The impact of carbohydrate-active enzymes on mediating cell wall polysaccharide-tannin interactions in a wine-like matrix

Abstract

Tannins are present in grape skins and seeds from where they are transferred into the must-wine matrix during the maceration stages of winemaking. However, tannin transfer is often incomplete. This could be due, among other reasons, to tannins becoming bound to grape cell wall polysaccharides, including soluble polymers, which are released during vinification and are present in high concentrations in the must/wine. The use of cell wall deconstructing enzymes offers the possibility of reducing these interactions, releasing more tannins into the final wine. The main aim of this study was to evaluate the optimal addition (individually, in combination or sequentially) of hydrolytic enzymes that would prevent tight polysaccharide-tannin associations. The use of comprehensive microarray polymer profiling (CoMPP) methodology provided key insights into how the enzyme treatments impacted the grape cell wall matrix and tannin binding. The results demonstrated that polygalacturonase + pectin-lyase promoted the highest release of tannins into solution.

Keywords: Cell wall; Cellulase; Pectin lyase; Polygalacturonase; Polysaccharides; Tannins; Wine.