Impact of drying technologies on polyphenols and antioxidant capacity in chokeberry pomace tea infusion

This study evaluated the effects of microwave vacuum drying (MVD), atmospheric drying (AD), and freeze-drying (FD) on polyphenols, antioxidant capacities, and colour of chokeberry pomace tea infusions, which were combined with market tea in various ratios for flavour enhancement: 100–0%, 50–50%, and 60–40%. 3.5 g sample was infused in 200 mL of boiled water for 5 min, and tested for total phenolic content (TPC), total anthocyanins (TA), antioxidant capacity (FRAP, TEAC, and DPPH), and colour change. Results showed significantly higher TPC and TA in the 100% samples than in the mixed samples. The FD and MVD (100%) samples had the highest TPC and TA, respectively. Antioxidant capacities (DPPH and TEAC) did not differ significantly between 100% pomace and the mixed samples. The study concludes that MVD and FD drying technologies effectively preserved high polyphenol content and colour for the tea infusion; and other fruits can enhance the flavour of the tea.