice starch and rice protein.

Detailed ways

Example 1

Take 15kg of rice flour that has been ultrafinely pulverized and passed through a 180-mesh sieve, add 90L of water, stir and mix well, heat to 50°C, add 30g (20U/g) of 2709 alkaline protease, and perform enzymatic hydrolysis for 8 hours. The reaction temperature is controlled at 50-55°C Centrifugal separation after the enzymolysis reaction, the precipitate was washed once with 60 L of water, and air-dried to obtain 7 kg of rice starch, so that the water content was below 12%. The supernatant was concentrated to 20%-25% solids. Then the concentrated feed liquid is spray-dried to obtain 1.2 kg of rice protein product, so that the moisture content is below 5%.

Example 2

Take 15kg of rice flour that has been ultrafinely pulverized and passed through a 180-mesh sieve, add 120L of water, stir and mix well, heat to 55°C, add 37g (20U/g) of 2709 alkaline protease, and perform enzymatic hydrolysis for 7 hours, with the reaction temperature controlled at 50-55°C Centrifugal separation after the enzymolysis reaction, the precipitate was washed twice with 45L water, and air-dried to obtain 7.5kg of rice starch, so that the water content was below 12%. The supernatant was concentrated to 20%-25% solids. Then the concentrated feed liquid is spray-dried to obtain 1 kg of rice protein product, so that the moisture content is below 5%.

Claims (2)

1, a kind of preparation method of rice starch and rice protein, it is characterized in that indica rice, japonica rice or glutinous rice are firstly pulverized into rice meal as raw material, then rice meal is carried out ultrafine pulverization, adds water, adds alkaline protease to carry out Enzyme hydrolysis, centrifugation, washing the precipitate with water and drying to produce rice starch; heating the supernatant to inactivate the enzyme, concentrating and spray-drying to obtain rice protein; (1) Raw material crushing: the raw material indica rice, japonica rice or glutinous rice is initially crushed into rice meal, which requires passing through a sieve of 80-100 mesh; (2) Superfine grinding: 180 mesh screen is required; (3) Enzymolysis reaction: add water to the rice flour after superfine pulverization, the mass ratio of rice flour and water is controlled to be 1:6～1:8, the pH is 7.5-8.5, add 2709 alkaline protease, and the enzyme amount is 0.20- 0.25g/100g rice flour, the temperature is controlled at 50-55°C, and the enzymatic hydrolysis time is kept for 7-8h; (4) centrifugal separation: the reaction feed liquid is centrifugally separated, and the centrifugal condition is 3000r/min, 20min; (5) Wash and precipitate rice starch: add water to wash the precipitate obtained by centrifugation, control the water consumption to 3 to 4 times of the raw rice flour, wash 1 to 2 times, stir well and then centrifuge, wash and centrifuge the precipitate for air flow Drying, so that the moisture content is below 12%, the product obtained is rice starch; (6) Treat the supernatant to obtain rice protein: supernatant at 90° C., 5-10 min to inactivate enzymes, and concentrate the supernatant at a temperature of 60-65° C. and concentrate to a solid concentration of 20%-25%; The concentrated feed liquid is spray-dried, and the air outlet temperature is 85° C., so that the moisture content is below 5%, and the dried product is rice protein. 2. The method for preparing rice starch and rice protein according to claim 1, characterized in that the enzyme activity of 2709 alkaline protease is 20 U/g.