EFFECT OF SOYBEAN LIPOXYGENASE ON SENSORY TASTE OF TOFU

In order to evaluate the effect of lipoxygenase (LOX) on the sensory t aste of tofu, relationships between the contents of several components (protein, total lipids, free sugars, isoflavones, total carbonyl comp ounds and hexanal) and the sensory taste of tofu made from normal or L OXs-deficient soybean cultivars were investigated. The tofu made from Suzuyutaka (normal cultivar) tasted sweeter and more mouthful (rich) c ompared with those from LOX-2, 3-deficient Yumeyutaka and LOX-1, 2, S- deficient Ichihime. No difference in the degree of undesirable taste c ould be detected among the tofus made from the three soybean cultivars by panel. The three different tofus were similar in their contents of protein, total lipids, free sugars (sucrose, stachyose, raffinose, gl ucose) and isoflavones. The total carbonyl compounds and hexanal conte nts in the tofu of normal soybean Suzuyutaka were much more than those of LOXs-deficient soybeans (Yumeyutaka and Ichihime). These results s uggest that oxidation products of unsaturated fatty acids by LOX contr ibute to the mouthfulness (richness) for the taste of tofu, and streng then sweetness in the presence of free sugars by contrast effect.