The Preparation Of Rice Bran Protein Isolate And Glutamine-enriched Bioactive Peptide

Rice bran Protein is a kind of vegetable protein with high nutritious. The compositions of its essential amino acid are balanced. And its low oversensitive make it fit for nutritious foods that served for children and old people. The rice bran is abundant and inexpensive. Exploiting the rice bran will enlarge the value of rice bran and offer the low oversensitive protein. So optimizing the extraction technology of rice bran protein is a meaningful thing. Gln is a conditionally essential amino acid (CEAA), which is necessary for some patients. Gln peptides will be full absorbed and they are stable and easy dissolved, while the monomer of Gln doesn't have those advantage. So the Gln peptides is the important source of Gln. This paper studied the extraction technology of rice bran protein from defatted rice bran, and determined the optimum conditions of the alkalinity method and the enzymatic method. Glutamine-enriched bioactive peptide was obtained by rice bran protein with protease, and determined the optimum conditions.(1) Extracted rice bran protein with alkali liquid. Extracting condition for the recovery rate of protein was optimized with the aid of odd factor tests and orthogonal experiments.The results showed that the optimum conditions for the extracting was at pH92.5,room temperature, and in liquid to solid ratio of 8 when 2.5 hours of extracting time was applied. On this condition, the recovery rate of the defatted rice bran protein could reach 77.68%, and the concentration of rice bran protein in the production could reach 80.14%. The recovery rate of the rice bran protein reached 67.45%, the concentration of rice bran protein in the production reached 71.23%.(2) Extracted rice bran protein with enzymes. Enzymatic condition for the recovery rate of protein was optimized with the aid of odd factor tests and orthogonal experiments. The results showed that the optimum conditions for the hydrolysis by Alcalase was at pH7.5, temperature 45℃, and in enzyme to substrate ratio (E/S)of 300u/g when 2 hours of hydrolysis time was applied. On this condition,the recovery rate of the defatted rice bran protein reached 80.23%; the concentration of rice bran protein in the production reached 74.84%. The recovery rate of the rice bran protein reached 71.23%,the concentration of rice bran protein in the production reached 66.84%.(3) Hydrolysis rice brain protein with protein enzymes. Targeting the content of Gln and DH, through odd factor tests and orthogonal experiments, the results showed that the optimum conditions for the hydrolysis by Alcalase was at pH10.5, temperature 45℃, and in enzyme to substrate ratio (E/S)of 4% when 20%[S] and 3 hours of hydrolysis time were applied. The content of Gln reached 14.6%. The protein yield reached 40.2%.