Effects of film-forming Pichia and Candida yeasts on cider and wine as post-fermentation contaminants.

This study investigates the growth capacity of film-forming yeasts from the genera Pichia and Candida in cider and wine, and their effects on the chemical composition and aroma profiles of these alcoholic beverages. Results show that species such as Candida californica, Pichia fermentans, and Pichia kluyveri grow primarily in low-alcohol cider, while Pichia membranifaciens, Pichia manshurica, and Pichia kudriavzevii can survive and proliferate in wines with higher ethanol content, up to 13.18% (v/v). Yeast contamination significantly alters concentrations of odour-active compounds—including esters, fatty acids, alcohols, aldehydes, ketones, terpenes, and lactones—affecting the sensory characteristics of cider and wine in a strain- and beverage-specific manner. The study highlights ethanol content as a key factor limiting yeast growth and underscores the need for further research on the metabolic mechanisms of film formation and the sensory impact of these yeasts in fermented beverages.