[关键词]
[摘要]
香辛料精油可以有效地抑制微生物生长,延缓食品腐败变质,但体内应用时其抑菌活性常受到食品成分的影响。本文以最低抑菌浓度(MIC)和抑菌圈直径(DIZ)为指标,发现肉桂、丁香、大蒜、生姜、百里香、鼠尾草、迷迭香、芥末和牛至9种香辛料精油中肉桂精油是对大肠杆菌和金黄色葡萄球菌抑菌活性均最高的精油,MIC分别为250 μL/L和500 μL/L,DIZ分别为31.8±1.7 mm和30.5±0.5 mm。通过Modified Gompertz生长模型,研究肉桂精油在蛋白质和碳水化合物两类食品模型中对两种受试细菌延滞期(λ)和最大比生长速率(μmax)的影响。结果显示:蛋白质和碳水化合物对肉桂精油抑菌活性均有加强作用;大肠杆菌在牛肉和马铃薯模型(含有1/4MIC肉桂精油)中的λ较Luria-Bertani培养基分别延长1.76倍和2.51倍;同样模型中,金黄色葡萄球菌在24 h内生长完全受到抑制。上述结果表明肉桂精油具有在蛋白质或碳水化合物成分高的食品中推广应用的潜力。
[Key word]
[Abstract]
Essential oils from spices can effectively inhibit the growth of microorganisms and delay food spoilage; however, the antimicrobial activities of spice oils are often affected by food ingredients, during in vivo application. In this study, minimum inhibitory concentration (MIC) and diameter of inhibition zone (DIZ) were used as the indices. Cinnamon, clove, garlic, ginger, thyme, sage, rosemary, mustard, and oregano oil were used as the study objects, and cinnamon oil was found to have the strongest antibacterial activity against Escherichia coli and Staphylococcus aureus. The corresponding MIC values were 250 μL/L and 500 μL/L, respectively; the corresponding DIZ values were 31.8 ± 1.7 mm and 30.5 ± 0.5 mm, respectively. The modified Gompertz model for bacterial growth was employed to study the effects of cinnamon oil on the lag phase (λ) and the maximum specific growth rate (μmax) of the two test bacteria in the protein- and carbohydrate-based model foods.. The results showed that proteins and carbohydrates exhibited a strengthening effect on the antibacterial activity of cinnamon oil. At 1/4 MIC of cinnamon oil, the lag phases of E. coli were increased by 1.76 fold and 2.51 fold in beef broth and potato broth compared to that in Luria-Bertani broth, respectively. In the same models, the growth of S. aureus was completely inhibited. The above results suggest that cinnamon oil has the potential to be widely applied in foods containing a high level of protein or carbohydrate.
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[基金项目]
上海市部分地方院校能力建设计划项目(13120503300)