ε-聚赖氨酸抗菌涂层制备及在淡水鱼保鲜中的应用

Preparation of Antibacterial Coating Containing ε-Polylysine and Its Application in Freshwater Fish Preservation

为延长淡水鱼常温保存货架期,本实验以ε-聚赖氨酸(ε-polylysine,ε-PL)、双(2-乙己基)磺基丁二酸钠(sodium bis(2-ethylhexyl) sulfosuccinate,AOT)为原料,通过一步静电组装技术制备ε-PL-AOT抗菌保鲜膜涂层,并对其分子结构、涂层稳定性和抗菌性能等进行研究;以草鱼鱼片为研究对象,初步评价了其保鲜效果。结果表明:在pH 2、ε-PL和AOT质量浓度分别为1.5 g/100 mL和3 g/100 mL条件下,可形成水不溶、乙醇可溶的稳定复合物ε-PL-AOT;质量分数2%的复合物乙醇溶液可以在保鲜膜表面形成稳定涂层,并对大肠杆菌和金黄色葡萄球菌均具有明显抗菌效果。应用实验结果显示,相比普通市售聚乙烯保鲜膜,ε-PL-AOT抗菌膜具有明显保鲜效果,处理的鱼肉在37 ℃条件下放置24 h后表面菌落总数低于1×10^(4)CFU/g,满足GB 4789.2-2016《食品安全国家标准 菌落总数测定》肉制品一级鲜度标准。本研究中ε-PL-AOT复合物涂层制备工艺简单、稳定性好、保鲜效果显著,具有工业化生产前景,为ε-PL在食品保鲜包装材料领域的产品开发提供了参考。

In order to prolong the shelf life of freshwater fish at room temperature,an antibacterial coating consisting ofε-polylysine(ε-PL)and sodium bis(2-ethylhexyl)sulfosuccinate(AOT)was prepared by one-step electrostatic assembly,and its molecular structure,stability and antibacterial properties were studied.The effect of the antibacterial coating on preserving the quality of grass carp fillets was evaluated as well.The results showed that a stableε-PL-AOT complex insoluble in water and soluble in ethanol was formed at pH 2,ε-PL concentration of 1.5 g/100 mL and AOT concentration of 3 g/100 mL.The complex at 2%in ethanol formed a stable coating on the surface of plastic wrap,which was effective against Escherichia coli and Staphylococcus aureus.The ε-PL-AOT antibacterial film had a higher antibacterial effect compared with ordinary commercial polyethylene(PE)film.After the ε-PL-AOT treated fish was kept at 37℃ for 24 h,the total number of bacterial colonies on the surface was 870 CFU/g,which meets the requirement of the Chinese national standard for the first freshness grade of meat products.Theε-PL-AOT composite coating has the advantages of simple preparation process,good stability and significant antibacterial effect and is promising for industrial production.The present study will hopefully promote the application ofε-PL-based coating in the preservation of freshwater fish products.