UV-C treatment inhibits browning, inactivates Pseudomonas tolaasii and reduces associated chemical and enzymatic changes of button mushrooms

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 degrees 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 gamma-l-glutaminyl-4-hydroxybenzene (GHB), gamma-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. (c) 2021 Society of Chemical Industry.

Automated summary

The study showed that UV-C treatment can effectively inhibit browning, inactivate P. tolaasii, and reduce the associated chemical and enzymatic changes in button mushrooms.