Changes in color, antioxidant, and free radical scavenging enzyme activity of mushrooms under high oxygen modified atmospheres

The effects of high oxygen concentration (80% O2) on color, antioxidant enzyme and free radical scavenging activity of mushrooms (Agaricus bisporus) were investigated. High oxygen modified atmosphere chambers were designed. Mushrooms (A. bisporus) were held at 2 °C for 12 d in modified atmosphere chambers, linked by separate lines to continuous flow (1.67 mL s−1) of humidified air (control) and 80% O2 (balance N2). Browning of mushroom flesh and surface exposed to 80% O2 was prevented and the expected increase in membrane permeability and lipid peroxidation was delayed. Compared to the control treatment, high oxygen significantly inhibited the reactive oxygen species (ROS) such as O2− and H2O2. The corresponding oxygen radical scavenging enzyme activities including SOD, CAT and POD in 80% O2 were also higher than those in the control (P < 0.05). Higher antioxidant activity was found in high oxygen treated mushrooms. The treatment with 80% O2 could be used in modified atmosphere of mushrooms to avoid browning, which was due to enhanced antioxidant and free radical scavenging enzyme activity.

► Effects of high oxygen on color, antioxidant enzyme and free radical scavenging activity of mushroom were examined. ► Browning of mushroom was prevented. ► Increase in membrane permeability and lipid peroxidation was delayed. ► Oxygen radical scavenging enzyme activities in 80% O2 were higher. ► Higher antioxidant activity was found in high oxygen.