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Degradation of Monastrell grape skins: effect of individual enzymatic activities and their synergic combination

Apolinar-Valiente, Rafael, Romero-Cascales, Inmaculada, Gómez-Plaza, Encarna, Ros-García, José María
European food research & technology 2017 v.243 no.11 pp. 1933-1942
cell wall components, cell walls, color, endo-1,4-beta-glucanase, enzyme activity, food research, grapes, maceration, pH, pectinesterase, polygalacturonase, ripening, synergism, tartaric acid, winemaking
The diffusion of valuable components, from the grape skin into the must is limited by a barrier formed by the cell walls. The deconstruction of the cell wall matrix during fruit ripening probably involves the synergistic action of different enzymatic activities. A degradation of cell wall from grape skin during winemaking by addition of several different enzymatic activities could be deduced. However, the action of the maceration enzymes seems contradictory. This work studies the effectiveness of the addition of three purified enzymatic activities on skin cell wall degradation from Monastrell grapes, considering the possible influence of the cell wall composition and morphology, as well as the potential enzymatic synergy. A synthetic solution (5 g/L tartaric acid; pH value 3.6) with Monastrell grape skins was supplemented with polygalacturonase, cellulase and pectin methylesterase enzymatic activities, together with its paired combinations, and compared to a control sample. Oligouronides, color intensity and total phenolic index (TPI) from the synthetic solution were measured at 12, 24, 36, 60, 84 and 120 h for all the experiences. Cellulase activity acts sooner in Monastrell grapes skin, compared to polygalacturonase enzymatic activity. Concerning combined treatments, all enzymatic combinations show more or less a synergy. This synergistic effect is higher when polygalacturonase + cellulase enzymatic combination is added, increasing oligouronides amount, color intensity and TPI between 12 and 84 h. The other two combinations show an increase for TPI and color intensity only at 24 h. Polygalacturonase + pectin methylesterase combination presents higher oligouronides content only at 36 h.