Effects of glow plasma technology on some bioactive compounds of acerola juice.

This work examines the influence of glow plasma technology on vitamins, carotenoids, phenolic content, antioxidant capacity, and color of acerola juice. The effects of nitrogen plasma treatment were observed at different operation conditions: flowrates (from 10 to 20 mL/min) and processing times (5 to 15 min). The study explored the suitability of glow plasma on 40 mL samples, which is considered a large sample of current plasma technology studies. Nitrogen glow plasma increased the content of vitamin A and carotenoids in acerola juice under specific processing conditions. The highest increase of vitamin A and carotenoids was found at gas flow rate of 10 mL/min and 10 min of treatment time. The effect of glow plasma on vitamin C (main vitamin in acerola juice) was not significant, maintaining the retention of vitamin C above 95% under all operating conditions that were studied. The phenolics content reduced by 30% due to reaction with reactive nitrogen species when the juice was treated at the most severe condition (gas flow rate of 20 mL/min and 15 min of treatment time). The antioxidant capacity was little affected by the reactive nitrogen species formed by N2 glow plasma, which remained relatively constant at high plasma flow rate (20 mL/min) but reduced when lower gas flow rates were used (10 mL/min). The typical orange color of the juice improved due to the increase in free carotenoid content. In summary, this study showed that the operating conditions of glow plasma treatment could be adjusted to have a positive influence on vitamin A, carotenoids and color of acerola juice.