Low pressure cold plasma treatment for microbial decontamination, improvement of bioaccessibility and aroma profile of dried red peppers

This study aimed to examine the impact of low-pressure cold plasma treatment (CPT) on the microbial decontamination efficacy, color, total phenolic content and antioxidant capacity after in vitro digestion, morphological and chemical properties, capsaicin content and volatile profile of four different dried red peppers including red pepper flakes, chili pepper, paprika pepper, and isot pepper flakes (produced from red pepper flakes by tempering). Three different cold plasma durations of 10, 20, and 30 min were applied to dried red pepper samples. The findings indicate that CPT decreased the total mesophilic aerobic bacteria (TMAB) by 0.37-1.41 log CFU/g and total yeast and mold (TYAM) count by 0.70-2.68 log CFU/g. The highest reduction of TMAB and TYAM was observed in dried red and isot peppers, respectively. However, CPT caused an important change in the color of the dried pepper powder compared to the flakes. According to the results obtained, the CPT time was chosen as 20 min for dried chili, paprika, and isot pepper, whereas 10 min was designated for dried red pepper flakes. Under these selected conditions, no significant changes were observed in the morphological and chemical properties of the samples. The capsaicinoids content in the pepper sample diminished following CPT treatment, with a more significant drop observed in the powdered samples. The study demonstrates the efficacy of low-pressure cold plasma (LPCP) in decontaminating and enhancing the bioaccessibility of total phenolic content and antioxidant capacity in dried red pepper samples. Moreover, chemical and morphological properties of the samples were assessed. The concentrations of volatile compounds γ-terpinene, p-cymene, and sulcatone were changed after CPT.