Relationships Between Storage Conditions of Grape Pomace and Volatile Composition of Spirits Obtained Therefrom

Abstract

This study reports on the effects of addition of tartaric acid, addition of pectinase, time of anaerobic storage, and the storage container material on the concentrations of volatiles in marc distillates of Alvarinho and Loureiro varieties. The aim of this work is to predict how the concentration of every major volatile responds to each manipulated processing factor in each of three distillate cuts, a condition necessary to rationalize the process of the manufacture of bagaceiras. Fusel alcohols were, quantitatively, the largest group of flavor compounds in all cases, ranging from 395 to 2029 mg/L. Ethyl acetate and ethyl lactate were the most concentrated esters, ranging from 176 to 9614 and from 0 to 310 mg/L, respectively. Fermentation time is the manipulated variable that most strongly affected composition of marcs in terms of higher alcohols, while addition of pectinases and material of container are the manipulated variables that most strongly affected composition in terms of methanol (with a concentration range of 2694 - 6960 mg/L) and 2-butanol (with a concentration range of 0 - 279 mg/L). The effect of pectinase addition is statistically the most significant for the methanol content, whereas the effect of fermentation time is statistically the most significant for the 2-butanol content.