Effect of stabilization of rice bran on the extractability and recovery of proteins

Abstract

Abstract The extractability profile of rice bran proteins under different conditions were studied to determine optimal conditions of extraction. Milling and differential sieving of rice bran increased the protein content in fine fraction by 7%. Maximum extractability of protein from defatted rice bran at pH 11.0 was 72%, out of which 70% could be precipitated at isoelectric pH 4.0. Increasing the time of extraction or using sodium chloride, sodium dodecyl sulfate or sodium hexametaphosphate were not effective in extracting more protein. The extraction and precipitation profiles of proteins from acid stabilized rice bran were comparable to untreated rice bran. However, it was very low for heat stabilized and parboiled rice bran. Denaturation of protein due to heat treatment affected the extractability of protein. Protein contents of protein concentrates obtained from untreated rice bran and acid stabilized rice bran were in the range of 71–73% whereas protein concentrates from heat stabilized rice bran and parboiled rice bran had lower protein contents of 39.5 and 54.5%, respectively.