To extend the shelf life of button mushrooms, the optimal fumigation doses for hydrogen gas treatment were screened through sensory evaluation, combined with browning index and weight loss rate in this study. Then, using H₂ fumigation combined with polyethylene film packaging as a control, changes in the sensory quality, reactive oxygen species, browning-related enzyme activity and the nutritional quality of mushrooms treated by H₂ fumigation combined with nano-film packaging (H₂ + NA) during low-temperature storage were dynamically tracked. The preservation effect of H₂ + NA on mushrooms after harvest was investigated, and its mechanism was also analyzed. The storage validation test showed that the optimum H₂ fumigation time was 2 h, and the H₂ + NA-treated mushrooms had a fuller appearance, maintained whiteness well, showed a slow increase in reactive oxygen species, antioxidant enzyme activities remained at high levels, a high retention rate of protein content was observed, and there was a good antibacterial effect. This study indicates that H₂ fumigation combined with nano-film packaging can improve the storage quality of button mushrooms and may prolong low-temperature shelf life by 4–5 d compared to conventional commercial polyethylene film packaging.

Stipe elongation is one of the main characteristics of the postharvest quality deterioration of Flammulina velutipes fruiting bodies. In order to reduce the postharvest stipe elongation of F. velutipes and prolong its shelf life, in this study, using polyethylene (PE) packaging and unpackaged treatments as controls, the effects of a polyethylene nano-packaging on postharvest stipe elongation of F. velutipes were investigated and its regulatory mechanisms were explored from the physiological and biochemical aspects. The results showed that the CO₂ content in polyethylene nano-packaging boxes was higher than in control boxes, and the O₂ content was lower than in the control group, indicating that nano-packaging could reduce F. velutipes respiration during low-temperature storage. The stipe elongation rate, chitinase activity, and β-1,3-glucanase activities of F. velutipes were lower in the nano-packaging group than in PE-packaged and unpackaged control groups, and the nano-packaging inhibited the increase in chitin and β-glucan, the main components of the cell wall. The levels of auxin (IAA), abscisic acid (ABA), gibberellin (GA), and cytokinin (CTK) were also lower in the nano-packaged group than in controls at most timepoints. After 18 d of storage, polyethylene nano-packaging inhibited the stipe elongation of fruiting bodies, and maintained mushroom quality, with stipe elongation of only 34.7% and 76.7% of PE-packaged and unpackaged control groups, respectively. The results showed that nano-packaging could effectively inhibit the harvest stipe elongation and prolong the shelf quality of F. velutipes.