Formation and Occurrence of Flavor Compounds in Wine and Distilled Alcoholic Beverages

The most probable mechanisms involved in the formation of carbonyl compounds, fusel alcohols, fatty acid esters, and free fatty acids by yeast in fermentation are discussed. Isopentyl alcohol, phenethyl alcohol, and their acetates in addition to the ethyl esters from hexanoate to laurate formed by different yeasts in sugar fermentation were determined. The bivariate distributions of the concentrations indicate that the mutual relationships of the compounds depend significantly on the yeast used and on the capacity of the yeast to produce alcohols and esters. The wine yeast used in this work produced smaller amounts of ethyl esters of fatty acids from acetic acid to octanoic acid under aerobic fermentation conditions than under strictly anaerobic conditions; on the other hand, ethyl laurate and ethyl 9-hexadecenoate were formed more abundantly in anaerobic conditions. Furthermore, qualitatively-similar flavor compositions were obtained in a Spanish sherry and a Finnish berry wine of sherry type. Hence, the formation of the most dominant compounds occurring in beverages depend more on the yeast selected than the raw materials used in fermentation.