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采用急降温和缓降温两种方法处理鸭梨果实，并对冷藏中果心褐变指数、保护酶活性、膜质过氧化水平和细胞内膜微粘度进行测定。结果表明：急降温处理的果实约３０天果心出现褐变症状，６０天后褐变指数达到１００％，而缓降温处理的果实在贮藏中无褐变产生。在６０天的贮藏过程中，急降温处理的果实果心组织的超氧化物歧化酶（ＳＯＤ）、过氧化物酶（ＰＯＤ）、过氧化氢酶（ＣＡＴ）活性均呈下降趋势，丙二醛（ＭＤＡ）水平和细胞内膜微粘度则显著升高。缓降温果实果心组织中ＳＯＤ、ＰＯＤ活性呈上升趋势，ＣＡＴ活性虽呈下降趋势，但下降水平明显低于急降温处理。ＭＤＡ水平及细胞内膜微粘度的上升率明显低于急降温处理组。实验结果说明：急降温处理导致果心细胞膜质过氧化作用加剧，同时造成细胞内膜流动性下降，从而造成细胞膜系统组分及功能发生变化，导致细胞中区域化分布被打破，造成果实组织褐变。
The fruits of Yali pear were processed by two methods: rapid cooling and gentle cooling, and the determination of browning index, protective enzyme activity, membrane lipid peroxidation and intracellular microviscosity of frozen fruits were carried out. The results showed that browning appeared in the fruit of emergency cooling treatment for about 30 days and browning index reached 100% after 60 days, while browning treatment did not produce browning during storage. During 60 days of storage, the activities of SOD, POD and CAT decreased significantly in the heart of the fruit treated with the rapid cooling treatment. The malondialdehyde (MDA) levels and intracellular microviscosity were significantly increased. The activities of SOD and POD in the fruits of slow-cooling fruit were increased, while the activities of CAT decreased, but the levels of SOD decreased obviously. The level of MDA and the increase of intracellular microviscosity were significantly lower than those of the acute cooling group. The results showed that acute cooling led to aggrandizement of membranous peroxidation in fruit heart cells and decreased the fluidity of the endomembrane, resulting in the changes of the components and functions of the cell membrane system, resulting in the breakdown of the regionalization of the cell membrane, resulting in browning of the fruit tissue change.