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.

In order to quickly and effectively identify the slight damage of white button mushroom (Agaricus bisporus), the near-infrared hyperspectral images (400‒1000 nm) of the intact mushroom and the mushroom with different degrees of damage caused by vibration for 60 and 120 s were recorded. It was found that the spectra of the three types of samples in the wavelength range 450‒750 nm were obviously different. Compared to standard normal variable transformation and multivariate scattering correction, Savitzky Golay (SG) smoothing was determined as a better pretreatment method. The successive projection algorithm (SPA) and competitive adaptive reweighted sampling (CARS) were applied to extract the vibration-specific wavelengths. Based on the gray-level co-occurrence matrix, the texture features of the region of interest of the feature image at 500 nm were extracted. A model to discriminate the degree of damage of mushrooms was established using partial least square discriminant analysis (PLS-DA), BP neural network and extreme learning machine (ELM) based on the spectral information and the texture feature information, separately. The results showed that the PLS-DA model with each of the two feature sets as input had better performance than the other two models. With the spectral information as input, the average recognition accuracies for the training set and the test set were 93.33% and 91.11%, while those with the texture feature information as input were 88.89% and 86.67%, respectively. Finally, a PLS-DA classification model was established based on the spectrum-texture fusion information, whose overall classification accuracies for the training set and the test set were 97.78% and 95.56%, respectively. The predictive performance of the model based on the spectrum-texture fusion information was better than the model based on the single information. Therefore, the application of spectrum-texture fusion information-based modeling can improve the detection accuracy of white button mushrooms with different degrees of damage, which provides theoretical support for the storage and classification of white button mushrooms.

Agaricus bisporus tastes good and is nutritious, but its respiratory metabolism is strong and consequently its shelf life is short. In order to solve the problem of its poor storability, Agaricus bisporus was stored for a short period of time under oxygen-free modified atmospheres containing different levels of CO₂ (5%, 10% and 20%) or a pure nitrogen atmosphere as a control and evaluated for postharvest quality indicators (mass loss, lightness, browning degree, texture, and taste value) and physiological indicators (respiration rate, relative conductivity, malondialdehyde (MDA) content, antioxidant contents). We found that a low-CO₂ (5%) atmosphere was the most effective in preserving the quality of Agaricus bisporus, which could reduce the respiration rate and mass loss, inhibit browning, maintain firmness and springiness, delay the increase of cell membrane permeability, reduce oxidative damage and maintain the umami taste of Agaricus bisporus. But the preservation effect of a high-CO₂ atmosphere was relatively poor, and the mushroom stored under a 20% CO₂-containing atmosphere showed serious browning, increased cell membrane permeability and consequently serious electrolyte leakage, accompanied by oxidative damage.