Effect of atmospheric cold plasma treatment on antioxidant activities and reactive oxygen species production in postharvest blueberries during storage.

BACKGROUND: Blueberry is universally acknowledged as a kind of berry rich in antioxidants. Cold plasma, an emerging non-thermal treatment technology, has been proved to be able to maintain or improve the antioxidant level while inactivating the microorganisms on the surface of fruits and vegetables. Postharvest blueberries were treated with atmospheric cold plasma (ACP; 12 kV, 5 kHz) for 0 s (Control), 30 s (ACP-30), 60 s (ACP-60), and 90 s (ACP-90) in this study, and the effects of ACP on the antimicrobial properties, antioxidant activities, and reactive oxygen species (ROS) production were investigated during storage at 4 ± 1 °C for 40 days.

RESULTS: Total aerobic bacteria and mold populations on ACP-treated blueberries decreased significantly in a time-dependent manner (P < 0.05), and decreased by 0.34-1.24 and 0.57-0.87 log10 CFU g-1 respectively on ACP-60-treated blueberries during storage. The decay rate of blueberries was decreased by 5.8-11.7% and the decrease of blueberry firmness was slowed down by ACP-60. But the total phenol, anthocyanin, and ascorbic acid contents increased, and superoxide dismutase, catalase, and peroxidase activities were enhanced in ACP-treated blueberries. The free radical scavenging activity and total antioxidant capacity (T-AOC) were enhanced. Hydrogen peroxide (H2 O2 ) and superoxide anion (O2 - ) production rates declined by 27.3% and 41.3% at day 40 of storage, respectively.

CONCLUSION: It is suggested that ACP may be a promising non-thermal treatment technology for postharvest sterilization and preservation of blueberry under suitable conditions. © 2020 Society of Chemical Industry.