Cascara Kombucha: The Role of Fermentation and Particle Size in Enhancing Antioxidant and Bioactive Properties

This study aims to evaluate the effects of different cascara particle sizes and variations in the kombucha fermentation process on the bioactive compounds and antioxidant properties of cascara (<i>Coffea arabica</i> L.) kombucha. Cascara tea (CT), cascara tea with sugar (CS), and cascara kombucha (CK) were prepared using whole, coarsely ground, and finely ground cascara. A finer particle size enhanced color intensity and improved the extraction of bioactive compounds. CK prepared with finely ground cascara demonstrated the highest total phenolic content (TPC), total flavonoid content (TFC), and ferric reducing antioxidant power (FRAP). Fermentation influenced the profile of phenolic acids, leading to a decline in most compounds, except for vanillic acid in all CK samples, which increased during fermentation. Interestingly, apigenin levels increased, while quercetin levels decreased throughout fermentation. These findings highlight the role of fermentation, sugar addition, and particle size reduction in enhancing phenolic extraction and antioxidant potential in cascara-based beverages, particularly cascara kombucha.