Some aroma compounds produced by vinous fermentation

Abstract

Various biochemical transformations involved in vinous fermentations are reviewed from the point of view of their formal ion of volatile aroma or flavor compounds in fermented beverages. In addition to the recently elucidated processes for the formation of aliphatic primary alcohols of molecular weight greater than that of ethanol, Nordström's mechanism for the formation of esters during fermentation is discussed. Experimental evidence supporting this mechanism in vinous fermentation is presented; the White Riesling grape is found to contain insignificant, quantities of esters while the wine prepared from these grapes, analyzed immediately after fermentation, shows relatively large amounts of several volatile esters. In addition, in an investigation of an older California sherry, ethyl acid malate is found to be nearly all the single isomer with the hydroxyl group on the carbon adjacent, to the free carboxyl group. This finding suggests an enzymatic (presumably vinous fermentative) production rather than simple chemical esterification in the wine after fermentation. An extension of Nordström's mechanism for ester production is proposed to explain the formation of certain secondary amides found in wines.