摘要：本文以苦荞麦为原料，利用乙醇提取和超声波辅助提取的方法对苦荞麦中的黄酮类化合物进行了提取，研究确定其提取的最佳工艺，并以黄酮类化合物的得率为指标。通过单因素实验和正交实验对两种提取过程的工艺条件进行了优化。并在最优的提取条件下，利用滤纸片扩散法比较了两种提取方法对苦荞麦中黄酮类化合物对于大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌的抑菌效果。57936

结果表明：

1.乙醇提取法的最优提取工艺条件为：乙醇提取时间8小时、提取温度70℃、乙醇质量分数80%。其得率为：1.8902%。

2.超声波辅助乙醇提取的最优提取工艺条件为：乙醇质量分数80%，提取温度50℃，提取时间30分钟，提取功率420W。其得率为2.547%。

3.抑菌结果表明：

（1）超声辅助乙醇提取的抑菌效果比乙醇提取法的抑菌效果好。

（2）超声波辅助乙醇提取的产物对于大肠杆菌的最小抑菌浓度（MIC）为5mg/ml,

对于金黄色葡萄球菌与枯草芽孢杆菌的最小抑菌浓度（MIC）同样为10mg/ml。

毕业论文关键词：  苦荞；黄酮化合物；超声波；提取；抑菌性

Ultrasonic assisted the extraction of flavonoid and the anti-microbial properties of the flavonoid

Abstract: This research used bitter buckwheat as the raw material of the extraction of flavonoid and use ethanol to extract the flavonoid from the bitter buckwheat. The research has determined the optimum process of extracting. The content of total flavonoids were investigated through spectrophotography with rutin as a reference substance. Use ultrasonic assisted ethanol to extract the flavonoid, the influence of the flavonoids extraction yield with assisted by ultrasonic were studied by orthogonal design and also obtained the optimal technology parameter. The antimicrobial activity changes caused by different content of flavonoid were studied by filter paper dispersion methods.

The main results were as follows:

1. This research obtained the technological parameters and optimal process conditions. The variables considered were time, volume percentage of ethanol, temperature and ultrasonic power in the experiment design. Based on the single experiment results, the optimum conditions were as follows: ultrasonic power, 420W, temperature, 50℃, volume percentage of ethanol, 80%, time, 30min. And under the above conditions, the flavonoids extraction yield could reach the highest, 2.547%.

2. The biggest factor of the technology parameter of the extraction of the flavonoid from the buckwheat could be known through analysis: when the volume percentage of ethanol is 80%, the extraction yield could reached the maximal. With the assisted by ultrasonic, when the ultrasonic power is 420W, the extraction yield could reached the maximal.

3. The antimicrobial activity of flavonoid was determined by filter paper dispersion method and the result were as follows:

(1) The inhibition effect of extraction with the assisted by ultrasonic was better.

(2) The experiment of minimum inhibitory concentration (MIC) on E.coli was 5mg/ml, while the MIC on staphylococcus aureus and bacillus subtills was 10mg/ml.

KeyWords:  Buckwheat; Flavonoid; Ultrasonic; Extract; Antimicrobial Activity

 目录

1 绪论 1

1.1苦荞麦概述 1

1.1.1 苦荞中黄酮类化合物生物活性 1

1.1.3 黄酮类化合物的物理性质 3

1.1.4 苦荞中其他化学成分及价值