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BACKGROUND: Agaricus bisporus with a completely white appearance is popular with consumers. However, A. bisporus is susceptible to senescence and spoilage, which results in browning and oxidative tissue damage, with limited shelf life. This study investigated the effects of shortwave ultraviolet (UV‐C, 1.0 kJ m−2) irradiation on quality features, enzymatic browning, and defense properties of A. bisporus stored at 4 °C for 21 days. RESULTS: After storage, UV‐C irradiated A. bisporus had increased quality of sensory, color and hardness characteristics; it exhibited higher content of total phenolic, brown melanin precursors, including γ‐glutaminyl‐4‐hydroxybenzene, γ‐glutaminyl‐3,4‐dihydroxybenzene and tyrosine, lower accumulation of malondiadehyde, hydrogen peroxide and superoxide radical, and maintained membrane integrity in comparison to control samples. Besides, A. bisporus treated by UV‐C showed lower degree of browning and higher level of self‐defense capacity, which may be ascribed to the enhancement in activities of superoxide dismutase, catalase, phenylalanine ammonia lyase, chitinase and β‐1,3‐glucanase activity, while inhibiting polyphenol oxidase activity during storage. CONCLUSION: These results indicate that the higher self‐defense capacity with UV‐C treatment might be the mechanism associated with the delay of senescence in Agaricus bisporus. Therefore, UV‐C treatment is suggested as a potential practical application in mushrooms. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND Button mushrooms with completely white appearance are popular with consumers. However, button mushrooms are susceptible to infection with Pseudomonas tolaasii, which results in browning. This study evaluates the effects of ultraviolet‐C (UV‐C) treatment on the inactivation of P. tolaasii in vitro and in vivo and on the physiological and chemical changes of button mushrooms during storage for 21 days at 4 °C. RESULTS: UV‐C doses of 0.5 to 9.0 kJ m−2 resulted in 3.91–6.26 log CFU mL−1 reduction of P. tolaasii populations in vitro, and UV‐C treatment reduced P. tolaasii populations inoculated on mushroom cap surfaces and browning severity. Moreover, P. tolaasii increased polyphenol oxidase (PPO) activity, and decreased phenylalanine ammonia‐lyase (PAL) activity, the accumulation of phenolics and contents of brown melanin precursors, including γ‐l‐glutaminyl‐4‐hydroxybenzene (GHB), γ‐l‐glutaminyl‐3,4‐dihydroxybenzene (GDHB), and tyrosine in button mushrooms. UV‐C treatment was found to reduce the negative changes due to P. tolaasii infection. CONCLUSION: These results indicated that the application of UV‐C treatment inhibited browning, inactivated P. tolaasii and reduced P. tolaasii – associated chemical and enzymatic changes of button mushrooms. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]