Report for the scientific sojourn at the Université de Bourgogne, France, from July until October 2007..Surlie ageing after second fermentation is a fundamental operation in the production of quality sparkling wine like Cava and Champagne. Recently, the importance of the interaction between wine and lees cell surface has been reported. Cell surface properties depending on wall biochemical composition are major determinants in microbial interactions, having important repercussions in several technological aspects. Sorption and flocculation are especially important in sparkling wine production, and are governed by distinct cell surface properties. The aim of the present research carried out during the four months of the stage was to know the implication of lees surface modifications occurring during surlie ageing in sparkling wine quality and elaboration. The relationship between physico-chemical properties such as hydrophobicity, charge and electron-donor characteristics, and the yeast surface sorption capacities, we determined these factors in a model system. Then, real industrial lees samples were investigated. The surface properties of sparkling wine lees from the same strain of Saccharomyces cerevisiae were characterized according to the time of surlie ageing, and their possible influence on lees sorption and flocculation capacity was evaluated. Surlie ageing after second fermentation is a fundamental operation in the production of quality sparkling wine like Cava and Champagne. Recently, the importance of the interaction between wine and lees cell surface has been reported. Cell surface properties depending on wall biochemical composition are major determinants in microbial interactions, having important repercussions in several technological aspects. Sorption and flocculation are especially important in sparkling wine production, and are governed by distinct cell surface properties. The aim of the present research carried out during the four months of the stage was to know the implication of lees surface modifications occurring during surlie ageing in sparkling wine quality and elaboration. The relationship between physico-chemical properties such as hydrophobicity, charge and electron-donor characteristics, and the yeast surface sorption capacities, we determined these factors in a model system. Then, real industrial lees samples were investigated. The surface properties of sparkling wine lees from the same strain of Saccharomyces cerevisiae were characterized according to the time of surlie ageing, and their possible influence on lees sorption and flocculation capacity was evaluated.

Proyecto de investigación realizado a partir de una estancia en la Université de Bourgogne entre julio y octubre del 2007. La crianza “surlie” tras lasegunda fermentación es una operación fundamental en la producción de vinos espumosos como Cava y Champagne. Recientemente se ha demostrado la importancia de la interacción entre el vino y la superficie de las lías. Las propiedades superficiales de las células, que dependen de su composición bioquímica, son factores determinantes en las interacciones microbianas, con importantes repercusiones en varios aspectos tecnológicos. La adsorción y la floculación son especialmente importantes en la producción de vinos espumosos y se rigen por distintas propiedades superficiales de las células. El objetivo de la investigación realizada durante los cuatro meses de la estancia, fué conocer la implicación de las modificaciones producidas en la superficie de las lías durante la crianza “surlie” en la calidad y elaboración de vinos espumosos. Se ha determinado en un sistema modelo la relación entre capacidad de adsorción y propiedades fisicoquímicas superficiales tales como hidrofobicidad, carga y características de acido/bas de Lewis. Seguidamente, se investigaron muestras reales de líasde vino espumoso.Sus propiedades superficiales se caracterizaron en función del tiempo de crianza, y se evaluó su influencia sobre adsorción y floculación. Las propiedades de superficiales de las células resultaron correlacionadas con su capacidad de adsorción en sistema modelo, en particular las propiedades ácido/base de Lewis y el potencial Z. Las propiedades superficiales de muestras reales de lías, esultaron dependientes del tiempo de crianza “surlie”. La liberación de manoproteinas de la pared celular durante la autolisis explicaría la disminución de la hidrofobicitdad y el aumento del potencial de Z y del carácter aceptor de electrones observados. La mayoría de las propiedades superficiales de las lías resultaron intercorrelacionadas, pero el stepwise multiple regression analysis indica que sólo la hidrofobicidad y las características de ácido/base de Lewis de la superficie de las lías influyen en la floculación y capacidad de adsorción, que disminuyó a lo largo del la crianza.