FERMENTACIONES MALOLÁCTICAS EN VINIFICACIONES EN TINTO DE LA NORPATAGONIA ARGENTINA Y SU RELACIÓN CON EL SUSTRATO

CARREÑO, VIVIANA A.; DEL MÓNACO SILVANA M.; SEMORILE, LILIANA C.; CABALLERO, A. C.

Córdoba

Congreso; IV Congreso Internacional de Ciencia y Tecnología de los Alimentos Córdoba 2012; 2012

Ministerio de Ciencia y Tecnología de la Provincia de Córdoba

Alcoholic and malolactic fermentations are the main processes that take place in winemaking. The malolactic fermentation (MLF), i.e. the conversion of L-malic to L-lactic acid and carbon dioxide, is the biochemical process by which lactic acid bacteria (LAB) contribute to the wine deacidification. Today, the MLF is a widespread practice in red wine elaboration in all winegrowing regions of the world because it improves the biological stability and sensorial properties of the wine enhancing its flavour and complexity. In Comahue region (Argentinean North Patagonia) MLF is spontaneously carried out by wild LAB biota associated with the must/wine and multiple factors, which can be grouped into viticultural and oenological practices, could affect its evolution. The aim of this work was to characterize the influence of substrate quality on evolution of spontaneous MLF associated with regional red winemaking. Twenty six regional grape musts from Vitis Vinifera L. c.v. Pinot noir (11), Merlot (6), Malbec (5), Cabernet Franc (2) and Petit Verdot (2) were winemaking at industrial scale at the very least during two vintages. Alcoholic fermentations (AF) were carried out by grape inoculation with a commercial starter and MLFs were carried out spontaneously. MLF was monitored following the L-malic and L- lactic acids evolution by enzymatic methods. All enological parameters of wines were determined according to the methods proposed by Instituto Nacional de Vitivinicultura (INV). FMLs associated with Malbec, Cabernet franc and Petit verdot vinifications were all successful but they show a high failure percentage in Merlot (33%) and Pinot noir (54%) wines. The FML successful or failure percentage was closely related to wine pH, an enological parameter significantly affected by grape variety and, within this, by the source vineyard and vintage year. The MLF control by select indigenous BAL strains would be advisable in order to improve qualities of wines preserving the own natural biodiversity of the region.