[en] The influence of electron beam irradiation on the activity and structure of PPO (Polyphenol oxidase) was analyzed. The results showed that electron beam irradiation can reduce PPO enzyme activity to a certain extent at a dose lower than 4.83 kGy. Analysis by circular dichroism (CD) showed that PPO protein's relative content of secondary structure affected by electron beam irradiation and total content of alpha helix, beta, and beta folding angle changed slightly. In contrast, at a dose higher than 4.83 kGy, the total content of the alpha helix, beta folding, and beta angle declined, and the random curl content increased. SDS-PAGE results showed that simultaneous cross-linking and degradation of the PPO enzyme occurred during irradiation. The experimental results indicate that electron beam irradiation can inhibit the activity of PPO. (author)