Influence of native coffee yeast fermentation on phenolic content, organic acids, and volatile compounds in cascara

Fermentation has been shown to significantly influence the quality of cascara, a functional beverage derived from dried coffee cherry pulp. While native coffee yeasts are acknowledged for their role in modulating the sensory characteristics of coffee, their impact on the quality of cascara has not been systematically investigated. This study successfully isolated 12 aromatic yeast strains from wet coffee fermentation and evaluated their potential as starter cultures for cascara fermentation. The results revealed that a mixed culture of Wickerhamomyces anomalus YN5 and Kazachstania humilis YN9 significantly enhanced the phenolic content and antioxidant activity of cascara by 12.68% and 10.77%, respectively, compared to those of unfermented cascara. Furthermore, cascara fermented with this mixed yeast culture exhibited markedly increased levels of acetic acid, lactic acid, ethanol, linalool, benzyl alcohol, and acetophenone, thereby augmenting its acidity, alcoholic notes, and floral-fruity aroma. These findings suggest that native coffee yeasts can serve as effective starter cultures for improving both the sensory and nutritional quality of cascara beverages. • The influence of native coffee yeast fermentation on cascara characteristics was studied. • Selected yeast fermentation could enhance the phenolic content and antioxidant activity of cascara. • Fermented cascara contained higher levels of alcohols, organic acids, ketones, and esters. • Native coffee yeasts can serve as effective starter cultures for cascara fermentation.