Oxylipin Metabolism in Soybean Seeds Containing Different Sets of Lipoxygenase Isozymes after Homogenization

The oxylipin metabolism was analyzed in soybean homogenates containing different sets of lipoxygenase isozymes (L-1, -2, and -3); namely, Suzuyutaka (containing L-1, -2, and -3), Yumeyutaka (containing only L-1), Kanto102 (containing L-2), Kyushu119 (containing L-3), and Ichihime (lacking all three isozymes). The amount of oxidized fatty acids in the esterified form was higher than that in the free form with every cultivar. Kanto102 formed the highest amount of oxidized lipids, and Yumeyutaka and Ichihime formed the lowest. With Kanto102 and Kyushu119, high amounts of keto fatty acids were formed, while they were undetectable with Yumeyutaka and Ichihime. Due to the lack of lipoxygenases in Ichihime, an accumulation of free fatty acids was expected; however, their amount in Yumeyutaka was significantly lower than was expected. It is suggested that a pathway existed to form C6-volatiles through hydroperoxides in the esterified form.