Variations in lipid content and fatty acid composition of major non-glutinous rice cultivars in Japan

Lipid content and fatty acid composition of the major non-glutinous rice cultivars in Japan were analyzed over a 4-year period. The effects of crop year on lipid and fatty acids contents, except for heptadecanoic acid, were statistically significant. Annual mean temperature was negatively correlated with latitude. Myristic, palmitoleic, stearic, and oleic acids were negatively correlated with latitude, and linoleic and linolenic acids were positively correlated with latitude. Negative correlations were observed between stearic and linoleic acids, between stearic and linolenic acids, between oleic and linoleic acids, and between oleic and linolenic acids. Linoleic acid was correlated positively with linolenic acid. Thus, fatty acid composition appears to be influenced by temperature during the ripening stages. Especially, the amount of polyunsaturated fatty acids decreased with increasing temperature during the ripening stages. However, in Akitakomachi, fatty acid composition did not seem to be influenced by temperature.