Optimization of cold plasma processing conditions for fresh-cut kiwifruit slices by using response surface methodology.

The work aims to optimize the process of cold plasma for fresh-cut kiwifruit. The effects of discharge times, treatment voltages, and slice thickness as well as the interaction between them were investigated. Factor analysis was used to screen out the characteristic indices of fresh-cut kiwifruit. Design-Expert software was used to design three-factor response surface tests and find the optimal parameters. The results revealed that the quality indices of fresh-cut kiwifruit were the color difference, brittleness, and solid-acid ratio, the established binomial regression equations were significant (P < 0.05). At the optimal level: 26 kV treatment voltage, 120 s discharge times, and 10 mm slice thickness, the optimized test values for the color difference, brittleness, solid-acid ratio and decreased logarithm value of total plate count were 2.25, 128.96 g·s, 18.03 and 2.30 lg(CFU·g^-1), respectively. Cold plasma could significantly improve the inactivation of bacteria in fresh-cut kiwifruit.