Relationship between volatile aroma compounds and sensory quality of fresh grape marc distillates

Abstract

To investigate possible relationships, the volatile aroma compound composition of 30 grape marc distillates obtained from six varieties was correlated with the sensory scores for basic properties (clearness, odour and taste) obtained by sensory testing using the hedonic German DLG model. High negative Pearson's correlation coefficients were determined between total concentrations of long-chain ethyl esters and the scores for the property clearness. Strong positive correlation of middle-chain fatty acids and their ethyl esters, and strong negative correlation of sesquiterpenes, diterpenes, methanol, C6-alcohols, acetic and short-chain fatty acids, long-chain ethyl esters, ethyl acetate, other acetate esters, acetaldehyde and furanic compounds with the properties odour and taste were found. Principal component analysis corroborated these results. Monoterpenes were confirmed to be responsible for a typical Muscat aroma, as well as for descriptors such as flowery, rose, citrus and spicy/menthol in distillates made from Muscat varieties. A significant degree of correlation was found between the concentration of C6-alcohols and the frequency of quotation of the descriptor vegetative/grass. Indications were found that vegetative odours of C6-alcohols may act as suppressants of Muscat aroma. A certain degree of congruence was noted between higher concentrations of medium-chain ethyl esters and acetaldehyde, and the occurrence of fruity and nutty odours, respectively. Copyright © 2012 The Institute of Brewing & Distilling