Combined Use of Pectolytic Enzymes and Ultrasounds for Improving the Extraction of Phenolic Compounds During Vinification

Abstract

Phenolic compounds provide important quality attributes to red wines. These compounds are found inside the vacuoles of the plant cells of the skin and seeds of the grape. During maceration, they diffuse to the must/wine, although for this to happen, the vegetal cell walls need to rupture. Pectolytic enzymes and high-power ultrasound (US) may facilitate this objective. Therefore, this study analyzes the extraction efficiency of phenolic compounds using pectolytic enzymes and US (applied at 2 different times of the maceration period) alone and in combination. The chromatic characteristics of the wines were analyzed by spectrophotometry and chromatography at the end of the alcoholic fermentation and after 3 months in bottle. The treatment with enzymes alone increased the concentration of tannins by 13%, but US increased both the extraction of anthocyanins and tannins (7 and 16% respectively). The combination of enzymes and US, both applied at the beginning of the maceration time, did not improve the results of the treatments separately. However, when the enzyme was allowed to act alone during the first days of maceration before US was applied, a statistically significant synergistic effect was observed, increasing the color intensity by 18% and total phenol content by 21%, and especially marked was the effect on tannin extraction, whose concentration increased in the wines by 30% at the end of alcoholic fermentation.