Effect of Re-oxygenation Environment on the Postharvest Quality of Agaricus bisporus

This study aimed to explore the effects of re-oxygenation environments with different O₂ levels after anaerobic treatment on the postharvest quality of Agaricus bisporus in order to provide a theoretical basis for the application of anaerobic treatment technology for the storage and preservation of Agaricus bisporus. Mushrooms were treated with pure N₂ for six hours, and then re-oxygenation environments with different O₂ levels were established through microporus modified atmosphere packaging (MAP). The respiration rate, ethylene production, anaerobic metabolite contents, mass loss percentage, appearance, texture and sensory characteristics of the mushroom samples were analyzed during storage. Ultralow O₂ environments (1%–2%) significantly inhibited the production of ethylene during storage. On the 15^th day of storage, the mass loss percentage was only 1.38%, and the firmness and springiness were higher than those of the initial values by 36.38% and 5.02%, respectively. Furthermore, the mushrooms did not show obvious browning and maintained the highest sensory score during the entire storage period. However, high O₂ environments (19%–20%) accelerated the deterioration of mushroom quality. Brown spots and decay were observed on the surface of mushrooms on the 9^th day. The sensory scores for color, stickiness, flavor, texture, and decay were the lowest on the 15^th day. Therefore, ultra-low O₂ re-oxygenation environments can better maintain the quality of Agaricus bisporus by inhibiting the biosynthesis of ethylene.