【摘要】 具有低温溶解、软凝胶特性的琼脂,属特种性能海藻胶体。以市售琼脂为原料,采用螺杆挤压预处理;在单因素试验基础上,运用响应面法优化羧甲基化工艺,制备低温溶解的软凝胶琼脂。优化的工艺参数为:氯乙酸钠添加量0.027 mol、羧甲基化反应温度53.0℃、乙醇浓度74.0%,在此条件下制备改性琼脂的溶解温度为55.4℃、凝胶强度为58.6 g/cm~2;核磁共振分析表明羧甲基官能团被引入到琼脂的糖单元结构中,但原有结构未破坏;扫描电镜图像表明琼脂颗粒一定程度破坏,使得比表面积增大。更多还原

【Abstract】 The agar with low solution temperature and soft gel properties is a special alga colloid. In this study,commercial agar was use as material. It was pre-treated by screw extrusion. Based on single factor experiments,the parameters of carboxymethylation were optimized by using response surface methodology to prepare modified agar. The optimized reaction conditions were 0.027 mol of sodium chloroacetate, 53.0 ℃ of reaction temperature,and 74.0 % of ethanol concentration. Under the conditions,modified agar had a solution temperature of 55.4 ℃ and gel strength of 58.6 g/cm~2. Nuclear magnetic resonance(NMR)analysis showed that carboxymethyl functional group was introduced into gel structure and original structure was not destroyed. The images of scanning electron microscope exhibited that agar particles were destroyed which could increase specific surface area.更多还原