Evaluation of Indigenous Candida oleophila and Candida boidinii in Monoculture and Sequential Fermentations: Impact on Ethanol Reduction and Chemical Profile in Chilean Sauvignon Blanc Wines

Abstract

The study of non-Saccharomyces yeasts in wine fermentations allows the exploration of new alternatives for the reduction of ethanol in wines. The objective of this work was to evaluate the fermentation capacity of two indigenous Candida yeasts (C. oleophila and C. boidinii) in monoculture and sequential fermentations (laboratory and microvinification scale) to produce Chilean Sauvignon Blanc wine. Fermentations were monitored by the determination of ethanol, glycerol, organic acids, and residual sugars. The results indicated that at the laboratory scale for both the monoculture and sequential fermentations it was possible to reduce the ethanol concentration on 0.77% v/v (monoculture) and 1.5% v/v (sequential) for C. oleophila and 0.50% v/v (monoculture) and 0.04% v/v (sequential) for C. boidinii compared to S. cerevisiae (12.87% v/v). Higher glycerol concentrations were produced in monoculture than sequential fermentations (C. oleophila: 9.47 g/L and C. boidinii 10.97 g/L). For microvinifications, the monoculture and sequential fermentations with C. boidinii managed to reduce ethanol content by 0.17% v/v and 0.54% v/v, respectively, over the S. cerevisiae control (13.74% v/v). In the case of C. oleophila, the reduction was only observed in sequential fermentations with 0.62% v/v. Interestingly, grapes with higher sugar concentration resulted in wines with lees ethanol concentrations. This might be associated to the use of C. oleophila (13.12% v/v) and C. boidinii (13.20% v/v) in sequential fermentations microvinification scale.

Evaluation of the Bio-Protective Effect of Native Candida Yeasts on Sauvignon Blanc Wines

“…Non-Saccharomyces yeasts, particularly Candida oleophila and Candida boidinii, have gained little attention in enological research, unlike other commercial strains including Torulaspora delbrueckii, Metschnikowia pulcherrima, and Lachancea Thermotolerans [16][17][18][19][20][21][22][23][24]. Actually, only one study reported on the fermentative potential of C. oleophila and C. boidinii and their capacity to reduce ethanol during Sauvignon Blanc wine production [33]. However, its antimicrobial qualities have not yet been studied in wine fermentation, despite the potential demonstrated in other food production areas.…”

“…However, this may be due to the aforementioned lack of control over LAB (Table 2), given that the presence of hetero-fermentative LAB can increase CO 2 and ethanol concentrations in wine [40]. The rapid fermentation caused by C. boidinii yeast compared with C. oleophila had already been reported in the literature [33], where sequential fermentation with the yeasts C. boidinii-S. cerevisiae finished fermentation by day 8, while the C. oleophila-S. cerevisiae duo finished by day 15. The importance of this lies in the fact that ethanol is considered an active bio-controlling compound [15] since most microorganisms are inhibited by high concentrations of this compound.…”

“…In fact, the Candida boidinii 1 × 10 7 strategy presented an ethanol production of 12.78 ± 0.15 % v/v (Table 4), a significantly higher concentration than that obtained by the sulfites control and the other strategies. This behavior was unexpected since the literature reports that non-saccharomyces yeasts in general, and Candida boidinii in particular, are yeasts that can reduce ethanol levels in wine [33,39]. However, this may be due to the aforementioned lack of control over LAB (Table 2), given that the presence of hetero-fermentative LAB can increase CO 2 and ethanol concentrations in wine [40].…”

“…The yeast Candida boidinii has also shown antimicrobial potential for table olive production, cutting undesirable bacteria from oil, and granting sensory advantages to the final product [32]. There is currently only one study about these yeasts in winemaking, concerning their fermentation potential and capacity to reduce ethanol in wine [33].…”