Effects of Postharvest Brassinolide Treatment on the Metabolism of White Button Mushroom (Agaricus bisporus) in Relation to Development of Browning During Storage

Postharvest browning is the primary cause of a decrease in the shelf life of the white button mushroom (Agaricus bisporus). This study investigated the effect of postharvest brassinolide (BL) treatment on metabolism in relation to browning of the white button mushroom. Each harvested mushroom was dipped into one of three solutions containing 0, 1, or 3 mu M BL for 5 min and stored in darkness at 4 degrees C for 16 days. Our results indicated that treatment with BL restrains browning development and reduces the total phenolic content and polyphenol oxidase activity. In addition, BL treatment maintains lower weight loss, electrolyte leakage, and malondialdehyde content and inhibits any increase in lipoxygenase activity compared with those of the control mushrooms. Furthermore, BL treatment significantly decreases the accumulation of reactive oxygen species (ROS) and induces the antioxidant enzyme system. Compared with 1 mu M BL, treatment with 3 mu M BL is more effective in reducing cap browning. The reduction of membrane oxidative damage and ROS levels induced by BL inhibits enzymatic browning reaction in the white button mushroom. These findings suggest that treatment with BL could have the potential of inhibiting browning and thus maintaining the mushroom's commercial value.