Yellow passion fruit provides a substrate suitable for alcoholic fermentation and holds valuable sensory and nutritional properties that support its use for producing wine. Among the different interesting aspects to consider in the winemaking process, we highlight the analysis of the proteins of the yeast or yeasts responsible for the process; in addition to providing fundamental knowledge about the biotransformations that take place, they can contribute to understanding basic aspects that affect the sensory properties of the wine obtained. This study aimed to analyze the proteomic profile of the yeast Saccharomyces cerevisiae strain E1 (ATCC: MYC-425) during passion fruit fermentation. The process was conducted in a 5 L Sartorius bioreactor with a diluted fruit puree and sucrose, making a medium with a 10% v/v alcohol potential; after 4 days, ethanol reached 8.5% v/v as sugars decreased. Subsequent LC/MS-MS analysis allowed identifying a total of 938 valid proteins: 454 from the fruit substrate and 484 attributed to yeast. Of the latter, 243 proteins were present throughout the fermentation, with GO term analysis highlighting “binding” (78%) and “catalytic activity” (66%) in molecular function, as well as “cellular” (98%) and “metabolic (90%) processes” in biological process domains. These findings may be a significant step forward in understanding the proteomic dynamics of S. cerevisiae in tropical fruit fermentations. By revealing key proteins and their roles in the unique conditions of passion fruit must, this study offers insights for optimizing the wine elaboration procedures and improving organoleptic properties and quality.

Background: Acetification is a complex process driven by acetic acid bacteria (AAB), in which high ethanol and acidity levels require strong microbial metabolic adaptation. Although the microbiota involved in vinegar production has been described, the functional mechanisms that enable these bacteria to maintain metabolic activity remain poorly understood. In this study, the functional dynamics of AAB during Verdejo vinegar acetification were analyzed using a quantitative metaproteomic approach. Methods: Acetification was performed in submerged culture under semi-continuous conditions, and samples were collected at four stages of the cycle (S1–S4). Results: LC-MS/MS analysis led to the identification of 1626 proteins, of which 1409 were assigned to the Acetobacteraceae family. Komagataeibacter europaeus was the dominant species (73.7%). Hierarchical clustering revealed four protein abundance patterns, and differential analysis identified 350 proteins with increased abundance and 169 with decreased abundance, with the greatest changes observed between S1 and S4. Functional annotation and protein–protein interaction analyses indicated that the main metabolic adaptations involve pathways related to energy metabolism, amino acid biosynthesis, membrane-associated functions, cellular homeostasis, and acid stress response. Conclusions: Overall, the results show that K. europaeus concentrates most of the metabolic activity during acetification and that proteome reorganization reflects key molecular strategies for adaptation and survival under high-acidity conditions.