Comparison of the influence of Saccharomyces pastorianus to Saccharomyces cerevisiae and Saccharomyces bayanus inoculation ratio to oenological characteristics of Sauvignon Blanc wine

Abstract

The aim of our work was to evaluate the impact of different fermentation schemes by using mixed and pure cultures of S. pastorianus and S. cerevisiae or S. bayanus. For the mixed fermentation schemes, one strain of S. pastorianus has been inoculated under different proportions (99%/1%, 97%/3%, 95%/5%, 90%/10% and 70%/30% w/w) in co-inoculation with two commercial strains of S. cerevisiae and one commercial Saccharomyces bayanus strain. The fermentation kinetics has been controlled by density measurement and classical oenological analyses were performed based on OIV analytical methods. The population dynamics was evaluated by the specific interdelta PCR reaction of the Saccharomyces species in the beginning and in the end of the fermentation process. Volatile compounds of the wine aroma, such as esters, higher alcohols and thiols were analyzed by GC/MS. Sensory assessment by trained panel was carried out for all wines. The wines fermented with S. pastorianus, either in pure or mixed cultures, were characterized by significantly lower acetic acid production and higher malic acid degradation when compared to the wines fermented with S. cerevisiae strains. The presence of S. pastorianus strain enhanced the production of the varietal thiols when compared to the samples fermented with the S. cerevisiae pure cultures. The wines produced by the S. bayanus or cerevisiae monocultures and the ones produced by the co-culture with S. pastorianus at 70%-30% ratio (S. pastorianus to S. bayanus or cerevisiae) were overall better rated from a sensory point of view.