Enzymatic browning of banana during low temperature storage
1991
Jiang Yueming | Chen Mianda | Lin Zhifang (Academia Sinica, Guangzhou (China). South China Inst. of Botany)
The degree of banana browning during low temperature storage could be expressed as light absorbance at 450 nm. The absorbance of severely browned peel was twice as high as green-yellow peel. During the period of experiment, the glutathione content in banana peel stored at 7 C degrees decreased more rapidly than that stored at 24 C degrees, whereas the ascorbic acid content at 24 C degrees increased, but that at 7 C degrees decreased. Dopamine content increased within four day and then decreased. Furthermore, it was found that the rapid decrease of ascorbic acid, glutathione and dopamine contents was all correlated with the visible browning and the increase of OD450. The activities of PPO (polyphenol oxidase) POD (peroxidase) and CAT (catalase) were higher after storage at 24 C degrees than at 7 degrees. POD activity increased with the time of storage at both temperatures, but the changes in PPO and CAT activities showed different enzyme patterns. Analysis of the two forms (free and membrane bound) of PPO and POD indicated that low temperature storage could result in higher acitivity of enzyme in free form. It was shown that browning was delayed by treatment with n-propyl gallate, and promoted by H2O2. The above data of PPO, POD and CAT activities also provided evidence that the browning of banana was related to the oxidation and peroxidation of membrane and some substrates concerned
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