Higher Alcohols and Esters Formed from Yeasts

1 HIGHER ALCOHOLS AND ESTERS FORMED FROM YEASTS 

The main volatiles in wines are the higher aliphatic alcohols, ethyl esters, and acetates formed from yeasts during fermentation. Acetates are very important flavors characterized by fruity notes, C4-Ci0 fatty acid ethyl esters manly confer fruity scents to the wine. Other wine aroma compounds are C6 alcohols, such as 1-hexanol and cis- and trans-3-hexen-l-ol, 2-phenylethanol, and 2-phenylethyl acetate. Contents of these compounds in wine are linked to the winemaking processes used fermentation temperature, yeast strain type, nitrogen level in must available for yeasts during fermentation, clarification of wine (Rapp and Versini, 1991). Much literature on the wine aroma compounds was reported in reviews by Schreier (1979) and Rapp (1988). 

Analysis of volatile compounds in wine is usually performed by gas chromatography (GC) coupled with flame ionization (FID) or GC/ 

Mass Spectrometry in Grape and Wine Chemistry, by Riccardo Flamini and Pietro Traldi 

The first methods of sample preparation were performed by liquid-liquid extraction using solvents, such as dichloromethane/ pentane 2 1 (v/v), Freon 11, or a Freon 11-dichloromethane 9 1 (v/v) mixture (Drawert and Rapp, 1968 Hardy, 1969 Rapp et al, 1978 Marais, 1986). Alternatively, liquid-liquid discontinuous extraction with l,l,2-trichloro-l,2,2-trifluoroethane (Freon 113 or Kaltron), was proposed (Ferreira et al., 1993 Rapp et al, 1994 Genovese et al., 2005). 

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