Enhancing the sensory profile of wines by exposing the aromas of the grape variety through the involvement of microorganisms has always been a challenge in winemaking. The aim of our work was to evaluate the impact of different fermentation schemes by using mixed and pure cultures of different Saccharomyces species to Sauvignon blanc wine chemical composition and sensory profile. The Sauvignon blanc must has been inoculated with mixed and pure cultures of S. pastorianus and S. cerevisiae strains. For the mixed fermentation schemes, one strain of S. pastorianus has been inoculated with different proportions of S. cerevisiae (S. pastorianus to S. cerevisiae: 99%–1%, 95%–5%, 90%–10%, 80%–20% and 70%–30% w/w) in co-inoculation with two commercial strains of S. cerevisiae. A total of 13 fermentations trials, three monocultures and 10 mixed cultures were performed in biological triplicate. The fermentation kinetics have been controlled by density measurement and classical oenological analyses were performed based on the International Organisation of Vine and Wine (OIV) analytical methods. The population dynamics were evaluated by the specific interdelta PCR reaction of the Saccharomyces species at the beginning and at the end of the fermentation process. The volatile compounds of the wine aroma, such as the esters, higher alcohols and thiols were analyzed by GC/MS. Sensory assessment by trained panel was carried out for all produced wines. Complete depletion of the sugars was achieved between 10 and 13 days for all the fermentation trials. The population dynamics analysis revealed that the S. cerevisiae strain was the most predominant at the end of the fermentation process in all inoculation ratios that were tested. The wines that were 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 that were fermented only with S. cerevisiae strains. The aroma profile of the produced wines was highly affected by both inoculation ratio and the S. cerevisiae strain that was used. The presence of S. pastorianus strain enhanced the production of the varietal thiols when compared to the samples that were fermented with the S. cerevisiae pure cultures. The mixed inoculation cultures of Saccharomyces species could lead to wines with unique character which can nicely express the varietal character of the grape variety.

Enhancing the sensory profile of wine using different microorganisms has always been a challenge in winemaking. The aim of our work was to evaluate the impact of different fermentation schemes by using mixed and pure cultures of three different Saccharomyces species at classic and cold inoculation temperatures on wine chemical composition and sensory profile. All the produced wines were analysed for the main oenological parameters (total acidity, volatile acidity, residual sugars, alcohol, and malic acid), as well as for volatile aromatic compounds, such as higher alcohols, acetate esters, ethyl esters and varietal thiols. In addition, implantation monitoring at the strain level and sensory analyses were performed in all fermentation trials. The wines fermented with S. pastorianus strains were characterised by significant lower acetic acid production and greater malic acid degradation compared to the wines fermented with S. cerevisiae strains. Interestingly, when the inoculation process for all trials was performed at a cold temperature (13 °C), the typical aromas of Sauvignon blanc were stronger than those in the classic inoculation temperature (18 °C) trials. Furthermore, the co-inoculation of S. pastorianus and S. bayanus resulted in wines exhibiting a higher intensity of citrus fruit notes than the wines fermented with the commercial S. cerevisiae strains. These results show that some strains from different Saccharomyces species other than S. cerevisiae, such as S. pastorianus and S. bayanus, could be promising starters for Sauvignon blanc wines and their performance can be modulated by the inoculation conditions.

The aim of the present study was to assess the effect of the inoculation ratio between Saccharomyces pastorianus strain SP2 and S. bayanus strain BCS103 on the enological properties and aroma profile of Sauvignon Blanc wines. For that purpose, a total of eight different fermentation trials on Sauvignon Blanc must took place. These included spontaneous fermentation as well as inoculation with pure and mixed cultures of the S. pastorianus and S. bayanus strains. The mixed cultures contained different proportions of the two strains (S. pastorianus SP2 to S. bayanus BCS103: 99–1%, 97–3%, 95–5%, 90–10% and 70–30% w/w). Classical oenological analyses were employed to assess the course of fermentation and classical microbiological enumeration combined with inter-delta sequence profile analysis was used for yeast population dynamics estimation. The volatile compounds of each wine were analyzed with GC/MS. The fermentation was completed between 11 and 13 days, while the inoculation ratio significantly affected the chemical composition and the sensorial evaluation of the resulting wines. Based on the sensory evaluation, the least-appreciated Sauvignon Blanc wine was the one resulting from spontaneous fermentation, and the higher the ratio of the S. bayanus strain in the inoculum, the higher the level of appreciation of the wine.

Enhancing flavors and/or improving fermentation parameters through the use of different species of yeast strains is nowadays a frequent challenge in winemaking research, especially for aromatic varieties such as Sauvignon Blanc. In this work, the aim was to focus on the impact of a species not already studied in wine: Saccharomyces pastorianus. Twenty-two fermentations were conducted on a Sauvignon Blanc must by addition of different strains and mixtures of them by using two different inoculation temperatures. The must was inoculated in cold condition with two similar mixtures of S. pastorianus 1 or 2 (70%) and S. bayanus(30%), with S. pastorianus 1 or 2 alone, with the correspondent S. bayanusalone and with two other S. cerevisiae1 and 2 alone as well. For classic condition, the must was inoculated with only one mixture S. pastorianus1 (70%) / S. bayanus(30%), and respectively with S. pastorianus1, S. bayanus and S. cerevisiae 2 alone. Samples were taken all along the fermentations for both conditions in order to check chemical and microbial analyses as well as yeast implantations. The final wines were analysed for alcohol, glucose, fructose, all other classical wine analysis as well as for acetate esters, and higher alcohols. The results underlined that for both S. pastorianus 1 and S. pastorianus 2 strains, the production of acetic acid was zero in cold condition and really low (0.09 g/l) for classic condition regarding S. pastorianus 1. As a consequence, Saccharomyces pastorianus seems to be highly interesting for winemaking, alone or in co-inoculation with S. bayanus.