Effects of cold plasma on color changes, anthocyanins content and microbial quality of barberry juice

The aim of present study was therefore to investigate the effect of different duty cycles (8, 12 & 16%) at different times (2.5, 5 & 10 min) of plasma treatment on anthocyanin content, color change and microboal quality of barberry juice in comparison with thermally pasteurized (80 °C for 2 min) and untreated samples. The results showed that all plasma-treated samples possessed higher anthocyanin content as well as greater L* and a* values than thermally-treated and untreated samples (p≤0.05), regardless of duty cycles and treatment times; This superiority was, however, more pronounced (p≤0.05) for the longer plasma treatments. Likewise, the longer plasma treatment was accompanied by significant decrease in total microbial count as well as yeasts and molds count (p≤0.05) of barberry juice. It was observed that the improving effect of prolonged plasma treatment on microbial quality of barberry juice was intensified at higher duty cycles. However, the microbial quality of plasma-treated barberry juice was far lower than that of thermally pasteurized sample. The results of this study show that the barberry juice treated with cold atmospheric plasma had higher nutritional value and more desirable color than thermally pasteurized one but despite the decrease in contamination, failed to meet the requirements of ISIRI for microbial quality.