Parboiling Treatment of Rice

Abstract

THE pre-milling treatment of paddy known as parboiling, involving treatment of the unhulled rice with hot water and steam, is established commercial practice, and for some time considerable attention has been paid to this and similar methods which aim at improving the nutritive value of rice; these latter include 'conversion' processes in which the steam is applied under pressure, sometimes preceded by a stage when the paddy is held under partial vacuum. Reviews of the subject have been prepared by the Economic Advisory Council, London¹, and the U.S. National Research Council, Washington². These treatments result in a higher content of water-soluble nutritional factors, particularly those of the B group of vitamins, in the milled rice. It has been generally accepted that this is due to a redistribution of the nutrients within the grain, so that the endosperm is considerably enriched.