Volatile compounds in the production process of Croatian traditional sweet wine Prošek

The aim of this work was to identify and quantify the basic volatile compounds during the experimental production steps of sweet wine Prosek from the cv. Posip: (i) drying of grapes, (ii) alcoholic fermentation, and (iii) ageing for 6 months after the fermentation. Gas chromatograph (GC) with flame ionisation detector (FID) and headspace (HS) was used in this study. For the preparation of samples, SPME was applied. Significantly higher concentrations of acetaldehydes, some higher alcohols, ethyl acetate, ethyl hexanoate and ethyl decanoate were determined in dried grapes than in the grapes at technological maturity. In the 6-month-old Prosek, an increase of acetate esters (ethyl acetate, isoamyl acetate and 2-phenyl ethyl acetate) was observed, as well as the increase of other ethyl esters (ethyl lactate, ethyl hexanoate, ethyl octanoate and ethyl decanoate), out of which 2-phenyl ethyl acetate, ethyl lactate and ethyl octanoate have not been identified in the grapes at technological maturity and after the off-vine grape drying process.