Effect of parboiling method on the physical properties of parboiled paddy

Abstract

Some important physical properties of paddy necessary for designing grain processing equipment namely, size and shape, thousand grain weight, bulk density, true density and angle of repose at moisture content of about 15% d.b. for raw paddy LD 365, a red rice variety were determined. These properties were also determined for the same variety of paddy after parboiling using cold soaking method at moisture content of about 29% d.b. and using hot soaking method at moisture content of 17% d.b. When comparing raw paddy, cold soaked paddy and hot soaked paddy, the thousand grain weight varied as 15.56g, I6.47g and 15.32g respectively. Bulk density was 585.92, 576.4 and 539.32 kg/rn respectively where, true density was 1183.61, 1177.32 and 1097.92 kg/m* respectively. Porosity varied as 50.50%, 51.04% and 50.88% and the variation of angle of repose WAS as 33.6<f, 39.24° and 38 070 respectively.