Investigating effects of air-cold plasma jet on enzymatic activity and nutritional quality attributes of Mangosteen (Garcinia mangostana L.) juice

This study aimed to investigate the effects of air-cold plasma jet processing on the quality of mangosteen juice using an experimental design that varied the duty cycle of the power source (30%-70%), air flow rate (1-5 L/ min), and treatment time (2-10 min). Changes in pH, color, ascorbic acid (AA), anthocyanin, flavonoid, phenolic content, enzyme activities, and antioxidant activity were evaluated. The cold plasma jet treatment substantially inactivated polyphenol oxidase, reducing its activity by up to 60% across all tested conditions, while peroxidase activity exhibited varying responses. The optimal treatment conditions (60% duty cycle, 4 L/min air flow rate, and 4 min treatment time) maximized bioactive compound levels, resulting in an 87.75% increase in AA content, along with substantial increases in total anthocyanins, phenolic content, and flavonoids. Cold plasma jet improved antioxidant activity, particularly in the DPPH radical scavenging activity. No notable change in color was observed. This study highlights the effectiveness of cold plasma technology for processing mangosteen juice while preserving its essential nutritional and physical qualities. The method offers a promising nonthermal alternative for maintaining the quality of high-value processing-sensitive mangosteen juice.