Impact of Torulaspora delbrueckii During Fermentation on Aromatic Profile of Vidal Blanc Icewine

Abstract

Non-Saccharomyces yeasts usually have a positive effect on improving the diversity of wine aroma and increasing the differentiation of wine products. Among these non-Saccharomyces yeast species, Torulaspora delbrueckii is often studied and used in winemaking in recent years, but its application in icewine has not been reported yet. In this study, indigenous T. delbrueckii strains (TD1 and TD2) and Saccharomyces cerevisiae strains (commercial yeast SC1 and indigenous icewine yeast SC2) were sequentially inoculated for icewine fermentations; meanwhile, pure S. cerevisiae (SC1 and SC2) fermentations were used as the control; TD1, TD2, and SC2 strains used were screened from spontaneous fermentations of Vidal blanc icewine. The aim was to investigate the effect of T. delbrueckii on the aroma complexity of icewine, which is of great significance to the application of T. delbrueckii in icewine production. The results showed that T. delbrueckii was completely replaced by S. cerevisiae at the middle and later fermentative stages in mixed culture fermentations. Compared with the icewine fermented with pure S. cerevisiae, mixed culture fermented icewines contained lower acetic acid and ethanol, and higher glycerol. The inoculation of T. delbrueckii greatly impacted the levels of several important volatile compounds, and more 2-phenylethyl alcohol, isoamyl acetate, linalool, D-limonene, p-cymene and cineole were produced, and the fruity, flowery, and sweet characteristic was intensified. Moreover, the relevance of strain-specificity within T. delbrueckii to aroma compound differences was shown. To our knowledge, this study is the first to investigate the application of T. delbrueckii in Vidal blanc icewine fermentation, and volatile aroma compounds in the icewine fermented by T. delbrueckii and S. cerevisiae.

Impact of Candida railenensis during fermentation on the aromatic profile of Vidal blanc icewine

“…Many studies have shown that non- Saccharomyces yeasts (such as C. zemplinina ) have the effect of reducing ethanol content in wine fermentation (Giaramida et al, 2013 ; Contreras et al, 2014 ; Englezos et al, 2019 ). In recent years, consumers have become more interested in wines with lower ethanol concentrations for health and taste reasons (Ballester-Tomás et al, 2017 ; Li et al, 2022 ), and higher ethanol concentration has an undesired effect of reducing the complexity of wine sensory properties (Contreras et al, 2014 ). In terms of glycerol, higher glycerol content in the mixed culture fermented icewines suggested that C. railenensis could increase glycerol yield; therefore, the smoothness and viscosity of icewine structure/body perception of mixed culture fermentation should be stronger than those of the control fermentation (Swiegers et al, 2005 ), and the sensory analysis confirmed this fact.…”

Chemometric Differentiation of White Wines from a Low-Aromatic Grape Obtained by Spontaneous Fermentation, Enriched with Non-Saccharomyces, or with a High-Glutathione-Producing Saccharomyces Yeast

“…This conversion can be catalyzed by enzymes during wine fermentation or in the presence of low pH values [39]. It provides a citrus and fresh orange aroma to the wine [40]. Lastly, among the miscellaneous compounds, the presence of 2,4-di-tert-butylphenol and 3,5-di-tert-butyl-4hidroxybenzaldehyde stands out, which were produced by S. cerevisiae and was present in all wines.…”