Cold Plasma Treatment of Orange Juice Using Multipin-Plane Electrical Discharge

Abstract

Cold plasma technology, a nonthermal food processing approach, has garnered attention for its ability to inactivate microorganisms and enzymes while preserving sensory and nutritional qualities. This study investigates the effects of multipin-plane cold plasma treatment on orange juice's microbiological and physicochemical properties. Juice samples were treated at varying voltages (20, 25, and 30 kV) for up to 10 min, with measurements taken for microbial load, enzyme activity (pectin methylesterase), color, browning index, cloud value, and ascorbic acid retention. The Weibull model was used to describe microbial and enzyme inactivation kinetics. Results showed significant microbial reduction, especially at higher voltages, with the total aerobic mesophiles being more susceptible than yeast and molds. Enzyme inactivation followed a concave-shaped curve, suggesting rapid initial degradation. Despite effective microbial inactivation, higher voltages led to noticeable color changes, browning, and ascorbic acid degradation. The study demonstrates that cold plasma can serve as an effective preservation method, especially for extending the shelf life of juice from late-stage, unsold oranges, while highlighting the trade-offs between microbial safety and quality attributes at higher-voltage levels.