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 induce malolactic fermentation (MLF) after alcoholic fermentation (AF) of must of the Moschofilero cultivar, the only ‘gris’ native grape variety that is cultivated in Greece. For this purpose, Oenococcus oeni strains Viniflora® CH16, Viniflora® Oenos and Viniflora® CiNe were inoculated after the completion of AF driven by the Saccharomyces cerevisiae strain UCLM S325. Growth of the aforementioned starter cultures was assessed during fermentation by classical microbiological techniques, and verification of their dominance was performed by (GTG)5 fingerprinting. Assessment of standard enological parameters and colorimetric analysis were performed by established approaches. Identification and quantification of organic acids, ethanol and glycerol was performed by high performance liquid chromatography (HPLC), while the solid-phase microextraction method (SPME), coupled with gas chromatography/mass spectrometry (GC/MS), was employed for the identification and quantification of volatile compounds. Finally, sensory analysis took place according to ISO 13299:2016. The suitability of the starter cultures employed to drive AF and MLF was exhibited; AF and MLF of the white and rosé wines were completed after 15 days. Upon completion of AF, substantial differences were observed in the chemical characteristics of the white and rosé wines, which were also reflected in the balance descriptor. MLF also resulted in significant changes. In all cases total acidity decreased and volatile acidity and pH value increased, while the vanilla and butter descriptors increased. Interestingly, the color intensity of the rosé wines also increased. A series of strain-dependent changes in the chemical composition and sensory analysis of both white and rosé wines was also observed.

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.

Nemea and Mantinia are famous wine regions in Greece known for two indigenous grape varieties, Agiorgitiko and Moschofilero, which produce high quality PDO wines. In the present study, indigenous Saccharomyces cerevisiae yeast strains were isolated and identified from spontaneous alcoholic fermentation of Agiorgitiko and Moschofilero musts in order to evaluate their oenological potential. Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) recovered the presence of five distinct profiles from a total of 430 yeast isolates. The five obtained strains were evaluated at microvinifications trials and tested for basic oenological and biochemical parameters including sulphur dioxide and ethanol tolerance as well as H2S production in sterile grape must. The selected autochthonous yeast strains named, Soi2 (Agiorgitiko wine) and L2M (Moschofilero wine), were evaluated also in industrial (4000L) fermentations to assess their sensorial and oenological characteristics. The volatile compounds of the produced wines were determined by GC-FID. Our results demonstrated the feasibility of using Soi2 and L2M strains in industrial fermentations for Agiorgitiko and Moschofilero grape musts, respectively.