木奈果实低温贮藏１２ｄ各处理的多酚氧化酶（ＰＰＯ）活性、酚类物质含量和细胞膜透性变化较小。贮藏２４ｄ各处理的细胞膜透性急剧增加，ＰＰＯ活性亦急剧升高，氧化酚类物质而使其含量急剧下降，导致果肉发生褐变。贮藏３６ｄ各处理的ＰＰＯ活性下降，膜透性仍继续增加。在整个贮藏过程中减压处理的ＰＰＯ活性、酚类物质含量和细胞膜透性变化最小，贮藏３６ｄ的果肉褐变率最低 The activities of polyphenol oxidase (PPO), contents of phenolic substances and membrane permeability of M. japonica fruits stored at low temperature for 12 days were little changed. After 24 days of storage, the membrane permeability increased rapidly and PPO activity increased sharply. Phenolic compounds were oxidized and its content dropped sharply, resulting in browning of the pulp. The PPO activity of all treatments decreased after storage for 36 days, and membrane permeability continued to increase. The changes of PPO activity, phenolic content and cell membrane permeability during the whole storage process were the least, with the lowest browning rate