Biotechnological potential of Non-Saccharomyces yeasts to modulate flavor profiles in specialty coffee fermentation.

Yeast inoculation in coffee during Self-Induced Anaerobic Fermentation (SIAF) has attracted attention for exploring the fermentative potential of both starter cultures and native microbiota. While Saccharomyces cerevisiae and Torulaspora delbrueckii yeasts have been extensively studied, the role of the other non-Saccharomyces yeasts in coffee fermentation remains underexplored. This study evaluated the fermentative performance of five non-Saccharomyces yeasts (Pichia kluyveri CCMA0237, Hanseniaspora uvarum CCMA0236, Wickerhamomyces anomalus CCMA1640, Meyerozyma caribbica CCMA1738, and Candida parapsilosis CCMA0544) using the SIAF method. Yeast population dynamics, organic acid composition, volatile profiles, and sensory attributes were analyzed to compare the metabolic contributions of each strain. Across all fermentations, H. uvarum was the only yeast showing a population increase by the end of the process, whereas M. caribbica presented the lowest final counts (2.601 log CFU/g in inoculated and 1.389 log CFU/g in spontaneous fermentation). Lactic acid was the predominant organic acid, with the highest concentration detected in C. parapsilosis CCMA0544 fermentation (8.58 g/kg). Heneicosane and hexadecane were exclusively detected in C. parapsilosis CCMA0544 fermentations. W. anomalus fermentations were characterized by high levels of pyridine derivatives, particularly 5-methylpyridin-2-amine. Among the inoculated strains, the fermentation with M. caribbica CCMA1738 achieved the highest sensory score, followed by P. kluyveri CCMA0237, demonstrating their strong biotechnological potential to modulate coffee fermentation and generate specialty products with distinct sensory profiles.