Fatty Acid Composition of Rapeseed Oils of Japanese Old Type Varieties

Abstract

Rapeseed oils from Japanese old type rapeseed varieties are rich in erucic acid. Rapeseed oil with high erucic acid content is said to be harmful in nutrition. Therefore, rapeseeds with low content or whithout erucid acid have been developed in Japan and many countries of the world. The fatty acid composition of rapeseeds of Japanese old type varieties was examined. Main fatty acid composition of Towada rapeseeds grown in Aomori prefecture in 1982 was as follows: Oleic acid, 16%; linoleic acid, 13%; linolenic acid, 8%; icosenoic acid, 10% and erucic acid, 45%. The fatty acid composition of the same rapeseeds in the same area in 1983 was similar to that in the previous year. The fatty acid composition of Oomi rapeseeds grown in Kagoshima prefecture in 1982 was similar to that in Aomori prefecture in same year. Of the twelve old type varieties of rapeseeds which were grown in Iwate prefecture, eleven contained erucic acid in seeds oils at levels ranging from 42 to 49% and oleic acid from 11 to 17%. There was a negative correlation between percentages of erucic and oleic acids. There was a linear relationship (r=0.795) (1) between oleic (Y) and erucic (X) acids percentage, except for 'Aomori-1'.
Y=(-0.7246X)+47.24(1)
There was also a linear relationship (r=0.847) (2) between percentages of oleic (Y) and erucic (X) acids in all rapeseeds analyzed and reported data.
Y=(-0.4348X)+34.25(2)