金银花中绿原酸的提取及检测_乌兰.

下,随着球磨时间的增加,其剪切应力显著下降。

用幂方程τ=k γm (其中k 为稠度系数;m 为流动特征指数对曲线进行拟合,结果如表2所示。

由拟合结果可知,在不同温度下,相关系数R 2在0.9850~0.9993之间,这说明方程与曲线有较好的相关性。同一样品的稠度系数k 随着温度的升高而减小,说明温度升高可以减小体系的稠度,增强淀粉糊的流动性。在同一温度下随着球磨时间的增加,稠度系数k 显著下降,流动指数m 则是呈现增加的趋势,说明球磨后的绿豆淀粉更趋近于牛顿流体。

3结论

上述实验结果表明,机械球磨方法可以有效地将绿豆淀粉非晶化,球磨一定时间后淀粉颗粒的偏光十字消失,X -射线衍射曲线的尖峰衍射特征逐渐减弱,绿豆淀粉颗粒的结晶结构受到严重破坏。球磨处理后绿豆淀粉糊的流变特性在不同浓度和温度下发生了变化,绿豆淀粉糊随着球磨时间的延长稠度系数k 不断减小,而流动特征指数m 则不断增大,说明球磨处理后绿豆淀粉糊趋向于牛顿流体的特征。

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收稿日期:2004-07-14*通讯作者基金项目:天津市教委科研项目(20039902

作者简介:乌兰(1976-,女,硕士研究生,研究方向为食品科学、天然产物开发。

金银花中绿原酸的提取及检测

乌兰,张泽生*

(天津科技大学食品工程与生物技术学院,天津300222

摘要:采用多种方法分别从金银花中提取绿原酸,用紫外光谱法和高效液相色谱法对其进行定性定量分析。同时用金银花乙醇提取物对大肠杆菌进行抗菌试验。绿原酸提取试验结果表明:用70%乙醇热回流提取是金银花中绿原酸提取的最佳方法,获得绿原酸的提取率高于其他方法,提取终产物与标准品的最高吸收峰均在324nm 处,终产物中绿原酸的含量为43.35%。抗菌试验结果表明:金银花提取物具有较强的抑菌活性。关键词:金银花;绿原酸;提取;检测;抗菌活性

Extraction and Examination of Chlorogenic Acid from Flos Lonicerae

WU Lan,ZHANG Ze-sheng*

(Food Engineering and Biology Technology,Tianjin University of Science and Technology,

Tianjin300222,China

Abstract:Optimization of the extracting method of chlorogenic acid from Flos Lonicerae was studied by several different

methods.Two different ways of Ultraviolet(UV and Visible Spectrophotometr and High Performance Liquid Chromatography (HPLC have been carried out for the quantitative and qualitative determination of chlorogenic acid in Flos Lonicerae.Inhibition test against pathogenic bacteria has been done with Flos Lonicerae ethanol and chlorogenic acid.The results of chlorogenic acid extraction showed that chlorogenic acid tiptop absorb-apex was324nm,with ethanol of70%concentration extraction was remarkably superior to other methods.The content of chlorogenic acid with70%ethanol extraction was43.35%,so the ethanol with70%concentration extraction was the optimum condition. The antibacterial action of chlorogenic acid

in vitro o n E scherichia Coliand extracted with70%ethanol from Flos Lonicerae showed that F los Lonicerae had strong antimicrobial activity.

Key words:Flos Lonicerae;chlorogenic

acid;extraction;examination;antimicrobial activity