Influence of hot air drying on phenolic compounds and antioxidant capacity of blueberry (Vaccinium myrtillus) fruit and leaf

The present study was undertaken to assess the effects of hot air drying on phenolic compositions, total phenolic (TP) content, total anthocyanin (TA) content, as well as antioxidant capacities of methanol extracts from blueberry (Vaccinium myrtillus) fruit and leaf introduced in Kapıdağ region of Turkey climate conditions. A total of twenty-two phenolic standards were screened by HPLC, total phenols were measured by spectrophotometric methods, antioxidant capacity was determined using DPPH, CUPRAC, ABTS, and FRAP assays in the blueberry fruit and leaf extracts. Analysis by HPLC revealed that fruit extracts have different phenolic profiles due to drying process and contain syringic acid, myricetin, naringin, (-)-epicatechin, and malvidine-3-O-glucoside chloride as the main compounds. Leaf extracts had higher resveratrol concentrations than fruit extracts. The TP and TA contents gradually increased when the blueberry fruits were dried under hot air condition. The fresh and dried blueberry fruit and leaf extracts showed similar antioxidant capacity values. Significant relationships between antioxidant capacity and TP were found.