过氧化氢甲壳素脱色反应条件与分子量研究

Study on Reaction Conditions and Molecular Weight in Bleaching of Chitin by Hydrogen Peroxide

研究了不同条件下过氧化氢对虾壳甲壳素脱色的影响 .实验结果表明 ,脱色反应速率在pH为 10 .5时达到最大 .升高温度、增加过氧化氢浓度加快脱色的进行 ,甲壳素脱乙酰后脱色时间大大缩短 ,为之前的 1/ 2 .过氧化氢脱色降低了产物的分子量 ,并且产物分子量随脱色温度的升高而降低 ,借此可以通过改变脱色条件来控制产物分子量 .虾壳甲壳素在 4 0℃ ,pH为 10 .5 ,c(H2 O2 )为 3%时反应 4 7min即可脱色 ,收率为 96 .2 % ;壳聚糖在此条件下用过氧化氢脱色后分子量为脱色前的 5 9% .

The influences of hydrogen peroxide on bleaching of shrimp chitin under different reaction conditions were systematically studied. Molecular weight and structures were characterized by gel permeation chromatography (GPC) and infrared spectrum (IR) respectively. The results indicated that the optimum pH was 10.5. High temperature, increased concentration of H 2 O 2 and deacetylation speeded the bleaching reaction. Molecular weight of product bleached by hydrogen peroxide decreased, lower at higher temperature, and could be controlled by changing reaction conditions. Shrimp chitin could be bleached within 47 min at 40℃, pH 10.5 by 3% H 2 O 2 , while molecular weight of chitosan remained 59% under the same conditions. IR spectrum confirmed the structure of chitin was not changed.