用GC-MS对薄荷精油成分进行定量分析，通过拟三元相图，研究乙醇、正丙醇和正丁醇分别作为助表面活性剂时，对薄荷精油-吐温80-水食品级微乳体系相行为的影响。实验测定微乳液的密度、粒径、pH值等理化指标，其在NYDB培养基和不同饮料中对酿酒酵母菌的抑菌活性，通过大肠杆菌细胞膜通透性试验初步探究微乳液对细菌的抑菌机理。结果显示：薄荷精油主要成分为薄荷醇（30.67%）、薄荷酮（26.89%）等等。乙醇作为助表面活性剂增溶效果最好。配方ME1（精油:乙醇=1:1）和ME2（精油:乙醇=1:3）平均粒径分别为66.57 nm和55.63 nm。ME1的抑菌活性较强，在苹果清汁中对酿酒酵母菌的抑制效果最佳，28 ℃培养48 h MIC为64 μL/mL。5倍稀释ME1 37 oC培养75 min时大肠杆菌核酸泄漏率为51.68%。微乳液能通过增加大肠杆菌细胞膜通透性，使大肠杆菌由于释放核酸而死亡。

The composition of peppermint essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS). Using pseudo-ternary phase diagrams, the effect of various cosurfactants (ethanol, n-propanol, and n-butanol) on the phase behavior of the food-grade microemulsion system for peppermint essential oil using Tween 80-water was studied. In this study, the density, particle size, and pH value of the microemulsion, as well as its antimicrobial activity against Saccharomyces cerevisiae in NYDB medium and various drinks, were determined. The mechanism of the antimicrobial action of the microemulsion against Escherichia coli was primarily evaluated based on a cell membrane permeability assay. The results showed that the major components of peppermint essential oil were menthol (30.67%), and menthone (26.89%). Ethanol had the best solubilizing effect as a cosurfactant. The average particle sizes for two formulations (ME1, oil/ethanol = 1:1 and ME2, oil/ethanol = 1:3) were 66.57 nm and 55.63 nm, respectively. ME1 had higher antimicrobial activity and a better suppression effect against S. cerevisiae in clear apple juice. The minimum bactericidal concentration (MBC) was 64 μL/mL after cultures were grown at 28 ℃ for 48 h. When culturing with 5-fold diluted ME1 at 37 ℃ for 75 min, the leakage of E. coli nucleic acids was 51.68%. The microemulsion solution could kill E. coli by releasing nucleic acids and increasing the permeability of the E. coli cell membrane.

上海市教育委员会科研创新项目（12YZ165），上海市科学技术委员会项目（13120503300）