Electrophoretic Characterization and Functional Properties of Rice Proteins from Indian Rice Cultivars

Rice protein isolates and extracts of protein fractions were prepared from Indian rice cultivars, namely, Jaya, HKR-120, P-44, Sharbati, Bas-370, and HBC-19. The protein extracts were characterized using SDS-PAGE. The total protein contents of rice cultivars ranged from 5.46 to 7.02 g/100 g sample with albumin and glutelin fractions showing the highest variability among rice cultivars. The electrophoretic patterns of protein fractions exhibited many varietal differences with glutelin fraction revealing the most heterogeneous (10–17 polypeptide units) and prolamin fraction revealing the most homogenous polypeptide composition (3 polypeptide units). The alkali extracted rice endosperm protein isolates showed favorable emulsifying and foaming capacities particularly at an alkaline pH of 11. The total protein content was significantly correlated positive with foaming capacity (r = 0.917, p < 0.01) and negative with oil absorption capacity (r = −0.914, p < 0.05). The total protein content was also correlated significantly positive with cooking time (r = 0.956, p < 0.01) and cooked grain hardness (r = 0.966, p < 0.01).