Studies on Palatability of Rice in Northern Kyushu VII. Locational differences in palatability of rice and its related factors

The palatability and physiochemical properties of milled rice produced on different types of soils and latitudes were studied in order to improve the culture technique to produce good eating quality rice. There was locational difference, we found that the differences in soil types had a great influence on palatability. No clear relationship between the altitude and palatability was found. The palatability of rice produced on Light-colored Andosols (LAN) was inferior to that of rice produced on other soil types : Fine-textured Yellow soils, Fine-textured Brown Lowland soils, Gravelly Gray Lowland soils. The protein content of rice produced on LAN was significantly higher than that of rice produced on other soil types. Protein content was significantly correlated with the palatability using rice grown in various locations. On the other hand, amylose content and amylographic characteristics were not related to palatability. The results lead to the conclusion that the main cause of the deterioration of palatability of rice grown in LAN was increases in protein content due to increases in nitrogen released from LAN during the late stage growth period of rice plant. Therefore, it is important to restrict the amount of nitrogen absorbed by rice plant i.e., improvement of the method of fertilizer application and soil improvement, in order to improve the eating quality of rice grown in LAN.