Formation by mechanical stimulus of the flavor compounds in young leaves of Japanese pepper (Xanthoxylum piperitum DC.)

The volatile compounds formed in slapped and crushed young leaves of Japanese pepper (Xan-thoxylum piperitum DC.) were compared with those of intact leaves by using a dynamic headspace gas analysis combined with CC-MS in an on-line system, together with the results of a sensory evaluation. The results indicated that the factors influencing the aroma note were mainly the constituent oxygenated monoterpenes and C-6 compounds and the quantity of terpene hydrocarbons. To clarify the formation mechanism for the aroma, the activities of lipoxygenase and beta -D-glucosidase were investigated. The results revealed that the hydrolysis of glycosides and the degradation of unsaturated fatty acids both played an important role in the formation of the major aroma compounds in young leaves of Japanese pepper.