• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.392-396
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• 1995

Chitosan was prepared from red snow crab (Chinonecetes japonicus) under various conditions of deacetylation (NaOH concentration, heating temperature, heating time and intermittent and repetition treatment). By measuring the degree of deacetylation and the molecular weight (Mw), effect of preparation condition was studied. As the concentration of NaOH increased in deacetylation process, for chitosan treated over $40\%$ NaOH, the rate of increase of the deacetylation of chitosan decreased, but the difference of Mw decrease was nearly constant. When treatment temperature increased from $130^{\circ}C$ to $150^{\circ}C$, the deacetylation degree increased only $3^{\circ}C\;from\;84\%\;to\;87\%,$ but Mw decreased from 267,000 to 85,800. The difference of Mw decrease of chitosan treated $130-150^{\circ}C$ was larger than that with $90-130^{\circ}C$. The deacetylation degree and Mw of the chitosan prepared by continuous treatment for 3 hrs was$84\%$ and 267,000. On the other hand those of chitosan with intermittent and repetition treatment for 3hrs was $93\%$ and 28,000. In order to increase the degree of deacetylation and inhibit depolymerizing, the intermittent and repetition treatment was found to be more effective than the continuous treatment.