Study On Extraction, Modification Of Rice Protein And Its Physical And Chemical Properties

Rice residue is the production of monosodium glutamate, lactic acid, citric acid, and starch and sugar by-product, rich in 40% to 65% protein, has a good ratio of amino acids, and contains essential amino acids required for the body, and low allergy high nutritional value, is not fully developed plant protein resources, there is great economic value. In this study of rice starch to sugar by-products after rice residue as raw material, extracted rice proteins and the modification to improve functional properties of rice proteins, rice proteins arid further expand the application scope, aims to solve the problem the lack of quality protein,development and utilization of resources-rich rice proteins provide some experimental and theoretical basis. The main findings are as follows:1.Comparative study of four rice proteins extraction methodsIn this study, the alkaline protease,amylase-alkali cellulose enzyme and protein binding assay method of extraction of four rice proteins. The results showed that:①alkali extraction process is simple, low cost, but the rice proteins and the purity of the extraction rate of only 30.15%,75.9%;②Enzymatic hydrolysis of rice residue by reaction of the process curve analysis showed that alkaline protease enzyme m Java has a high enzyme activity, the purity of rice protein is 85%,but the extraction rate is not high, only about 45%;③Amylase-extraction of cellulose from rice protein extraction rate and the purity of rice protein both good,the value is 76.5% and 85%,but the physical and chemical properties is poor, solubility is only about 2.14%;④To increase the rate of protein extraction and purity, so that rice proteins with better physical and chemical properties, select the protease and alkali-step extraction of rice protein. The washing 2 rice residue material on temperature 90℃, according to 120u/g by adding high-temperature a-amylase, adjusted to optimum conditions for degradation of residual starch, enzyme, press 1200u/g by adding protease, the pH8.0,45℃condition, pre-hydrolysis 2hr, then dilute alkali conditioning reaction system pH12, at 45℃,liquid to solid ratio of 10:1 under the conditions of alkaline extraction 2hr, rice protein extraction rate reached 60.71%, purity 90.46%.2.Rice proteins modification of phosphorylation In this study, phosphorylation method was modified rice proteins. With sodium tripolyphosphate as the phosphorylation reagent, through analysis of single factor and orthogonal to the solubility of rice proteins as the main indicator to determine the optimal parameters modified by phosphorylation:STPP concentration of 6%, system pH8.5,reaction temperature 45℃,reaction time of 90min, the solubility of rice protein from up to 90.5%.3.Rice proteins modification of acylationIn this study, acylation method was modified rice proteins. Acylation with acetic anhydride as reagents, through analysis of single factor and orthogonal to the solubility of rice proteins as the main indicator to determine the optimal parameters of acyl modification:addition of acetic anhydride,0.3g/g protein, reaction pH8.0, reaction temperature 50℃,reaction time of 3hr, protein solubility up to 88.15%.4.Comparison of rice protein and modified rice proteinIn this study, combined with the enzyme alkaline extraction of rice proteins and phosphorylation, acylation of the modified rice proteins were Comparative Studies, found that modified rice proteins than non-modified rice proteins emulsification, foaming of, oil and water holding capacity and has better physical and chemical characteristics such as improved stability only sparkling little worse than the unmodified protein in the food processing in the application of practical significance. Modified rice proteins phosphorylated the physical and chemical properties that are superior to acetylation or succinylation modified rice proteins, therefore, the phosphorylation modification is more suitable for rice proteins of the chemical modification method.