Impact of novel biotechnological strategies in the fermentation of Sicilian wines on the content of total polyphenols

Catarratto is the main white grape variety in Sicily, and enhancing its value is a key goal. This study investigated how different fermentation strategies affect the total phenolic content (TPC) in wines made from Catarratto grapes under different winemaking protocols. Three biotechnological approaches were explored: (i) sequential inoculation using three non-Saccharomyces yeast strains (Starmerella lactis-condensi, Candida oleophila, and Lachancea thermotolerans) followed by Saccharomyces cerevisiae; (ii) Catarratto wines that are non-macerated or subjected to short- or long-term maceration with seeds and peel, with/without sulfites, and fermented using St. lactis-condensi, S. cerevisiae, and lactic-acid bacteria; and (iii) traditional sparkling wines with S. cerevisiae strains. TPC was measured using the Folin–Ciocalteu method. Fermentation generally led to a reduction in TPC compared to must. In approach (i), the highest and lowest TPC values were observed in wines fermented only with S. cerevisiae and in those pre-fermented with St. lactis-condensi and L. thermotolerans, followed by S. cerevisiae, respectively. In approach (ii), maceration increased TPC, particularly when St. lactis-condensi was followed by S. cerevisiae. In sparkling wines (iii), TPC varied significantly depending on the selected non-commercial S. cerevisiae strain. These results suggest that tailored fermentation strategies can enhance the phenolic content and quality of Catarratto-based wines.