四种药用植物提取物抑菌保鲜活性的研究

Antimicrobial and preservation activity of four kinds of medicinal plant extracts

应用滤纸片扩散法、微量稀释法等方法研究银杏叶、当归、党参(野生)、藏茵陈4种药用植物水和乙醇提取物抑菌效果以及在食品保鲜方面的应用。结果表明水提取物均无明显的抑菌活性;银杏叶、藏茵陈醇提取物对金黄色葡萄球菌有抑菌活性,对大肠杆菌、酿酒酵母无明显抑菌效果,对金黄色葡萄球菌的最低抑菌浓度分别为450、160μg/mL。发现随着基质pH的改变,2种提取物的最低抑菌浓度随pH的增加而升高,但变化趋势较常用防腐剂山梨酸钾和苯甲酸弱,在pH5～8的范围,2种提取物的最低抑菌浓度均低于山梨酸钾。在模式食品中将提取物与山梨酸钾、苯甲酸进行联合添加具有协同增效抑菌活性,可降低化学防腐剂的用量,尤其是与苯甲酸联合添加,可在一周内完全抑制金黄色葡萄球菌的生长。

Based on disc diffusion assay and the microdilution method, this study investigated the inhibitory effect of water and ethanol extracts of four kinds medicinal plant, and possible applications in food preservation. The ethanol-soluble extracts of ginkgo biloba and Tibetan capillaris were shown to have some antimicrobial effects against S.aureus, but no antimicrobial effects against E.coli and S.cerevisiae, and all the water extracts had no inhibitory effect on the above three bacteria. The minimum inhibitory concentration against S.aureus is 450 μg/mL and 160 μg/mL, respectively. The minimum inhibitory concentration of the two extracts increased with pH increasing, but the trends were weaker than potassium sorbate and benzoic acid. Under alkaline conditions, the minimum inhibitory concentrations of the two extracts were better than potassium sorbate. In mode food, extracts exhibited antimicrobial activities in combination with the two preservatives, especially benzoic acid, can completely inhibit the growth of S.aureus.