Polyphenol Oxidase Activity and Total Phenol Content in Red Wine Grape

Polyphenol oxidase(PPO) activity,total phenolic(TP) content and the browning degree(BD) of 27 cultivars of red wine grape and the influence of this three factors on the value of L* of wine were analyzed.Variety selection was carried out by system clustering using ratio η(PPO activity/TP content),and further divided using quadrant distribution between the average of the two indicators.The results showed significant differences in PPO activity,total phenolic content and browning degree among different red wine grape varieties.There was no significant correlation between the PPO activity and total phenol content,but they were both significantly positively related to the browning degree.PPO activity,total phenolic content and the browning degree were significantly negatively correlated with L* value of red wine.Cabernet Gernischet,Seibel Noir,Cabernet Sauvignon,Merlot,Kapц Maт and Cabernet Franc were selected as fine red wine grape varieties with low PPO activity and high total phenolic content.