High Pressure Homogenization In The Degradation Of Applied Research,

In order to prepare low-molecular-weight chitosan in physical way, this dissertation is intended to study on the application of high pressure homogenization technique in the degradation of chitosan. Two methods, one is high pressure homogenization, the other is the combination of high pressure homogenization and hydrogen peroxide (H₂O₂), were adopted to degrade chitosan. The influence of some factors, such as concentration, pressure and temperature was investigated, and the performance and structure of products were discussed. The main content and results are showed as follows:(1)Chitosan was degraded by high pressure homogenization, and its effect increased with molecular weight of original chitosan, pressure and number of cycles, decreased with the concentration of chitosan, while both the concentration of acetic acid (HAc) or sodium acetate (NaAc) and temperature had a negligible influence. What's more, theoretical model was built and the mechanism of homogenizer was discussed.(2)Chitosan was: degraded by the combination of high pressure homogenization and H₂O₂, and its effect increased with the concentration of H₂O₂, pressure, temperature and number of cycles, decreased with the concentration of chitosan, while exhibited an increase-to-decrease trend with the concentration of HAc.(3)The degradation of chitonsan by both high pressure homogenization and the combination of high pressure homogenization and H₂O₂, didn't destroy basic functional groups and structure unit of chitosan, indicating that most of fragmentation happened onβ-(1,4) indican bond.(4)The effect of the combination of high pressure homogenization and H₂O₂ was better than the adoption of only one of them, indicating that high pressure homogenization technique hastened the degradation of chitosan by the oxidation of H₂O₂, while keeping its own effect.