Study on the heating-inactivation of PPO in apple during the processing of concentrated apple juice
The conditions of making polyphenoloxidase(PPO) of apple juice completely or partly inactivated and the inhibition on enzyme activity of treated apple juice in simulation system which was similar to the natural pH of apple juice were investigated. The results showed that activity of PPO was not completely but largely destroyed when the temperature was 75 ℃ and processing time was 30 s,and activity of PPO in treated apple juice could be inhibited by the low pH of 3.8 which was similar to the natural pH of apple juice. In that condition,the best effects were obtained.