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H. KUMAGAI, Dept. of Agricultural and Biological Chemistry, Nihon Univ., 1866 Kameino, Fujisawa-shi, 252-8510, Japan Volatile sulfur compounds often characterize a certain food material by their specific flavor. However, most of these flavor compounds do not exist in the raw material, but are hidden in the flavor precursors in larger molecular size without having any specific smell. When the material is cut or crushed during cooking, the flavor precursors are converted into volatile flavors by enzymes. As for garlic, S-alk(en)yl-L-cysteine sulfoxides such as S-allyl-L-cysteine sulfoxide and S-methyl-L-cysteine sulfoxide are converted mainly into sulfides such as diallyl disulfide and allyl methyl disulfide by C-S lyase. Some of these sulfides not only characterize the garlic flavor but also have the inhibitory effect against platelet aggregation. The inhibition site has been specified to be cyclooxygenase in the arachidonic-acid cascade. As for shiitake mushroom, lentinic acid is converted into cyclic sulfur compounds such as lenthionine by γ-glutamyl transferase and C-S lyase. Lenthionine is the key flavor compound of shiitake mushroom. Since the formation of flavor from shiitake mushroom is similar to that from garlic, we examined whether the sulfur compounds from shiitake had the inhibitory activity against platelet aggregation. Platelet aggregation induced by arachidonic acid and U-46619, the analog of thromboxane A2, was inhibited by the essential oil from shiitake that contained lenthionine as a major sulfur compound. This result indicates that the inhibitory site of the shiitake flavor is different from that of garlic flavor. As for wasabi, Japanese horseradish, glucosinolates are converted mainly into isothiocyanates such as allyl isothiocyanate and 6-methylthiohexyl isothiocyanate by myrosinase. We found ω-methylthioalkyl isothiocyanate had stronger inhibitory activity than ω-alkenyl isothiocyanate. All these findings suggest that the volatile sulfur compounds from these culinary spices not only provide specific flavors and stimulate our appetite but also inhibit platelet aggregation and prevent thrombosis.
Session 10, Natural antioxidants in herbs and spices
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |