Effect of microwave maceration and SO₂ free vinification on volatile composition of red wines

Abstract

This study evaluates the effect of microwave treatment in grape maceration on the content of free and glycosidically bound varietal compounds) of must and wine and on the overall aroma of wines produced in the presence and absence of SO2. The volatile compounds were isolated by solid phase extraction and analyzed by gas chromatography-mass spectrometry, carrying out a sensory evaluation of wines by quantitative descriptive analysis. Microwave treatment significantly increased the free and bound fraction of most varietal compounds must. Wines from microwave maceration showed faster fer-mentation kinetics and shorter lag phase, resulting in an increase in some volatile compounds of sensory relevance. The absence of SO2 resulted in a decrease in concen-tration of some volatile compounds, mainly fatty acids and esters. The sensory assessment of wines from microwave treatment was higher than the control wine, especially in wines without SO2, which had higher scores in the “red berry” and “floral” attributes and more intensity of aroma. This indicates that treatment with MW in maceration can be very positive to increase the aroma of wines reducing the presence of SO2.