Abstract:The effects of freezing-thawing cyclic (FTC) treatment on the condensed state structure and N-deacetylation of chitin were investigated. The mixture of chitin and concentrated NaOH solutions (40%) was frozen at -18℃ and thawed at 40℃, repeatedly. Slowly freezing and low temperature thawing cycle process can thoroughly destruct the condensed state structure, especially the crystalline state structure, as a result of the ice crystals’ repeatedly formed and recrystallizated. Furthermore, via three times FTC treatment at -18℃, chitin was completely dissolved in NaOH aqueous solution and the homogeneous solution with a chitin concentration about 4% and a final NaOH concentration of approximately 10% formed, which is likely applied to prepare partial N-deacetylated water-soluble-chitin.