Abstract: The effects of electric field strength, reaction time, chitosan concentration and solution conductivity on the degradation rate of chitosan were studied by pulsed electric field (PEF) treatment. The results showed that the molecular weight of chitosan revealed a decrease trend with increasing electric field strength, and a significant degradation was observed at high electric field strength. The degradation rate increased up to 54.2% after PEF treatment at 33.3 kV/cm; the degradation rate revealed a reduction with prolonged reaction time by 18.5% and 8.5% over the first 20 min and the last 70 min, respectively. Increasing solution concentration or conductivity was unfavorable for the degradation of chitosan. Infrared spectral analysis indicated that the structure of chitosan was not changed during degradation. The X-ray diffraction patterns of original chitosan and degraded chitosan exhibited a similar structure with characteristic peaks at 2θ of 10.4° and 20.2°, suggesting that degraded chitosan maintains its crystal structure.

Key words: chitosan, PEF, relative molecular weight, degradation