engleski

Analysis of aroma of white wine (Vitis vinifera L. Pošip) by gas chromatography-mass spectrometry

Aroma of wine is influenced by many factors such as grape variety, viticulture practices and especially applied enological treatments during wine production and aging. Most of the aroma compounds are synthesized during the alcoholic fermentation, as secondary yeast metabolites. Different yeast strains contribute differently to the complexity of wine aroma. Also, final wine aroma is influenced by chemical reactions that occur during aging of wine, primarily oxidation and hydrolysis. The objective of this study was to determine the influence of yeast strain along with antioxidant addition (sulfur dioxide and glutathione) on aroma and sensory properties of Pošip wine. Wines were produced either by spontaneous alcoholic fermentation (indigenous yeasts) or by inoculation of commercial Saccharomyces cerevisiae yeast strain. Sulfur dioxide and glutathione were added to wines at the bottling, and analyses were carried out after 12 months of aging. Esters, higher alcohols, fatty acids, terpenes and norisoprenoid were analyzed by solid-phase microextraction coupled with gas chromatography mass spectrometry (SPME-GC/MS), while varietal thiols were first selectively extracted and concentrated by p-hydroxymercurybenzoate and strong anion exchange column prior to GC/MS analysis. The results showed that spontaneous alcoholic fermentation resulted in higher concentrations of some esters (i-amyl acetate, ethyl octanoate and ethyl decanoate), alcohol (phenylethyl alcohol) and terpene (α-terpienol) while commercial yeast strain influenced on higher concentrations of ethyl-2-methylbutyrate, C6 alcohols and varietal thiols. Wine storage with higher concentrations of sulfur dioxide and glutathione after 12 months resulted in higher concentrations of most of analyzed aroma compounds. The sensory analysis results showed similar trend to those obtained by GC/MS: higher varietal thiols intensities were determined in wines fermented by commercial yeast strain and bottled with addition of sulfur dioxide and glutathione.

wine aroma, yeast strain, antioxidants, Pošip, sensory analysis

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