The objective of this study was to utilize self-assembly properties of sodium caseinate to prepare nanoemulsions after neutralization of alkaline mixtures with 2% w/v caseinate and up to 3% v/v thyme oil. The encapsulation efficiency was >90% at a surfactant-to-oil ratio of up to 1:1.25. The nanoemulsions had structures smaller than 75 nm according to atomic force microscopy and stable hydrodynamic diameters of ~90-200 nm during 20-day storage at room temperature. When tested against Escherichia coli O157:H7 ATCC 43895 and Staphylococcus aureus ATCC 25923 in tryptic soy broth and milk, the encapsulated thyme oil was more active than free thyme oil. Additionally, S. aureus was more resistant than E. coli O157:H7, requiring 11.7 and 5 g/L of encapsulated thyme oil, respectively, to completely deactivate bacteria in milk in 4 h. The findings suggest that thyme oil nanoemulsions can be potentially used as natural preservatives to improve food safety.

中文翻译：

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由碱性百里香油和酪蛋白酸钠混合物自组装而成的中性纳米乳剂的物理和抗菌性能。

这项研究的目的是利用酪蛋白酸钠的自组装特性，在将碱性混合物与2％w / v酪蛋白酸盐和高达3％v / v百里香油中和后，制备纳米乳剂。在表面活性剂与油的比例最高为1：1.25的情况下，包封效率> 90％。根据原子力显微镜，纳米乳剂具有小于75nm的结构，并且在室温下储存20天期间稳定的〜90-200nm的流体动力学直径。在胰蛋白酶大豆肉汤和牛奶中针对大肠杆菌O157：H7 ATCC 43895和金黄色葡萄球菌ATCC 25923进行测试时，封装的百里香油比游离百里香油更具活性。此外，金黄色葡萄球菌比大肠杆菌O157：H7更具抗性，分别需要11.7和5 g / L的封装百里香精油才能在4小时内完全灭活牛奶中的细菌。