Evaluating the Processing Parameter of Milling, Cooking and Thermal Properties on Selected Varieties of Rice in Ebonyi State, Nigeria

Abstract

Nigeria farmers are rice producers growing many varieties and prone to accepting any new varieties with seemingly better grain yield and qualities. This study analyzed the quality aspects of milling, cooking and thermal properties of selected rice varieties. Ten paddy rice varieties were processed to raw rice and analyzed for their milling, cooking and thermal properties. The results shows that IWA 7 had the highest head rice yield and least broken grain while IWA 8 had the least head rice yield and highest broken grain. Agreement and Argwula had the highest total milling yield while IWA 1 had the least. IWA 2 had the highest brown rice while Argwula had no brown rice. There were no unmilled grains and stones were found only in Argwula and IWA 3 varieties. Faro 52 had the highest immature and no chalky grain. The gelatinization temperatures were intermediate. Agreement had the highest percentage of amylose content while Faro 44 had the lowest. The volume expansion ranged from 1.5 to 7. The thermal conductivity values ranged from 0.332 to 0.354 WmoC, the specific heat capacity values ranged from 3.44-3.89 kJ/kg oC and thermal diffusivity ranged from 0.75 to 0.80m2/s. Varieties with higher amylose content required a shorter cooking time. This makes IWA 6 and Agreement the varieties with the best cooking quality. Thermal properties were good for all the varieties and the rice grains exhibit the ability to retain heat better than other existing varieties. Keywords: Rice Varieties: Amylose: Parboiling: Specific Heat Capacity: Rice Grain Quality