The aim of this study was to evaluate the impact of ultrasound (US) at different frequencies (20, 370, and 583kHz) and power levels (35 and 48W) on the residual activity (RA) of peroxidase (POD) and polyphenol oxidase (PPO) in strawberry puree. Total anthocyanin content (TAC), total phenolic content (TPC), ferric ion reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) were also assessed. Results. Were compared with untreated, thermally treated at 40 °C (control) and pasteurized (90 °C) strawberry puree. POD and PPO RA were significantly (P<0.05) reduced, whilst there was a significant (P<0.05) increase in TAC (5%-19%) in all US-treated samples in comparison with the untreated samples and the controls. US at 20kHz (35W) increased significantly (P<0.05) TPC (9%) and FRAP (6%) in strawberry puree, whereas the effect of 583kHz (48W) on these parameters was insignificant (P>0.05). Pasteurization inactivated POD...

You do not currently have access to this content.