Modification of functional properties of white and brown rice protein concentrates

Abstract

The aim of the study was a comparative characteristic of the functional properties of protein concentrates (PC) obtained from white and brown rice, modified by the addition of calcium citrate at the stage of protein deposition and proteolysis with a degree of hydrolysis of 3.89-4.16%. Optimal conditions of PC proteolysis with enzyme preparations of endoproteolytic (Protamex, Neutrase 1.5 MG) and combined endoproteolytic and exopeptidase action (Flavourzyme 500 MG) were determined. Substrate concentration was 25%, the concentration of enzyme preparation – 1.0 to 1.5 U/g protein, temperature 50-55 ?, pH 5,0-6,2, length 150-195 min hydrolysis showed that the functional properties higher the PC, derived from white rice than PC brown rice. Thus, the foaming capacity is higher by 5-6 times, but the stability of the foam in PC from brown rice was absent. PC obtained from both rice species with the addition of calcium citrate (PCC) at the protein deposition stage has lower functional properties than unmodified PC. In protein concentrates hydrolyzed by enzyme preparations (PHC), on the contrary, there was a higher solubility, water-binding, foaming ability, while the fat-binding ability and fat-emulsifying properties, on the contrary, were lower than in PC, not subjected to proteolysis. The foaming capacity of white rice PHC was equated to the foaming capacity of egg albumin (300%). Choosing, thus, a method of modification, proteolysis parameters and type of grain (white or brown rice), it is possible to adjust the functional properties of protein concentrates to select the direction of their use in order to stabilize technological processes of production and improve food quality.