Active packaging incorporating antioxidants and antimicrobials is creating a niche in the market and becoming increasingly important. The main goal of this work was the design of bioactive bilayer films (zein/pullulan) incorporating licorice essential oil. The bilayer films were fully characterized in terms of their chemical, physical, barrier, antioxidant, and antimicrobial properties. Furthermore, the release kinetics of isopropyl palmitate, the major compound of the licorice essential oil, was evaluated by HPLC-DAD (high-performance liquid chromatography coupled to diode-array detector). Scanning Electron Microscopy (SEM) micrographs of cross-sections of the bilayer films clearly show the two layers of the films. Besides presenting the capacity to scavenge free radicals and to inhibit the lipid peroxidation, the developed bilayer films were also able to inhibit the growth of known foodborne pathogens (Enterococcus faecalis and Listeria monocytogenes). The release kinetics profile of isopropyl palmitate from bilayer films incorporating licorice essential oil demonstrated that in 50% ethanol at room temperature, the release was more effective, suggesting that the bilayer films will be more efficient if applied to package semi-fatty food.

中文翻译：

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生物活性双层薄膜的设计和表征：棕榈酸异丙酯的释放动力学。

包含抗氧化剂和抗菌剂的活性包装正在市场中占据一席之地，并且变得越来越重要。这项工作的主要目的是设计包含甘草精油的生物活性双层薄膜（玉米蛋白/普鲁兰多糖）。双层膜的化学，物理，阻隔性，抗氧化剂和抗菌性能均得到了充分表征。此外，通过HPLC-DAD（与二极管阵列检测器耦合的高效液相色谱法）评估了甘草精油的主要化合物棕榈酸异丙酯的释放动力学。双层薄膜横截面的扫描电子显微镜（SEM）显微照片清楚地显示了薄膜的两层。除了具有清除自由基和抑制脂质过氧化的能力外，粪肠球菌和单核细胞增生李斯特菌（）掺有甘草精油的双层薄膜中棕榈酸异丙酯的释放动力学曲线表明，在室温下于50％的乙醇中，该释放更为有效，这表明该双层薄膜如果用于包装半脂肪食品，将更加有效。