羧甲基丝素的制备工艺优化及其乳化性能

以废丝为主要原料,将不溶于水的丝素蛋白通过与一氯乙酸在乙醇溶剂中的醚化反应,合成了可溶性的羧甲基丝素。讨论了几种主要因素(如碱化时间、碱化温度、醚化时间和醚化温度等)对产物醚化度的影响,得到了制备羧甲基丝素的醚化工艺条件:碱化时间90 min、醚化时间90 min、碱化温度25℃、醚化温度70℃。所得羧甲基丝素的醚化度为0.7425。测定羧甲基丝素的表面活性后,得到羧甲基丝素的临界胶束浓度为1.25 g/L,亲水亲油平衡(HLB)值为10。丝素蛋白溶液具有一定的起泡能力,且在质量分数为1.0%～1.2%范围内的稳定性较好,但不宜作发泡剂。丝素蛋白溶液具有良好的乳化能力和乳化稳定性,可作为良好的乳化剂。

Optimized Preparation and Emulsifying Properties of Carboxymethyl Silk Fibroin

Soluble carboxymethyl silk fibroin was prepared from the waste silk by etherification of the water-fast silk fibroin and the monochloracetic acid in ethanol. Various factors on etherified degree of products(such as alkalized time, alkalized temperature, etherified time and etherified temperature, etc.) were discussed. The optimized etherification conditions for preparing the carboxymethyl silk fibroin are: alkalization time:90 min; etherification time:90 min; alkalization temperature:25 ℃, etherification temperature:70 ℃. The degree of etherification of the carboxymethyl silk fibroin is 0.7425. The critical micellar density of carboxymethyl silk fibroin is 1.25 g/L and the hydrophilic-lipophilic balance(HLB) value is 10. The fibroin solution is unsuitable for using as a foamer, even though it has some foaming ability, and the formed foam is stable in the mass ration range of 1.0%~1.2%. The silk fibroin solution has exhibited excellent emulsifying capacity and emulsion stability, which renders the silk fibroin can be used as good emulsifiers.