Study on Extraction of Deffatted Rice Bran Protein by Chemical Methods

Defatted rice bran was used to extract protein by alkali method，acid method and salt method，orderly.The yield of protein in defatted rice bran extracted was a key index.The optimal extraction processing parameters were determined by orthogonal experiments through evaluating the effects of material-liquid ratio，pH value，extraction time，temperature，salt concentration of each method on the yield of protein.The results from the alkali method indicated showed that the optimal parameters of defatted rice bran were 3 h，pH 13，35 ℃，material-liquid ratio of 1∶10，and the yield of protein was 24.3%.For the acid method used，the best extraction parameters was 3.5 h，pH 0.5，40 ℃，material-liquid ratio of 1∶8，and the best yield of protein was 18.18％.For the salt extraction method ，the optimal NaCl level，temperature，material-liquid ratio of defatted rice bran were respectively 0.6 mol/L，45 ℃，material-liquid ratio of 1∶10，2.5 h，and the yield of protein was 7.86%.For the total yield of protein in rice bran extracted was 48.23% under the optimal parameters of alkali method，acid method and salt method，orderly.