The contribution of Saccharomyces cerevisiae strains to the aromatic profile of wines from the vinhos verdes region

Abstract

Sensory characteristics and flavour compounds of wines are significantly determined by the diversity and composition of the fermentative yeast population. Consequently, there has been an increasing demand for autochthonous wine yeasts to be used as fermentation starters. The objectives of the present study were to assess the intra-strain variability of Saccharomyces cerevisiae strains and to evaluate their application as starter cultures for the production of balanced wines that reflect characteristic aroma and flavour determinants of wines from Vinhos Verdes Region in Portugal. From the S. cerevisiae culture collection of the Minho University, a set of 47 genetically most distinct strains (based on microsatellite data) was chosen by means of neural networks. Must of the grape variety “Trajadura”, prepared during the 2006 harvest season, was inoculated with the selected strains and their implantation/predominance during small-scale fermentation (500 ml) was monitored by mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP). Trials in larger scale (50 l) were conducted with the 5 best performing strains. Aromatic profiles (monoterpenes, esters, C6-alcohols, higher alcohols, volatile fatty acids) of final wines were evaluated by GC-FID and GC-MS. The presented approach shows relationships between aromatic profiles and the implantation of specific strains or groups of strains, capable to ensure a balanced wine flavour and maintaining characteristic aroma and flavour determinants of wines from the Vinhos Verdes Region.