冻融循环对甲壳素凝聚态结构和脱乙酰反应的影响

Effects of Freezing-thawing Cyclic Treatment on Condensed State Structure and N-deacetylation of Chitin

甲壳素和质量分数为40%的浓NaOH溶液的混合物在-18℃和40℃条件下反复进行冻融处理,结果表明慢速冷冻加低温解冻的冻融循环处理过程中,冰晶的反复形成和重结晶能够破坏甲壳素凝聚态特别是晶态结构。经过3次冻融循环处理,可使甲壳素在NaOH溶液中完全溶解,获得甲壳素最终质量分数为4%,NaOH最终质量分数约为10%的均相溶液,为用均相脱乙酰法制备半脱乙酰水溶性甲壳素提供前提。

The effects of freezing-thawing cyclic（FTC） treatment on the condensed state structure and Ndeacetylation 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-solublechitin.