Temporal development of sesquiterpene hydrocarbon profiles of different grape varieties during ripening

To investigate the profiles of sesquiterpene hydrocarbons in grape berries at different developmental stages several cultivars of Vitis vinifera (Gewurztraminer, Riesling, Yellow Muscat, Shiraz, Lemberger, Cabernet Sauvignon) were analysed during ripening. Therefore, HS-SPME-GC-MS measurements were performed with intact grape berries. The measurements demonstrated that grapes emit numerous sesquiterpene hydrocarbons and that the sesquiterpene profile exhibits a characteristic profile, depending on the variety and the developmental stage. In particular, bicylic sesquiterpenes with a cadinane backbone increased during ripening, while acyclic sesquiterpenes such as (E,E)-a-farnesene decreased, except for Gewurztraminer which shows increasing amounts of acyclic sesquiterpenes towards harvest. Furthermore, the profiles of the emitted sesquiterpenes differed significantly. In particular, Gewurztraminer possessed remarkably high amounts of (E,E)-a-farnesene, (3E,6Z)-a-farnesene and (E,E)-methylfarnesoate, while the sesquiterpene profiles of Riesling, Lemberger, Shiraz and Yellow Muscat were dominated by bi- and polycyclic sesquiterpenes. Cabernet Sauvignon showed only minor profile changes during ripening and its comparatively low sesquiterpene hydrocarbon amounts were dominated by (E)-beta-caryophyllene, a-humulene and an unidentified sesquiterpene. Copyright (C) 2012 John Wiley & Sons, Ltd.