Aroma enhancement in fig wine through sequential fermentation with Candida humilis and Torulaspora delbrueckii: A...

Three yeast strains isolated from fig fruits (Candida humilis DBXD1, Torulaspora delbrueckii S14, and Saccharomyces cerevisiae S2-7) were evaluated for their potential to enhance the aromatic complexity of fig wines. Enzyme activity assays demonstrated that C. humilis DBXD1 exhibited maximum β-glucosidase activity (2.94 ± 0.13 U/mg prot) and T. delbrueckii S14 showed the highest esterase activity (0.94 ± 0.06 U/mg prot). Sequential inoculation of these non-Saccharomyces strains with S. cerevisiae S2-7 increased contents of key aroma compounds in fig wines, including ethyl acetate, isoamyl acetate, hexyl acetate, butanoic acid esters, isoamyl alcohol, nonanal, 2-nonanone, and α-terpineol. Metabolic pathway analysis identified valine, leucine and isoleucine degradation, glycine and serine metabolism, and the glucose-alanine cycle as the primary differential pathways contributing to flavor enhancement. These findings demonstrated that sequential inoculation with indigenous high enzyme-producing yeasts provides a practical foundation for industrial production of fig wines with distinctive aromatic characteristics.