High pressure homogenization (HPH) and ultrasound with (US_ct) or without (US) temperature control were applied to apple juice individually or in combination for inactivating polyphenoloxidase (PPO). Ten passes HPH at 150 MPa were needed to achieve 50% PPO inactivation. US_ct led to 90% PPO decrease at the longest time (45 min), whereas total enzyme inactivation was achieved by subjecting samples to 6 min US. Results showed that temperature affected enzyme inactivation rather than the process applied. Moreover, the HPH-US_ct and HPH-US combined treatments led to enzyme residual activities similar to those caused by the application of HPH and US_ct, and US individual treatments, respectively. US provided to the apple juice less energy density to obtain PPO inactivation than US_ct and HPH, due to the contribution of the in situ generated heat. Also, US showed the lowest energy consumption, thus confirming its appropriateness.