Abstract: In order to explore the physiological mechanism for the inhibition of its browning by natamycin, fresh-cut Agaricus bisporus was dipped in deionized water, 0.1 g/kg natamycin alone or in combination with 10 g/kg D-sodium ascorbate for 5 min, and then stored at 4 ℃. Physiological indexes?such as polyphenol oxidase (PPO) and tyrosinase (TYR) activities, and free radical scavenging capacity were analyzed during storage. The results showed that natamycin alone and in conjunction with D-sodium ascorbate effectively suppressed the decrease of hardness and the increase of mass loss, respiratory intensity and relative conductivity in fresh-cut mushroom, reduced the total number of molds and yeasts, and delayed the increase of PPO and TYR activities. Meanwhile, both treatments maintained the contents of VC, and reduced glutathione (GSH), total phenols and hydroxyproline (HYP) and the activities of glutathione reductase (GR) and phenylalanine ammonialyase (PAL). Hence, the two treatments were able to maintain higher levels of antioxidant enzyme activity, free radical scavenging capacity and total antioxidant capacity, thereby inhibiting browning and?prolonging the shelf-life of fresh-cut Agaricus bisporus. The combined treatment was more effective than natamycin alone.

Key words: fresh-cut Agaricus bisporus, browning, inhibitory mechanism, polyphenol oxidase, antioxidant system