Abstract The present research was aimed to investigate the potentialities of ultra high pressure homogenization (UHPH) to produce stable natural antimicrobial based nanoemulsions. Initially, the nanoemulsions were characterized for their size, stability over time and antimicrobial properties against several pathogenic and spoilage microorganisms. After that nanoemulsions were tested to increase the safety and shelf-life of apple juice deliberately inoculated with pathogenic (Listeria monocytogenes Scott A, Staph. aureus SR231, Escherichia coli 555) and spoilage microorganisms (Saccharomyces cerevisiae SPA, Lactobacillus plantarum 82) and treated with different high pressure homogenization treatments. The analyses performed by dynamic laser light scattering showed that the hexanal and trans-2-hexenal based nanoemulsions were characterized by an average size of 86 and 100 nm, respectively while they were characterized by a stability, over time, of 14 months without separation. Moreover, the nanoemulsions resulted, after the UHPH treatment, colourless. The pathogenic species deliberately inoculated in apple juice decreased their cell loads with different kinetics in relation to the use of hexanal and trans-2-hexenal and high pressure homogenization treatment applied. Regarding spoilage microorganisms, S. cerevisiae cell loads decreased under detection limit (1 log CFU/mL) in juice containing nanoemulsions and treated at 200 MPa for 2 cycles. The data of the present research contribute to support the application of natural antimicrobial based nanoemulsions into complex food system, enlarging the experimental evidence for their use in food sector. In particular, the obtained hexanal and tran-2-hexenal based nanoemulsions have demonstrated great application, due also to their organoleptic compatibility, to the fruit juice sector, promoting also an increase of quality of apple juice.

中文翻译：

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结合使用天然抗菌纳米乳液和超高压均质提高苹果汁的安全性和保质期

摘要 本研究旨在研究超高压均质化 (UHPH) 生产稳定的天然抗菌纳米乳液的潜力。最初，纳米乳剂的特征在于它们的大小、随时间推移的稳定性以及对几种病原微生物和腐败微生物的抗菌特性。之后测试纳米乳液以增加故意接种致病微生物（单核细胞增生李斯特菌 Scott A、金黄色葡萄球菌 SR231、大肠杆菌 555）和腐败微生物（酿酒酵母 SPA、植物乳杆菌 82）并用植物乳杆菌处理的苹果汁的安全性和保质期不同的高压均质处理。通过动态激光散射进行的分析表明，基于己醛和反式 2-己烯醛的纳米乳剂的平均粒径分别为 86 和 100 nm，而它们的特点是随着时间的推移具有 14 个月的稳定性而不会分离。此外，纳米乳液在 UHPH 处理后是无色的。与使用己醛和反式 2-己烯醛以及应用的高压均质处理相关的，故意接种在苹果汁中的病原菌以不同的动力学降低了它们的细胞负荷。关于腐败微生物，在含有纳米乳液的汁液中，酿酒酵母细胞载量在检测极限 (1 log CFU/mL) 下下降，并在 200 MPa 下处理 2 个循环。本研究的数据有助于支持基于天然抗菌的纳米乳液在复杂食品系统中的应用，扩大了它们在食品领域使用的实验证据。特别是，获得的基于己醛和反式 2-己烯的纳米乳剂由于其感官相容性而在果汁领域具有很大的应用价值，也促进了苹果汁质量的提高。