Identification of Volatiles in Grape Musts and Characteristic Terpenoid Constituents

To clarify the volatile constituents, particularly the monoterpenoids, and the aroma characteristics of grapes, 4 varieties (Koshu, Zenkoji, Muscat of Alexandria and Muscat of Humbourg) were used in the present investigation. Forty four volatiles identified in Koshu must included all the 39 volatile components found in Zenkoji must. Terpinen-4-ol and linalool as monoterpenoids were detected in Koshu must, while only terpinen-4-ol was found in Zenkoji must. The content ratios of these monoterpenoids to the total volatiles were about 3% in Koshu and 0.8% in Zenkoji.

On the other hand, 18 volatile monoterpenes were found in each of the muscat grapes, although terpinen-4-ol was not detected. The content ratios of the monoterpenes to the whole volatiles were approximately 33% in Muscat of Alexandria and 35% in Muscat of Humbourg grapes. Large differences of the monoterpenoid constituents were recognized in the flavor of grape musts and suggest the characteristic of the grape varieties.