Effect of processing paddy on digestibility of rice starch by in vitro studies

Paddy (Oryza sativa L) (variety ‘IR — 64’), was parboiled, puffed by sand roasting and flaked by edge runner and roller flaker and variations in physical and physicochemical properties were studied. Moisture contents were lower (5.8–10.8%) in processed rice products compared to raw materials (11.8%). Ratio of rice to sand in the case of puffed rice preparation was optimized. The equilibrium moisture content was 27.4% in raw rice while it was much higher (38.9–81.0%) in processed rice. Sedimentation volume was lowest (6.2 ml) in raw rice and highest (18.8 ml) in popped rice. Starch content was 84.8 and 76.5–83% in raw and processed rice, respectively. In vitro starch digestibility was highest in roller flaker flakes and lowest in raw milled rice. Among the ready to eat products, popped rice showed least starch digestibility (∼30%).