Effect of grinding action on the flowability of rice flour

Rice (Oryza sativa L.) is an important food crop in the world. Broken rice, either basmati or non-basmati varieties, is used to produce rice flour by milling. The effect of grinding on the flowability of rice flour was evaluated using flow indicators viz., aerated bulk density (0.63–0.79 g/cm3), tapped bulk density (0.77–1.03 g/cm3), angle of repose (38.10°–52.84°), frictional co-efficient, Carr’s index (11.26–33.11), and Hausner’s ratio (1.13–1.50); and instrumentally by powder flow analyser viz., cohesive index (12.17–19.07), caking strength and powder flow stability. Both, flow indicators and powder flow analysis showed that the flours from cyclone and stone mill were more cohesive while the free flowing nature was shown in flours ground in super mill. Moreover, the flours from hammer mill showed less cohesiveness (14.29–15.96) despite having irregular shape than the flours obtained from stone mill (16.77–19.07).