Ultrasound effects on fruit juice enzymes: a meta-analytic study for the polyphenol oxidase

This review aims to investigate and analyze the effect of ultrasound process variables on polyphenol oxidase (PPO) enzymatic activity. The data obtained from Portuguese published articles found on Web of Science, PubMed and Wiley in the period from 2013 to 2021 were used for making the table overview and meta-analysis of results described in those studies. Study selection was conducted with the PRISMA method. There were 19 relevant studies and 140 data used for meta-analysis. In general, the results show that the use of ultrasound increased or reduced the enzymatic activity of PPO. The processing time, potency, amplitude, frequency, temperature and ultrasound intensity were significant in enzyme denaturation. The findings show that the ultrasound process variables should be considered to evaluate the effect on the modification of the PPO enzymatic activity of the treated juices, affirming that the technique can be effective in preserving the quality of processed foods.