Effect of Cold Plasma and Microwave Pretreatments Combined with Hot-Air Drying on Physical Properties, Chemical Composition, and Volatile Profile of Pomegranate Peels

The use of non-thermal drying techniques for preserving fruits and vegetables has gained popularity due to their ability to enhance dried products' quality, reduce drying time and energy consumption, and increase efficiency. In this study, the effects of cold plasma (CP) and microwave (MW) pretreatments combined with hot air drying (HAD) on the chemical composition (amino acid, sugar, organic acid, mineral, and volatile) and physicochemical properties of dried pomegranate peels were investigated. For this purpose, dry samples were compared with fresh ones. The results showed that CP pretreatment is the best technique for preserving the chemical, physical, and nutritional quality of pomegranate peels. Scanning electron microscopy (SEM) images showed that CP pretreatment significantly changed the surface morphology of pomegranate peels, leading to faster drying rates. This study also found no significant changes in color parameters in CP-HAD peels. Consequently, this study showed that cold plasma is a promising, environmentally friendly, and innovative technology that provides a great advantage in preserving food quality.