Fermentation-derived Aroma Compounds in Varietal Young Wines from South Africa

Abstract

The volatile composition of 925 single cultivar young Sauvignon blanc, Chardonnay, Pinotage, Merlot, Shiraz and Cabernet Sauvignon wines of vintages 2005 to 2007, was determined using gas chromatography -flame ionisation detection. Compositional data were compared to published data on young wines from South Africa and other countries. South African young wines analysed in this study had a largely similar volatile composition to that reported in the literature. Significant between-vintage and between-cultivar differences were observed in the volatile composition of the wines investigated in this study. The concentration ranges of four compounds in red wines, hexanol, propanol, diethyl succinate and ethyl lactate, and four compounds in white wines, 2-phenylethanol, hexanoic acid, isoamyl acetate and propanol, were not influenced by vintage effects. This finding was interpreted as the first indication that typical concentration ranges for some aroma compounds can be established for South African young cultivar wines. A trend was observed in the white wines that the alcohols and their respective acetate esters, as well as fatty acids and their ethyl esters, were responsible for the vintage-related effects. Differences in volatile composition between Chardonnay and Sauvignon blanc wines could also largely be explained on the same basis. Classification models were established to discriminate between individual red wine cultivars and between the two white wine cultivars and correct classification rates of respectively, 79 % and 85 % were achieved.

Evolution of aromatic compounds during the second fermentation and aging of Brazilian sparkling wine

“…The concentration of the seven volatile fatty acids identified in the samples were consistent with those previously reported [13,17], and most of them exceeded their respective olfative threshold values. Fatty acids are related to creamy, cheese and rancid notes, and at low concentrations give pleasant notes and contribute to the overall complexity of wines.…”

Differentiation of Commercial PDO Wines Produced in Istria (Croatia) According to Variety and Harvest Year Based on HS-SPME-GC/MS Volatile Aroma Compounds Profiling

“…Concentrations and the composition of wine major aroma compounds produced during fermentation, such as alcohols, straight-chain acids, and ethyl and acetate esters, were in a fair agreement with those found in the three varieties investigated earlier (22,23,30,31,51), and it was confi rmed that they make up a basis of the aroma profi le of unoaked young white wines. They depend mostly on fermentation parameters and conditions, although physicochemical composition of must may have a certain infl uence (52).…”

“…Several studies reported that fermentation aroma compound composition signifi cantly depends on varietal origin and harvest year, and can be useful in diff erentiating wines on the basis of these two criteria (7,37). This especially refers to medium-chain fatty acids and their ethyl esters which, unlike acetates, depend more on the availability of substrates, and therefore agricultural conditions and variety, than on enzymatic activity of yeast (31). For example, it was shown that South African unoaked young Chardonnay wines can be discriminated from other varieties (correct classifi cation of 74 %) on the basis of 2-phenylethanol, diethyl succinate, ethyl hexanoate, ethyl decanoate, ethyl octanoate, hexyl acetate and 1-propanol concentrations (31).…”

Volatile Compounds from Must and Wines from Five White Grape Varieties

“…The highest concentration of free fatty acids was observed in Vidal wine, where concentrations of hexanoic and octanoic acids reached 12.2 and 38.1 mg/L, respectively (Table 3). These values are relatively high compared to reported values for V. vinifera white wine with reported concentration ranging from 0.05 mg/L in Chardonnay to 13.7 mg/L in Sauvignon Blanc, for hexanoic acid, and from non-detectable to 12.2 mg/L in Sauvignon Blanc, for octanoic acid [42,43].…”