Effect of microbial surfactants on pectinase activities during the winemaking process

MARTÍN, M.C.; MERÍN, M.G.; CABEZA, M.S.; SABATÉ, D.C.; AUDISIO, M.C.; MORATA DE AMBROSINI V.I.; CASTRO, G.R.

Trivandrum, India

Conferencia; International Conference on New Horizons in Biotechnology (NHBT); 2007

Pectinases are multi-enzymatic complexes highly effective in polygalacturonic depolymerization. In order to retain aroma and flavour compounds the winemaking process is conducted at low temperatures. However, extraction of polyphenolic compounds, which are responsible of wine colour and antioxidant properties from grapes, is not favoured at low temperatures. Besides, during the grape maceration process, hydrophobic molecules cover the grape berries surface. Therefore, a degradative enzyme able to enhance the extraction procedure is a must. In a previous work, a surfactant- producer wild-type microorganism was isolated and identified as Bacillus subtilis. On the other hand, enzyme production active at low temperature have been optimized. In the present study the effect of surfactant on pectinase activity during the winemaking process of Malbec wine variety was reported. We found that the surfactant did not enhance the enzymatic hydrolysis of pectin in the grape suspension. However, extraction of pigments and polyphenolic molecules was increased by the presence of surfactant on exhausted grape skins compare to control without surfactant. Our results showed that the combination by pectinases with surfactants at low concentration are beneficial for winemaking of Malbec, because of the reduction of viscosity and enhanced extraction of pigments and polyphenols.