RELATIONSHIPS BETWEEN THE DURATION OF ORG ANIC FARMING CULTURE AND AMYLOGRAPHIC CHARACTERISTICS AND MINERAL CONTENTS OF RICE

The amylographic characteristics of milled rice and mineral contents ( including nitrogen) of brown rice, which were produced under an organi c farming culture (no chemical ferilizers, all of the rice residues re turned to the paddy fields) were determined for 1 to as long as, 16 ye ars. The maximum viscosity and breakdown values of rice flour increase d with increasing duration of the organic farming culture. The content s of minerals in the rice grain; produced one year after the beginning of organic farming culture, were similar to those of the rice from a customary farming culture. The N, P and K contents decreased with the duration of organic farming culture; but the Mg content increased grad ually. These changes in the contest of the elements were the greatest during the first 5 years. The Mg/K ratio, which is thought to be a sui table index of the eating quality of cooked rice, gave significant cor relations with both the maximum viscosity and breakdown values. These results suggested that the eating quality of cooked rice by organic fa rming culture was better due to increases of rice starch stickiness an d of the Mg/K ratio.