壳聚糖山梨酸酯的合成、表征及抑菌活性研究

摘要

通过2步反应合成了壳聚糖山梨酸酯.第1步,山梨酸在氯化亚砜中回流制备山梨酰氯;第2步,壳聚糖与山梨酰氯在甲烷磺酸的催化下酯化合成了壳聚糖山梨酸酯衍生物.采用红外光谱(FT-IR)和核磁共振氢谱(1H NMR)对衍生物的结构进行了表征.结果表明,壳聚糖的羟基与山梨酰氯发生了取代反应,其氨基仍以游离形式存在.在不同的反应物比例下,制备了取代度(DS)分别为0.44、1.21、1.93的3种衍生物,抑菌实验的结果显示:取代度为1.21的壳聚糖山梨酸酯对大肠杆菌、金黄色葡萄球菌和黑曲霉抑制作用最强,最小抑菌浓度分别为0.125,0.125和0.5 g/L.壳聚糖山梨酸酯的抑菌活性远高于壳聚糖,具备作为防腐剂在食品中应用的基础.%An efficient procedure to prepare chitosan sorbate was established by using one two-step reaction.Firstly, sorbyl chloride was prepared by reflux of sorbic acid in thionyl chloride.Secondly, chitosan was selectively esterified with sorbyl chloride in MeSO3H.The chemical structure of the chitosan derivative was characterized by FTIR and 1 H-NMR analysis.The results showed sorbyl chloride mainly substituted with the hydroxyl group rather than amino group of chitsoan.The derivatives with DS of 0.44,1.21,1.93 were prepared with different molar ratio of chitosan and sorbyl chloride.The derivative ( DS = 1.21 ) manifested the strongest antimicrobial activity with the MIC of 0.125％ , 0.125％ and 0.5 (w/v) against Escherichia coli, Staphylococcus aureus and Aspergillus niger.