The Optimization Of Extraction And Functional Study On Rice Protein

Rice protein is one of the major dietary proteins, and has been reported to have some physiological functions as hypocholesterolemic effect, etc. Rice protein has its own protein components, in which glutelin and prolamin are major storage proteins. The extraction method is an important factor to modify the physiological function of rice protein. Thus, alkali- and enzymatic extraction may induce some differences on nutritents, flavour, and physiological function of rice protein, etc.Using the variety from Yanshou-Rice, the present study was conducted to investigate the optimum extraction of rice protein and the effects of different extraction process, alkaline andα-amylase, on conventional components of rice protein, rice protein composition, amino acid concentration and some physical functions, such as emulsifying properties, foaming properties, water and fat absorption. The siginficance of this study was to provide some evidences for further investigation on physiological function and deep processing technology of rice protein.Conclusion were drawn from this study as follow:The optimum condition of alkaline extraction, by which 90.01%rice protein was obtained,was solid-to-liquid ratio 1:9, extraction time 2h, alkali concentration 0.1mol/L and particle size 80;The optimum condition ofα-amylase extraction, by which 89.44% rice protein was obtained, was solid-to-liquid ratio 1:4, extraction time 7 h, dose ofα-amylase 0.4 g and particle size 80;Glutelin was the crucial composition in rice proteins extracted by alkali-andα-amylase. No differences of purity, protein component, essential- and non-essential amino acids comcentration were observed in rice proteins extracted by alkali- andα-amylase (P > 0.05). Aikali extraction significantly reduced sulfur-containing amino acids level (P < 0.05), whereas the concentrations of lysine and arginine were both increased by alkaline (P < 0.05), in comparison toα-amylase.