Impact of surface dielectric barrier discharge cold atmospheric plasma on quality and stability of fresh-cut iceberg lettuce

This study evaluated the impact of cold atmospheric plasma (CAP) on fresh-cut iceberg lettuce (FIL) quality and stability. CAP treatments were performed using a Surface Dielectric Barrier Discharge, applying 6 kV at 23 kHz and exposition times varying from 15 to 60 min. FIL was analysed before and after treatments for polyphenoloxidase (PPO) and peroxidase (POD) activity, microbial contamination, colour, surface microstructure properties, chlorophylls content, polyphenols (TPC), ascorbic acid (AA), and antioxidant activity (AoA). TPC, AA and AoA were evaluated also after storage (4 degrees C for 5 days). CAP treatments provoked a reduction of PPO and POD activity with a processing time- and ozone-concentration-dependent effect. After treatments, a slight inactivation of mesophilic and psychrotrophic bacteria was observed, while yeast counts remained unaffected. With increasing treatment times, increasing cell damages and colour variations were detected, and a decrease of chlorophylls, TPC, AA, and AoA. After storage, an overall AoA increase was observed due to increased extractability or production by living cells of antioxidant compounds. These findings provide insights into the efficacy of CAP treatment in preserving fresh-cut iceberg lettuce quality. Further investigations are needed to optimize the process conditions and increase microbial inactivation while limiting qualitative damage to the product.