Abstract: The effects of mechanical damage on physiological changes and the enzymatic activity of Fuji apples during storage at 5℃ and 18℃were investigated. The results showed that the relative electrical conductivity increases rapidly, L* value decreases rapidly, the content of polyphenol decreased gradually, the content of malondialdehyde(MDA)increases gradually and flesh becomes brown rapidly in Fuji apples after mechanical damage. The activities of polyphenol oxidase(PPO) and peroxidase(POD) and catalase (CAT) all increase while the activity of superoxide dismutase (SOD) is restricted after mechanical damage. The parameters show the increasing and reducing cycles except PPO after extension of storage. It also showed that the protective enzyme system of injured tissue defends stress and the better activity of enzyme delays aging of fruit during low temperature storage.

Key words: mechanical damage, Fuji apple, polyphenol oxidase, enzymatic browning