Extraction And Application Of Rice Bran Protein By Ultrasonic-assisted Dual-enzymatic

Rice bran is a major by-product of rice processing, accounting for6%~8%of rice. Ricebran contains64%of the active substances, including nutrients fat, protein, carbohydrates,minerals, dietary fiber, etc., is the essence of rice. Rice bran protein content between12%to20%. Rice bran protein kinds of essential amino acid, amino acid composition close to theFAO/WHO recommended mode. Nutritional characteristics and value of rice bran protein andegg protein may be comparable.Another advantage of the rice bran protein is hypoallergenic.Rice bran protein is known allergenic protein lowest in grain protein, is widely used in theproduction of infant food. The utilization of rice bran in our country is still in its initial stage,and far abroad, most of our rice bran used for animal feed, serious waste of resources. So, howfull and effective use of rice bran resources, rice bran added to improve the practicalsignificance.In this study, defatted rice bran was used for the study, using ultrasonic-assisteddual-enzymatic extraction of rice bran protein, alkaline extraction and functional properties ofrice bran protein compared, and analyzed by SDS-PAGE electrophoresis, amino acid analysisand DSC analysis. Finally, use the chitosan to precipitated rice bran protein from the supernatantand used in ice cream. This is not only makes full use of the rice bran resources, and greatlyimprove the added value of the rice bran resource. The main results of this paper are as follows:1. Use the ultrasonic-assisted dual-enzymatic extraction of rice bran protein. In this study,Plackett-Burman and response surface analysis were used to optimized the ultrasonic-assisteddual-enzymatic extraction of rice bran protein, rice bran protein extraction rate as the responsevalue to determine the process conditions: ultrasonic time20min, ultrasonic power220W,α-amylase hydrolyzing temperature57℃, α-amylase hydrolyzing time1.5h, α-amylaseenzyme dosage40U/g, Alcalase2.4L hydrolyzing temperature51℃, Alcalase2.4L hydrolyzingtime1.5h, the amount of Alcalase2.4L600U/g. Under the above-mentioned conditions theextraction rate of rice bran protein was80.83%.2. Measured the solubility, emulsifying capacity and emulsion stability, foaming capacityand foam stability, oil-absorbing capacity, water-binding capacity of ultrasonic-assisteddual-enzymatic extraction of rice bran protein and alkaline extraction of rice bran proteinrespectively.3. The ultrasonic-assisted dual-enzymatic extraction of rice bran protein and alkaline extraction of rice bran protein were analyzed by SDS-PAGE respectively. Alkaline extraction ofrice bran protein had distribution probably in65.46kDa,46.77kDa,33.42kDa,23.66kDa,13.09kDa,8.07kDa and2kDa, ultrasonic-assisted dual-enzymatic extraction of rice bran proteinhad distribution mainly in2kDa. It can be seen, after dealing with ultrasonic and protease, ricebran proteins macromolecules into small molecules of proteins.4. Two methods of extraction of rice bran protein were analyzed by amino acid analysis.The results showed that ultrasonic-assisted dual-enzymatic extraction of rice bran protein andalkaline extraction of rice bran protein were isolated from17kinds of amino acids. Twomethods of extraction of rice bran protein, the amino acid composition and the main amino acidsof glutamate, aspartate and arginine are consistent, but amino acid content there are somedifferences.5. Respectively, ultrasonic-assisted dual-enzymatic extraction of rice bran protein andalkaline extraction of rice bran protein were analyzed by DSC. The results showed that thedenaturation temperature of the two rice bran protein were75.83℃and76.75℃. Two methodsof extraction of rice bran protein thermal denaturation temperature is very close.6. Using chitosan to recovery from the supernatant by ultrasonic-assisted dual-enzymaticextraction of rice bran protein, rice bran protein precipitation rate as the evaluation indexes,through the single factor and orthogonal experiment to determine the precipitation conditions:chitosan amount40mg/100mL supernatant, pH3.5, temperature60℃, time40min.At thismoment, the precipitation rate of rice bran protein was83.29%.7. The rice bran protein was used in ice cream developed. By single factor and orthogonalexperiment to optimize the best recipe for rice bran protein ice cream. The results showed thatthe best recipe is: soft sugar12%，dextrin5%，milk powder8%，cream3%，rice bran protein4%，monostearin0.4%，CMC-Na0.2%，gelatin0.2%。Under these conditions，the productionof soft ice cream taste lubrication，even delicate tissue state.