Effect of microbial surfactant on pectinase activity during the winemaking process.

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

Trivandrum

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

The Biotech Research Society (BRSI) AND National Institute for Interdisciplinary Science and Technology (NIIST)

Pectinases are highly effective multicomponent enzymatic preparations in vegetable pectin depolymerization with a several degree of esterification. In winemaking, three are the stages in which pectic enzymes can be added: at the first stage, while grapes are being crushed; at the second stage, in treatment of crushed grapes to improve yield and extraction; and finally in clarification and filtration. Winemaking conducted at low temperatures is important to retain aroma and flavour compounds; however this is against of the polyphenolic substances extraction, responsible of colour and antioxidant properties of wine. These opposite phenomenons justify the use of enzymes able to enhance the extractive effect. On the other hand, in extraction or maceration process, the molecules which are part of the berry grape surface generate a certain (some) hydrophobicity in the zone of contact solid-liquid. In the same way of other vegetable tissues, hydrophobic components are located in the cuticle of primary cell wall, where pectin acts like join material. Access to pectin molecules will be seen facilitated for the presence of surfactants; this is substances that reduce surface tension. Within of different alternatives in the use of surfactants are the microbial origin ones. In previous works, in our investigation equipments, has been got (achieve) to produce and purify a surfactant obtained for an isolation of Bacillus, which was opportunely classified like subtilis. On the other hand, in our works have been developed enzymatic preparations, which are active at low temperature. With purpose of enhance lytic action of these pectinases, in the present study, the use concomitant of surfactants and pectinases is assayed. Assays consisted in analysing on the one hand effect of surfactants on lytic action of a pectin suspension, and on the other, the role coadjuvant of surfactants on pigments and polyphenolic compounds of wine was analysed in the extraction on exhausted grape skins of Malbec variety. Surfactants did not collaborate on hydrolysis of a pectin suspension, which is logical due to there the access to substrate is direct and hydrophobicity zones would be not generated. It was observed the effective collaboration of surfactants in pigments and polyphenolic substances extraction on exhausted grape skins in very small aliquots with respect to enzyme sample. These results have allowed concluding that the extractive effect of pectinasas can be enhanced by the use of microbial surfactants.