岡山県における主要水稲品種の食味と理化学的特性

The palatability and physicochemical properties of cooked rice, in the cultivars Koshihikari, Hinohikari, Asahi and Akebono, which are commonly cultivated in Okayama prefecture were compared with standard cultivar Nipponbare, in the paddy fields of Okayama, Hachihama and Kurashiki Farm of Okayama University. The rate of fertilizer application on those properties in Okayama Farm was also examined. Hinohikari beat the other four cultivars in all tests of palatability. Asahi tested better than Koshihikari, and was harder than Akebono, but in overall eating quality and stikiness it was almost indistinguishable from Koshihikari. The palatability values of cooked rice produced at Kurashiki farm, in which fertilizers were not applied for 25 years, were the highest out of the three locations. It was considered that the protein content of milled rice was lowest in Kurashiki due to the lower nitrogen content of the soil there. In all cultivars the higher the application rate of fertilizer, the lower the values of palatability due to the increase in nitrogen content of the milled rice, but not with amylose content or amylographic characteristics, i.e., maximum viscosity and breakdown values. The textural characteristics, i.e., the ratio of hardness/stichiness and hardness/adhesiveness were negatively correlated with overall eating quality. The results suggested that it is important to create manuals for the production of rice with good eating quality at each location in consideration of the nitrogen content of milled rice and the yield of brown rice.