THE DISTRIBUTION OF LYSINE,METHIONINE,VALINE AND THREONINE IN WHOLE RICE GRAIN IN RELATION TO THE DEGREE OF MILLING IN MODERATION / 营养学报

ABSTRACT

Whole rice grain was dissected by hand into fractions of pericarp, ale-urone, scutellum, embryo and endosperm. For the convenience of having enough amount of samples for amino acids assay some of which were recom-bined and finally three parts, pericarp +aleurone layer, scutellum + embryo and endosperm, were obtained. Protein, lysine, methionine, threonine and valine contents were determined for each part. The data obtained indicated that although total weight of the first two parts accounted for only 7.27-8.43% of the whole grain, they contributed 14.5-15.8% protein, 29.0-30.5% lysine, 11.8% melhionine, 16.8% valine and 19.4% threonine, contained in the whole grain. During husking process it indicated that the lesser amounts of pericarp, aleurone, scutellum and embryo were retained and the larger percentage of protein and lysine was lost. This fact was identified either by a specially designed miller in the laboratory or a commonly used sand wheel miller in the factory. The suitable degree of milling for rice was discussed and it was proposed that 92% extration for rice rather rational.