Protein fractions were extracted according to the Osborne method. Rice protein samples were extracted twice with distilled water for 60 min at 25 °C. After centrifugation of each extract at 3000g for 30 min, the supernatant was used for the determination of the water-soluble protein, albumin. The residue was then extracted successively in a similar manner with 5% NaCl, 70% ethanol and 0.05 M NaOH. The supernatants of each extract were collected separately and used to estimate the salt- (globulin), alcohol- (prolamin) and alkali- (glutelin) soluble fractions. Albumin, globulin and glutelin were concentrated by isoelectric sedimentation at pH 4.1, 4.3 and 4.8, respectively, while prolamin was concentrated by evaporation. Residue remaining after the successive extractions corresponded to the insoluble proteins. Each fraction was collected and lyophilized by a lyophilizer (ACPHA1-4, CHRIST, Germany). The protein content of each fraction was determined by the Kjeldahl method (total nitrogen × 5.95)