Comparative study of two cold plasma technologies on apple juice antioxidant capacity, phenolic contents, and enzymatic activity

Cold plasma technologies are being developed as an alternative to thermal processes aiming toward preservation while retaining or improving several quality parameters. This research evaluates the use of dielectric barrier discharge (DBD) plasma and glow discharge plasma on browning enzyme activity, antioxidant capacity, and total phenolic content of apple juice. This work evaluated the effects of the main DBD plasma operating conditions, such as excitation frequencies (50–900 Hz), and glow plasma discharge operating conditions, such as air plasma flow rates (10–30 ml/min) and processing time (10–30 min). Both plasma systems partially inactivated the enzymes polyphenol oxidase and peroxidase and consequently increased apple juice's total phenolic content and antioxidant activity. DBD plasma technology presented better efficacy in increasing apple juice's total phenolic content and antioxidant capacity. DBD plasma and glow discharge plasma have the same effectiveness in inactivating browning enzymes in apple juice. Novelty impact statement This work compares two cold plasma technologies for apple juice processing. The results showed that different plasma technologies lead to different outcomes and that the right choice of technology should be made for a given goal.