Formation of Ca(II) and Zn(II) with chitosan and the study on GFC spectra of oligosaccharides by oxidizing degradation and their reactivity of scavenging active oxygen

Complexes of chitosan with Ca(Ⅱ) or Zn(Ⅱ) were prepared by adding CaAc_(2)·H_(2)O or ZnAc_(2)·2H_(2)O to chitosan solution.H_(2)O_(2) was used to degrade chitosan-Ca(Ⅱ) and Zn(Ⅱ) complex,the molecular weight and the molecular weight distribution of degraded products were investigated after eliminating Ca(Ⅱ) or Zn(Ⅱ) ions through the cation exchange resin.The results suggested that the chitosan could be degraded rapidly as the temperature raised;the degradation started from chitosan with higher molecular weight,the molecular weight distribution of oligosaccharides was narrow.The index of molecular weight distribution changed with the degree of degradation,the smaller the DP was,the smaller the index was.Moreover,the scavenging effect on the superoxide radical(O~(-·)_(2)) and the inhibitory effect on peroxides were also investigated.The results showed that both chitosan-(Ca(Ⅱ)) and chitosan-Zn(Ⅱ) exhibited scavenging effect.The smaller of DP,the higher of eliminated rate could be reached.However,when chitosan was degraded to glucosamine,the scavenging effect of metal coordination almost disappeared.