The effect of indirect plasma-processed air pretreatment on the microbial loads, decay, and metabolites of Chinese bayberries

Abstract

Chinese bayberries are nutritious and have a unique flavor. However, they are prone to mechanical damage after harvest, which leads to increments of microbial growth on the surface, promoting fruit decay and causing potential health hazards. This study evaluated the decontamination effects of plasma-processed air (PPA) on natural occurring microbiota (Test I) and inoculated Penicillium citrinum (Test II) of both intact and mechanically damaged Chinese bayberries over three days of storage at 20 °C. In addition, the effects of PPA pre-treatment on metabolites of Chinese bayberries were investigated. In Test I, the results show that, for the intact fruits, compared to the control, the PPA pretreatment reduced the decay index, fungi populations, and bacteria populations by 19.72%, 1.69, and 1.15 log CFU/g at the end of storage, respectively, whereas, for fruits with compression damage, those values were 11.92%, 1.23, and 1.33 log CFU/g, respectively. In Test II, the results show that PPA inhibited the mycelial growth of Penicillium citrinum and reduced the decay indices. The results of metabonomics analysis show that PPA pretreatment caused oxidative stress of Chinese bayberries, increasing the contents of antioxidative compounds and enhancing the antioxidant activity of Chinese bayberries.