Effect of low intensity direct-current electric field on anti-browning of apple juice: Enzyme inactivation kinetics and juice properties

For the first time, the efficacy of low intensity (1–7 V/cm) direct-current (DC) electric field in preventing browning in apple juice is examined. The results show that applying a 5 V/cm electric field can inactivate 89.24% of polyphenol oxidase (PPO) within 90 min and achieve complete inactivation of peroxidase (POD) within 70 min, maintaining the juice temperature below 30 °C throughout the process. The Weibull model fits the PPO and POD inactivation effectively, suggesting varied responses among isoenzymes. Under the optimal conditions (5 V/cm for 90 min), a 15.89% increase in total phenolic content (TPC) was observed alongside significant improvements in antioxidant activity. Furthermore, this method preserved the natural flavor and lightened the color of the apple juice, enhancing its sensory appeal. These findings indicate that low intensity DC electric field is an innovative and effective choice for preventing juice browning, offering significant potential for application in the food industry.