After 24 hours of treatment with 10% v/v ethanol, the S. cerevisiae strain (UMCC 2592) showed a significant increase in membrane fluidity compared to the untreated control. However, at ethanol concentrations ranging from 14% v/v to 18% v/v, the fluidity values decreased (Fig. 1). This behavior appears to be attributable to an adaptive response of the yeast cells, implemented to reduce the fluidizing impact induced by ethanol.

The rehydration of ADY strains at low temperatures, which are not optimal for yeast, is one of the challenges faced in wineries, both for practical and economic reasons. To address this, two rehydration nutrients were tested to evaluate their effect on the revitalization process of the ADY strain S. cerevisiae UMCC 2592.

The results show that the strain revitalized at 20°C under all conditions exhibits reduced membrane fluidity compared to the same strain cultivated at 25°C for 24 hours. This behavior is consistent with the literature, which attributes membrane stiffening to revitalization at lower temperatures than those optimal for yeast. However, after 24 hours at 25°C, a reduction in membrane rigidity and lower GP values are observed. Notably, the strain revitalized with the nutrient FERMOPLUS Energy Glu 4.0 shows less significant changes in the GP index compared to the other two conditions, suggesting greater efficacy of this nutrient in reducing membrane rigidity at 20°C, and consequently, smaller fluidity fluctuations after 24 hours at 25°C (Fig. 2).