Changes in bioactive compounds and antioxidant activity during convective drying of murta (Ugni molinae T.) berries

Murta (Ugni molinae T.) berries were air-dried at five temperatures (40, 50, 60, 70 and 80 degrees C), and the changes in -carotene, phenolic acids, total phenolic and flavonoid contents and antioxidant capacities (DPPH and ORAC) were investigated. The berries showed a high content of -carotene, which decreased during drying temperature between 40 degrees C and 80 degrees C. Free and bound phenolic acids were also determined, showing gallic acid to be the prevalent phenolic acid. Total phenolic and flavonoid contents in the dried berries showed a higher decrease at lower temperature due to longer drying time. The radical-scavenging activity also showed higher antioxidant activity at higher drying temperatures (70-80 degrees C) than at lower drying temperatures (40-50 degrees C). Total phenolic content (TPC) and flavonoids showed good correlation with antioxidant capacity. Murta berries proved to be an excellent source of antioxidants and bioactive compounds and are therefore a potential ingredient for new functional food products.