Characterization and differentiation of monovarietal grape marc distillates on the basis of varietal aroma compound composition.

To investigate the varietal aroma compound composition of monovarietal grape marc distillates made from six different varieties (Vitis vinifera L.) in the region of Istria (Croatia), 30 samples were subjected to GC/MS and GC/FID analysis. A total of 73 compounds were identified: 45 monoterpenes, 20 sesquiterpenes, 3 diterpenes, and 5 C(13)-norisoprenoids. The largest number and the highest concentration of monoterpenes were found in Muscat Blanc, followed by Rose Muscat of Porec (Muskat ruza porecki) distillates, which were both characterized as highly aromatic. Lower, but still significant monoterpenol content was determined in distillates made from Istrian Malvasia (Malvazija istarska) grape marc. Chardonnay, Cabernet Sauvignon, and Teran distillates exhibited poorer monoterpene profiles, while Teran distillates contained elevated sesquiterpene concentrations. It was concluded that investigated monovarietal grape marc distillates significantly differ in varietal aroma compound composition. Stepwise linear discriminant analysis provided efficient discrimination models, and extracted various monoterpenes, sesquiterpenes and C(13)-norisoprenoids as important differentiators of distillates according to varietal origin.