Characterization of bioactive films loaded with melatonin and regulation of postharvest ROS scavenging and ascorbate-glutathione cycle in Agaricus bisporus

Abstract

Bioactive packaging has a good development prospect owing to its protecting environment and preserving products. Melatonin is a natural, non-toxic, and odorless green preservative. In this study, three types of biologically active films were developed utilizing melatonin concentrations of 30 mM, 60 mM, and 90 mM. The results showed that the mechanical, barrier and thermal properties of the G/T/M-60 film were comparatively good. Additionally, no damage to the film matrix was observed after adding melatonin to the G/T/M-60 film, and the melatonin molecules were wrapped in the matrix. Therefore, we selected the G/T/M-60 film for melatonin release and packaging of Agaricus bisporus. Compared with the control group, the G/T/M-60 maintained the whiteness and hardness of white mushrooms, and decreased the respiratory rate, hydrogen peroxide, superoxide anion levels. It not only inhibited the activity of polyphenol oxidase (PPO), but also maintained high activities of antioxidant enzymes. Further, the G/T/M-60 regulated the AsA-GSH circulatory system, greatly increased the ascorbic acid and glutathione content, and provided sufficient substrate for the circulatory system, which effectively removed excess reactive oxygen species, and thereby reduced the damage to membrane lipids in the mushrooms. In brief, the G/T/M-60 packaging effectively maintained the quality and delayed the senescence of postharvest white mushrooms, which provides new insights and technical guidance for the preservation of mushrooms and exploration of bioactive packaging.