Abstract

t has been generally supposed that parboiled rice has a greater nutritive value than raw rice and that even on polishing its antineuritic value s not lost considerably as with raw rice (McCarrison and Norris, 1924). ndeed, evidence has been presented to show that during parboiling, the endosperm absorbs vitamin B₁ at the expense of the germ and pericarp and hat therefore milling does not result in the removal of the vitamin to the same extent as with untreated rice (Douglas, 1930; Aykroyd, 1932; Ghosh ind Dutt, 1933 (Acton, Ghosh and Dutt, 1933; Codd and Peterkin, 1933). More recently, it has also been shown that parboiling results in a movement n part of the protein and mineral constituents originally present in the ileurone layers of the raw rice, into the interior towards the endosperm Sreenivasan and Das Gupta, 1938). The extent to which parboiling preser- res the essential nutritive constituents of rice on polishing depends however on the variety of rice and in particular on the thickness of its bran layer and he extent of parboiling (Subrahmanyan, Sreenivasan and Das Gupta, 1938). n commercial practice, only the coarser, the long-grained and the coloured varieties (which are generally classed as inferior) are used for parboiling. These have invariably thick bran layers (Ramiah, 1936) and contain more proteins and minerals than the white and smallgrained varieties (Sadasivan and Sreenivasan, unpublished data). Besides, since parboiling yields a coloured product even after some polishing and is largely consumed by the poorer classes, it is not generally polished to the same extent as raw rice. These two causes, together with the fact that parboiling toughens the grain xid hence makes the removal of the pericarp more difficult, are primarily Sponsible for the richness of commercial samples of parboiled rice in egard to both proteins and minerals as compared with the samples of raw rice available on the market.

Keywords: