Effect of ultrasonic processing on the properties of polyphenol oxidase from potato (Solanum tuberosum L.)

Abstract

In present work, the effects of ultrasound on activity and conformation of polyphenol oxidase (PPO) from potato were investigated under different ultrasonic gradient for ultrasonic power (240-600 W), time (15-120 min), temperature (20-50℃) and pH (5.4-8.2). The results indicated that potato PPO exhibited a decrease in activity treated by different ultrasonic treatment conditions. Furthermore, the ultrasound significantly down-regulated the expression of PPO gene. The CD analysis demonstrated that the secondary structures such as α-helix were destroyed compared with the pristine PPO. The PPO activity showed a corresponding decrease along with the changes in the secondary structure. This investigation revealed that ultrasound inactivate PPO activity by changing the conformation of enzyme protein and down-regulating gene expression.