Among cereal proteins, the biological value (B.V.) and protein value (P.V.) of rice protein are higher than other proteins. The amino acid composition of rice protein is balanced and reasonable, and the amino acid content is high, which is unmatched by other vegetable proteins. Rice protein is recognized as a high-quality food protein, which meets the ideal model recommended by WHO/FAO.
The biological value of rice protein is very high, and its nutritional value is high, comparable to that of eggs, milk, and beef. In addition, rice protein is a low-antigen protein, which will not cause allergic reactions, which is very beneficial for the production of infant food. Rice protein not only has unique nutritional functions, but also has other health functions.
Recent studies have shown that rice protein can lower serum cholesterol levels. Prevention of chronic diseases Reasonable nutrition diet can prevent some diseases, such as heart disease and cancer.
Analysis of Production Process of Rice Protein Separation and Purification
It is precisely because rice starch and rice protein have many advantages in industrial applications that the international market has a high demand for high-purity rice starch (the mass fraction of protein dry basis is less than 0.5%) and high-purity rice protein (protein dry basis content is higher than 90%). The need is growing. However, no matter it is rice starch or rice protein, in products using it as ingredients, functional properties such as water holding capacity, oil absorption and foaming properties are often more important than nutritional value such as amino acid composition, and the performance of functional properties is often affected by its purity.
Since the starch and protein in rice are closely combined and difficult to separate, the selection of separation and extraction methods for rice starch and rice protein directly affects the functional properties of the product.
The separation process of extracting rice protein from rice includes washing and soaking of rice, removing sand, refining, concentrating, and drying rice protein. And the enzyme treatment of protein slurry (including amylase, cellulase and lipase); the alkaline rice protein purification process includes lye soaking, grinding, stirring extraction, separation, acid precipitation, separation, drying, suitable for industrial production . But because there is no consideration of using the separated starch slurry to extract and separate starch, this process is not perfect for the development and utilization of raw materials, and does not make full use of raw materials.
Production process of filter washing and drying machine for separation and extraction of high-purity rice protein
Considering that the existing rice protein separation and purification production process has shortcomings such as long production cycle, high cost, and low product purity, it is especially difficult to simultaneously obtain high-purity and high-yield rice protein and rice starch in the same process. In view of the above problems, the filter washing and drying machine production process of separating and extracting high-purity rice protein is adopted, and high-purity rice starch and high-purity rice protein are simultaneously produced in the same treatment process, and purified after separating rice protein and rice starch, so the obtained product higher purity.
The production process of high-purity rice protein separation and extraction filter washing and drying machine soaks rice grains in lye, which has a high extraction rate and reduces the high energy consumption of the raw rice first crushed and then soaked; at the same time, due to the different drying methods, it is more conducive to ensuring the solubility of the product. Functional properties such as foaming and emulsifying properties.
A method for co-producing high-purity rice starch and rice protein, which comprises the following steps:
(1) Wash the rice with tap water, the weight ratio of rice to water is 1:2 to 1:6, and wash with water 1 to 3 times;
(2) Mix the washed rice with NaOH solution with a concentration of 0.1% to 0.5% at a solid-to-liquid ratio of 1:1.5 to 1:2.5, soak and stir at room temperature for 1h to 4h;
(3) Refining with colloid, so that the fineness of the rice pulp is 60 mesh to 150 mesh, settling and separating to obtain supernatant and precipitate 1;
(4) Use a filter, washing and drying machine, adjust the pH of the supernatant obtained from the colloid mill to 4.5-5.5 with hydrochloric acid, settle and separate to obtain a precipitate 2, add amylase or glucoamylase to the obtained precipitate 2, and heat it at 40°C-55°C , after hydrolysis for 10min to 30min, precipitate and separate to obtain precipitate 3;
(5) In the filter washing and drying machine, add water to the precipitate 3 according to the weight ratio of feed water to 1:2 to 1:8 and stir continuously, settle and separate to obtain the precipitate 4, repeat this step 3 to 5 times until the obtained Precipitation 4 with a neutral pH, and drying the precipitation 4 is high-purity rice protein powder;
(6) Purify the precipitate 1 obtained by colloid grinding with alkaline protease, separate to obtain the precipitate 5, adjust the pH of the precipitate 5 to neutral with hydrochloric acid, then purify with ethanol, settle and separate to obtain the precipitate 6;
(7) Add the precipitate 6 to tap water in an amount of 1:2 to 1:6 by weight ratio of feed to water, wash repeatedly 2 to 5 times, settle and separate to obtain the precipitate 7, and dry the obtained precipitate 7 to obtain high-purity rice starch .
The filtration, washing and drying machine production process for the separation and extraction of high-purity rice protein is a low-cost, high-quality method for the co-production of high-purity rice starch and rice protein. Its core is to use rice as raw material. Based on this, a new co-production of high-purity rice starch and rice protein technology has been developed to solve the existing technical problems to the greatest extent. Utilize this method can be on the basis of guaranteeing high product purity, make rice protein (protein purity ≥ 85%, yield ≥ 70%) and rice starch (starch purity ≥ 95%) and rice starch (starch purity ≥ 95%) with good functional properties and large molecular weight simultaneously, obtain rate ≥ 70%).