Degradation of chitosan in solution by gamma irradiation in the presence of hydrogen peroxide

Chitosan from squid pens with deacetylation degree (DD) of 70% and average molecular weight (Mw0) 90.5 × 103 in dilute lactic acid solution containing H2O2 (1%) was effectively degraded by irradiation with gamma 60Co radiation (1.33 kGy/h) at doses in the range 4–16 kGy. Based on the results of Mw measured by gel permeation chromatography (GPC), it was concluded that there was particularly strong synergy between H2O2 and radiation for degradation at the lower radiation doses studied. Radiation scission yields (Gs) were found out to be 2.2 μmol/J and 0.2 μmol/J for 5% chitosan with and without 1% H2O2, respectively. The DD of degraded chitosan measured from IR spectra was almost unchanged by the treatment.