Abstract: The purpose of this study was to evaluate age-related changes in antioxidant enzyme activities in modified atmosphere packaged (MAP) golden needle mushroom under varying oxygen content conditions during storage at 1－3 ℃. Totally 100 g of golden needle mushroom was placed into polyethylene bags containing 8 g of hygroscopic bentonite and 6 g of activated carbon, in which different modified atmospheres were formed by 0% O2 + 100% N2, 20% O2 + 80% N2, 50% O2 + 50% N2, 70% O2+ 30% N2, 80% O2 + 20% N2, 90% O2 + 10% N2 and 100% O2 + 0% N2 before storage. Sampling was conducted for determination of antioxidant enzyme activities every 5－7 days. The results showed that modified atmosphere containing 80% O2 had the best fresh-keeping effect on golden needle mushroom. The activities of superoxide dismutase (SOD), catalase (CAT) and lipoxygenase (LOX) were increased obviously, while the activities of polyphenol oxidase (PPO), peroxidase (POD) and cellulase (CMCase) displayed an opposite change in the first 2 weeks. With the continuous prolongation of storage, the activities of SOD, CAT and LOX declined remarkably, while POD and PPO showed a significant increase. As a result, superoxide anion and hydroxyl free radicals were accumulated in golden needle mushroom, which leads to the damage of cell membrane structure and the increase in cellular permeability. In conclusion, water seepage and tissue softening resulting from the decomposition of cell-wall by CMCase and the aggravation of enzymatic browning may be the major causes of senescence and quality deterioration in golden needle mushroom.

Key words: golden needle mushroom, high oxygen atmospheres packing (HOAP), antioxidant enzyme system, fresh-keeping, senescence