壳聚糖-丁香精油微乳液复合膜的制备及其对猪肉的保鲜作用

Preparation and pork preservation application of chitosan films incorporated with clove essential oil microemulsions

目的 探究壳聚糖-丁香精油(clove essential oil, CEO)微乳液复合膜对猪肉的保鲜效果。方法 首先将丁香精油运载到微乳液中,然后制备壳聚糖-丁香精油微乳液复合膜,并探索复合膜的理化特征及其对猪肉的保鲜作用。结果 丁香精油微乳液对大肠杆菌和金黄色葡萄球菌的最低抑菌浓度(minimum inhibitory concentration, MIC)均为62.5μL/L,而纯丁香精油对这两种菌的MICs分别为500和125μL/L,说明微乳液技术提高了丁香精油的抑菌效果。随着添加到壳聚糖薄膜中的微乳液浓度增加(0、0.5%、1.0%、3.0%),复合膜的厚度、不透明度和色差均不断增加,而水分活度却逐渐降低。其中,复合膜的水分活度(0.486~0.536)低于允许微生物生长的最低水分活度(0.610),说明其适合作为抑菌包装材料。此外,猪肉保鲜试验结果显示,壳聚糖-丁香精油微乳液复合膜可以有效抑制猪肉冷藏期间总菌数的增长,同时较好地延缓猪肉的脂质氧化。结论 本研究制备的复合膜理化特征较好,可用于猪肉的防腐保鲜,为丁香精油在肉制品保鲜领域的应用奠定了基础。

Objective To explore the effects of chitosan films incorporated with clove essential oil(CEO)microemulsions on pork preservation. Methods CEO was loaded in a microemulsion system, and this microemulsion was then incorporated into chitosan films. The resulting films were subjected to physiochemical property analysis and pork packaging application. Results CEO microemulsions exhibited a minimum inhibitory concentration(MIC) of 62.5 μL/L against both Escherichia coli and Staphylococcus aureus. However, the MICs of pure CEO against these 2bacteria were 500 and 125 μL/L, respectively, indicating that the antibacterial activity of CEO could be enhanced by microemulsion technology. When different concentrations of CEO microemulsions(0, 0.5%, 1.0%, 3.0%) were added into chitosan films, film thickness, opacity, and total color difference were enhanced, while film water activity was reduced. Interestingly, water activity of all composite films(0.486-0.536) was lower than the minimum limit(0.610)required for microbial growth, which provided evidences for the suitability of chitosan-CEO microemulsion films for food packaging. In the pork preservation assay, chitosan-CEO microemulsion films were able to retard total viable count growth as well as lipid oxidation. Conclusion Composite films generated in this work have good physiochemical properties with the potential to extend the shelf life of pork, which offers a possible solution for the practical application of CEO in meat preservation.