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摘要：本文研究了生姜精油、肉桂精油、丁香精油对大肠杆菌的抑菌活性，并选取抑菌性最好的精油作为抑菌剂来研究其对大肠杆菌抗性的影响。大肠杆菌在1/2MIC和1/4MIC的肉桂精油中暴露24小时后，对肉桂精油的直接保护和各种应力（高温50℃，乳酸pH4.5，氯化钠1g/10mL）下的间接保护进行了研究。主要实验结果如下（1）生姜精油、肉桂精油、丁香精油对大肠杆菌都有抑菌效果，但是其中肉桂精油的抑菌效果最为明显。其MIC为250μg/mL。（2）所有肉桂精油的实验浓度（MIC, 1/2MIC 和1/4 MIC）下，都抑制了大肠杆菌的生长。（3）大肠杆菌在亚致死浓度的肉桂精油中，直接保护和交叉保护对大肠杆菌抗性的影响没有明显变化。（4）在浓度递增的连续适应性培养实验中，肉桂精油对大肠杆菌抗性无明显影响。21044
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毕业论文关键词：肉桂精油、直接保护、交叉保护、大肠杆菌、抗性
Effect of plant essential oils against Escherichia coli resistance
Abstract:In this study, the antimicrobial effects of cinnanmon essential oil,clove essential oil, ginger essential oil on E. coli are evaluated. And select the best antimicrobial activity of essential oils as a bacteriostatic agent to study the effects of E.coil resistance. The induction of direct protection against cinnamon of cross protection against various stresses (high temperature 45℃；lactic acid, pH 4.5;NaCl 1g/10mL) after exposure to sublethal amounts of cinnamon was also evaluated. The main results are as follows:(1) cinnanmon oil、clove oil and garlie oil all decreased the cell viability of E. coli, cinnamon oil whose MIC is 250μg/mL is the best of them.(2) cinnanmon oil decreased the cell viability of E.coil in LB broth over 120min of exposure at all assayed concenteations (MIC,1/2MIC,1/4MIC).(3) Sublethal concentrations of E.coil in cinnamon oil, the direct protection and cross-protection did not change significantly impact resistant E.coil.(4) In increasing concentrations of continuous adaptive culture experiments, cinnamon oil had no significantly effect on E.coil resistance.
Key words:
Cinnanmon oil; direct protection; cross-protection; E. coli, resistance
目录
1引言 1
1.1 植物精油现状 2
1.1.1 植物精油的种类 2
1.1.2 植物精油的特点 3
1.2植物精油对细菌的抑制效应 4
1.3植物精油的抑菌实验现状 4
1.3.1牛至，迷迭香或大蒜精油的抑菌实验 4
1.3.2含佛手柑精油的壳聚糖的抑菌实验 4
1.3.3牛至或百里香精油的抑菌实验 5
1.3.4丁香、茴香等精油的抑菌实验 5
1.4食品保鲜方法研究进展 5
1.4.1涂膜保鲜 5
1.4.2可食性薄膜保鲜 6
1.5本课题的研究目的和意义 8
2实验材料和方法 9
2.1 实验材料 9
2.1.1植物精油 9
2.1.2菌种和培养基 9
2.1.3试剂 9
2.1.4主要仪器 10
2.2 实验方法 10
2.2.1精油的最低抑菌浓度（MIC）的测定 10
2.2.2动态杀菌曲线 10
2.2.3直接保护效应 10
2.2.4 间接保护效应 11
2.2.5连续的适应性培养 11
3结果与讨论 11
3.1植物精油的筛选 12
3.1.1精油对大肠杆菌的MIC的测定 12
3.1.2动态杀菌曲线 12
3.2直接保护效应 13
3.3间接保护效应 14