新型壳聚糖基水果保鲜剂的制备

Synthesis of new chitosan based fruit fresh keeping agents

基于壳聚糖良好的成膜、保水性,结合半胱氨酸的抗氧化、抑菌性和N-乙烯基吡咯烷酮的亲水性,制备了壳聚糖-乙烯基吡咯烷酮-半胱氨酸接枝共聚物(CTS-g-PVP-cys)。采用抑菌圈法研究了CTS-g-PVP-cys对大肠杆菌、金黄色葡萄球菌和蜡样芽孢杆菌的抑菌效果。结果表明:当共聚物中巯基含量为266μmol/g时,CTS-gPVP-cys对大肠杆菌、金黄色葡萄球菌均有较好抑菌效果,最大抑菌率分别为87.50%,89.33%,即CTS-g-PVP-cys很大程度上协同了半胱氨酸的抑菌性。同时,CTS-g-PVP-cys涂膜可降低水果中营养物质及水分的损失,具有防褐变效果,可作为良好的保鲜剂。

Chitosan-poly（N-vinylpyrrolidone）-cysteine graft copolymer（CTS-g-PVP-cys） was prepared thanks to the excellent film-forming and the water retention of CTS,antioxidant and antimicrobial activities of L-cys and hydrophilic properties of PVP. The inhibitory effects of CTS-g-PVP-cys on Escherichia coli,Bacillus cereus and Staphylococcus aureus were observed via the method of inhibition zone. The experimental results indicate that：when the content of thiol in copolymer is 266 μmol/g,CTS-g-PVP-cys exerts good antimicrobial effect on Escherichia coli and Staphylococcus aureus and the maximum inhibition rate are 87.50% and 89.33% respectively,that is,the copolymer has coordinated substantially the antimicrobial activity of cys. CTS-g-PVP-cys films can also reduce the losses of nutrients and water in fruits,it can be used as a good fresh keeping agent for fruits anti-browning.