Impact of In-Package Cold Plasma Treatment on Physicochemical Properties and Shelf Life of Button Mushrooms (Agaricus bisporus)

Abstract

The button mushrooms were sealed inside a package with three different gas combinations, viz. 80 % O2 + 10 % CO2 + 10 % N2 (MAP1), 10 % O2 + 10 % CO2 + 80 % N2 (MAP2), and 10 % O2 + 80% CO2 + 10 % N2 (MAP3). The packaged samples were treated with cold plasma (CP) for 15 min at 28 kV and then stored at 4 °C for 7 days. Microbiological analysis, and physicochemical properties of button mushrooms were measured on days 1, 4, and 7 from the day of treatment. Then the results were compared to untreated samples (Control), samples treated with direct cold plasma (DCP), and mushrooms packed in three different MAP compositions. Microbial reductions of approximately 0.93 and 1.14 log CFU/g in total bacterial count, and 1.07 and 1.24 log CFU/g in yeast and molds were noticed following DCP and in-package CP treatment, respectively. PPO activity was effectively reduced by in-package CP treatment, resulting in lower browning values of mushrooms upon completion of the storage period. Changes in physicochemical properties of button mushrooms were not significant between control, DCP-treated and in-package CP treated mushrooms on day 1. In-package CP treatments with three different gas combinations exhibited the same effects on the reduction of microorganisms, but MAP with high oxygen showed somewhat larger reductions than the other two gas combinations. At the end of storage, all in-package CP treated button mushrooms maintained significantly (p<0.05) better quality characteristics than control and DCP treated mushrooms. The button mushrooms treated with CP and kept in a high oxygen gas concentration exhibited better quality characteristics than other gas combinations. So, in-package cold plasma treatment with a high oxygen concentration might be used to decontaminate button mushrooms while maintaining product quality.