Terpene content of wine from the aromatic grape variety 'Irsai Oliver' (Vitis vinifera L.) depends on maceration time

Abstract

This study deals with the determination of the content of both free and bound terpenes in berries and wine of the aromatic grapevine variety 'Irsai Oliver'. Grapes were macerated in juice for different time intervals (viz. 0; 5; 12; 24 hours) and thereafter processed to wine. The objective was to map the dependence of some selected terpenes on the period of maceration. Using gas chromatography, some nine organic compounds were detected. Attention was paid to contents of linalool (3,7-dimethylokta-1,6-dien-3-ol), 2,6-dimetyl-3,7-octadiene-2,6-diol, hotrienol ([(5E)-3,7-dimethylocta-1,5,7-trien-3-yl] acetate), αterpineol (2-(4-Methyl-1-cyclohex-3-enyl)propan-2-ol), β-citronellol (3,7-Dimethyloct-6-en-1-ol), nerol ((Z)-3,7-dimethyl-2,6-octadien-1-ol), geraniol ((trans)-3,7-dimethyl-2,6-oktadien-1-ol) and epoxylinalool (2-(5-ethenyl-5-methyloxolan-2-yl)propan-2-ol): epoxylinalool 1 (trans-linalool oxide (furanoid) cis-linalool oxide (furanoid)) and epoxylinalool 2 (trans-linalool oxide (pyranoid) cis-linalool oxide (pyranoid)). Some basic wine parameters (alcohol, pH, sugars and total acids) were estimated as well. The terpene content in wine increased gradually with the period of maceration. The highest and the lowest amounts of terpenes were recorded after 24 hours of maceration and no maceration, respectively. The terpene glycosides content was higher than that of the aglycones. Linalool and 2,6-dimetyl-3,7-octadiene-2,6-diol were the most abundant terpenes. Based on the results of this study it is possible to conclude that the 'Irsai Oliver' variety of grape has a very high terpene content. To improve the aromatic profile of the wine, the grape must should be macerated for 24 hours.