鲜茶汁贮藏过程中多酚氧化酶活性分析

鲜茶汁在贮藏过程中极易酶促褐变采用分光光度法研究了温度pH 值及浓度抑制剂对鲜茶汁中多 酚氧化酶（PPO）活性的影响结果表明院在25~40，鲜茶汁PPO 活性能保持较高的活性当温度超过40 鲜茶汁 PPO 酶活性开始迅速下降pH 值为5.5~6.5 鲜茶汁PPO 活性较为稳定当pH 值超过6.5 PPO 活性开始迅速下降 不同浓度柠檬酸和NaHSO3对鲜茶汁中PPO 的活性均有一定的抑制效果其中0.5%的柠檬酸在室温下对多酚氧化 酶活性的抑制率可达85.01%。

Analysis on PPO activities and its influencing factors during the storage of fresh tea juice

Fresh tea juice is extremely prone to browning during its storage for high content of polyphenols. In this study, influences of different temperature, pH and inhibitors with different concentrations on the activities of polyphenol oxidase were analyzed by using the method of spectrophotometry. The results showed that activities of polyphenol oxidase in fresh tea juice maintained at high level within 25~40, activities of polyphenol oxidase in fresh tea juice dropped rapidly after its temperature exceeded 40. Activities of polyphenol oxidase in fresh tea juice were relatively stable when the pH was between 5.5 and 6.5, and decreased rapidly after pH exceeded 6.5. Citric acid and NaHSO3 with different concentrations could obviously inhibit the activities of polyphenol oxidase in fresh tea juice, and 0.5% citric acid had the best effect on inhibiting the activities of polyphenol oxidase in fresh tea juice.