Development of lightly milled black rice with easy cooking and retaining health benefits.

Abstract

Consumers are reluctant to eat pigmented rice due to cooking difficulties and harder texture than white rice. In this study, paddy samples of black rice (Hom Nil cultivar) were milled for 0, 10, 30, 60 and 100s and degree of milling (DOM) ~ 0, 6, 12, 22 and 30% were obtained. Head rice yield, physicochemical properties, cooking qualities, nutrients, resistant starch content, antioxidant properties, and sensorial qualities were studied. Milling at 10s (DOM ~ 6%) did not remove all bran fractions. Head rice yield retained at 70.33%. Lightness (L*) and redness (a*) of black rice remained constant until DOM ~ 20% but yellowness (b*) gradually increased. Nutrients were embedded at different locations in grain kernels. All nutrients decreased with DOM but in different extents. Milling at 10s generated loss of anthocyanin (70%), fat (44%), ash (33%) and phenolic compounds (31%). Comparably tiny losses were observed in protein (15%) and dietary fiber (25%). However, cooking qualities of black rice were substantially improved. Cooking time reduced from 22 to 15min with increases in water uptake ratio and volume expansion ratio. Additionally cooked black rice had impressively softer texture. Panelist appreciated the change in odor, flavor, texture attributes and palatability of the rice.