Physical Properties of Raw and Parboiled Paddy

Abstract

The physical properties namely, size and shape, bulk density, true density, and angle of repose at moisture contents ranging from 7·19 to 28·28% d.b. for raw paddy (IR-36) and from 12·24 to 43·53% d.b. for parboiled paddy were determined using standard techniques. In the case of raw paddy, the thousand grain weight increased from 23·04 to 27·16 g with an increase in moisture content from 10·45 to 32·13% d.b. Bulk density and angle of repose increased from 522 to 566 kg/m 3 and 42·35 to 49·30°, respectively, with an increase in moisture content from 7·19 to 27·86% d.b. True density and porosity decreased from 1405 to 1348 kg/m 3 and from 62·84 to 58·01% respectively, with an increase in moisture content from 7·19 to 27·86% (d.b.). In the case of parboiled paddy, bulk density and angle of repose increased from 507 to 564·8 kg/m 3 and 39·90 to 43·89°, respectively, with an increase in moisture content from 12·24 to 43·53% d.b. True density and porosity decreased from 1411 to 1342 kg/m 3 and from 64·08 to 57·91% respectively, with an increase in moisture content from 12·24 to 43·53%. The physical properties were linearly dependent upon moisture content.