Study on the pear flesh browning and related physiology during pure oxygen storage.

Pears were stored in air(control) and 100%O_2 for up to 30 days in the conditions of 2℃and 95%relative humidity,and their quality changes were analyzed in terms of browning index,polyphenol oxidase(PPO),total phenolic content,pH value,color,moisture,ascorbic acid and soluble solids.The results showed that the browning index and pH value of all samples increased with storage time,but their brightness and ascorbic acid content decreased.The pure O_2-stored fruits were less in PPO activity and browning degree,but greater in total phenolic content and moisture contents as well as L and h values than the air-stored fruits.The browning index had a very significant positive correlation with the PPO activity, a high correlation with the ascorbic acid and moisture content,a moderate correlation with the ascorbic acid,pH and L value,and a significant negative correlation with the total phenolic content,but not a significant correlation with the soluble solids content and h value.