Views: 0 Author: Site Editor Publish Time: 2023-04-07 Origin: Site
Rice protein powder refers to the powdery substance formed from protein extracted from rice after processing such as milling, purification, and drying.
Rice protein powder is an important product of rice deep processing, which can be divided into feed grade rice protein powder, edible grade rice protein powder, and rice protein peptide based on its protein content and solubility.
Rice protein is mainly composed of four proteins: albumin, globulin, alcohol soluble protein, and gluten. The amino acid composition of rice protein is reasonable, and its amino acid content is high, which is recognized as a high-quality edible protein. Rice protein powder has broad prospects for development as infant and high-end food due to its high nutritional value and low allergenicity.
Rice protein has excellent nutritional quality and is recognized as a high-quality plant protein among cereal proteins. Rice protein can be roughly divided into four categories: Albumin, a protein soluble in water, accounting for 2% to 5% of the total amount; Globulins, soluble in 0.5mol/L NaCl solution, accounting for 2% to 10% of the total amount; Glutelin, soluble in dilute acids or alkalis, accounts for over 80% of the total amount; Prolamins, soluble in 70% to 80% ethanol solution, account for 1% to 5% of the total amount. Glutenin and gliadin become storage proteins, which are the main components of rice protein. And the content of albumin and globulin is relatively low, which are physiological active proteins in rice. Rice protein has good nutritional value due to its higher lysine content, higher essential amino acid content compared to other cereal proteins, higher biological value (BV), and protein utility ratio (PER).
1. Extract protein from rice
The purpose of extracting rice protein is to obtain high-purity rice protein products, which are generally divided into rice protein concentrate (RPC, protein content 50% -89%) and rice protein isolate (RPI, protein content above 90%). Raw materials such as crushed rice, rice grains, and rice bran can all be used to prepare rice protein. From the perspective of research progress both domestically and internationally, the main methods for extracting rice protein from rice include alkaline extraction, enzymatic extraction, solvent extraction, physical separation, and composite extraction.
2. Separation and washing
The crude substance of rice protein contains impurities such as starch, disaccharides, monosaccharides, and cellulose, which require further purification. The following steps take enzymatic extraction as an example.
The enzymolysis solution obtained in the previous process is centrifuged at a speed of 2000-4000 rpm for 5-15 minutes, and the obtained solid phase is washed with water equal to the enzymolysis solution for 3-5 times, and the washed solid phase is collected. The liquid phase contains nutrients such as glucose and can be used to produce feed yeast (single-cell protein).
The function of separation and washing is to remove non-protein impurities in the material.
3. Enzyme sterilization
Add an appropriate amount of water to the washing solid obtained from the previous process to achieve a solid content of 16-17% (weight percentage), and then boil the material for 30 minutes, or treat it at ultra-high temperature for 4-6 seconds at 115-121 ℃ for high-temperature treatment and enzyme sterilization.
4. Spray drying
The feed liquid obtained in the previous process is dried through a spray dryer to obtain high-purity rice protein powder. The inlet air temperature of spray drying is 165-180 ℃, the outlet air temperature is 75-85 ℃, and the spray pressure is greater than 0.7MPa. By using this process, the protein extraction rate is greater than 80%, and the dry weight percentage of the obtained high-purity soluble rice protein powder is greater than 80%, the fat weight percentage is less than 3%, and the ash weight percentage is less than 3%. High purity soluble rice protein powder has a wide range of uses and can be used in industries such as food, cosmetics, and pharmaceuticals.
China is a major rice producing country with abundant rice resources. Rice protein powder, as a conventional output material in the rice deep processing industry, has long been neglected. In recent years, thanks to in-depth research on rice protein, it has been favored by the food industry for its ability to compensate for the shortcomings of animal protein and prevent excessive intake of animal fat and cholesterol. The rice protein powder industry has broad market space. More importantly, further research and utilization of high-quality rice protein resources are conducive to the comprehensive utilization of rice deep processing, increasing the added value of rice, and developing the rice deep processing industry with technology as support, promoting the development of China's grain industry.
1. Food additives
Food additives are a type of additive that can improve the quality, color, aroma, and taste of food. The appropriate molecular size and amino acid composition will endow proteins with certain physicochemical properties, such as solubility, foaming, emulsifying, etc. Rice protein is more easily soluble in water and concentrated at the gas-liquid interface in a hydrophobic, flexible, and disordered structure, exhibiting foaming and emulsifying properties.
2. Protein nutritional supplements
Rice protein has become the preferred plant protein for nutritional supplementation for special populations due to its low allergenicity and high nutritional value. Rice noodles formulated with rice protein can be used to treat infantile diarrhea; Gluten free rice protein is more suitable for people with wheat intolerance, allergies, or abdominal diseases; Rice protein concentrate can better supplement the body capacity and maintain Nitrogen balance when the normal protein intake is reduced or the digestive function is damaged; And it can assist in the treatment of peptic ulcer, trauma, etc.
3. Development of functional peptides
Modern research has shown that amino acid residues in small molecule peptides are more easily digested and absorbed by the human body compared to free amino acids. Amino acids present in the form of small peptide molecules not only avoid transport competition, but also reduce the high concentration toxic side effects of amino acids. Peptide transport systems consume low energy and are not easily saturated, making the research on hydrolyzed protein products to obtain active peptides popular.
4. Protein feed
Rice protein powder, a by-product of the preparation of starch sugar from rice, is an excellent feed raw material with high protein content, fast energy conversion, high digestibility, good palatability, good disease resistance, low Antigenicity and amino acid balance. Adding rice gluten concentrate to aquatic feed can not only improve the digestive performance of fish, but also control their excretion, thereby maintaining clear water quality and controlling water pollution. Rice protease hydrolysis can produce flavor peptides that replace sodium glutamate (MSG). It can effectively mask bitterness, enhance feed viscosity, and improve feed palatability. It can also chelate trace elements and minerals, increasing animal feed intake while ensuring safety and harmlessness.