Mechanism of Enzymatic Browning of Hosui Pear during Low Temperature Storage

The polyphenol oxidase(PPO) activity,peroxidase(POD) activity,total phenolic content and malonaldehyde(MDA) content in different tissues of Hosui pear were determined at 30 d,60 d,90 d,120 d and 150 d of low temperature storage.Results showed that the browning indice of fruit peel and fruit core of Hosui pear were below 4% during 30-120 d storage,and the difference between them was not significant.During 120-150 d,the browning indice of fruit peel and fruit core increased obviously,and the browning index,polyphenol oxidase activity and malonaldehyde content of fruit core were significantly higher than those of fruit peel,however,the peroxidase activity and total phenolic content of fruit core were significantly lower than those of fruit peel.Fruit flesh had no browning symptom during the whole storage(0-150 d).