Influence of addition of insoluble solids, different yeast strains and pectinesterase enzyme on the quality of apple wine

Abstract

Rate of fermentation and physico-chemical characteristics of apple wines, owing to the addition of different yeast strains, insoluble solids and pectinesterase enzyme, were examined. The highest rates of fermentation and ethanol production were found in the wine fermented by yeast strain UCD 505, while strain UCD 595 gave the smallest amount of methanol. The addition of insoluble solids to the apple juice significantly increased the levels of methanol, vitamin C, amyl alcohol, total volatiles, rate of fermentation, tannins, colour units, Mn and Zn. Addition of insoluble solids decreased pH, titrable acidity, ethanol, total sugars, total esters, and K, Mg, Ca, Cu and Fe content of the wine. Addition of pectinesterase enzyme significantly increased all the parameters examined except for pH, vitamin C, total esters, Mn and Mg content. Application of cluster analysis to the results of rate of fermentation, reducing sugars, volatile acidity and ethanol showed that the influence of the yeast strains was more than the influence of insoluble solids or pectinesterase enzyme addition. Consideration of more parameters showed that there was a clear interaction between the yeast strain, insoluble solids and the pectinesterase enzyme. Addition of insoluble solids to the must led to the production of some undesirable quality characteristics. In contrast, specific yeast strains and enzyme addition improved various physico-chemical characteristics of the wine. Pre-settled or clarified juice was preferred to produce a quality apple wine. Copyright © 2013 The Institute of Brewing & Distilling