紫花苜蓿多糖对大肠杆菌的抑菌性及其对草莓保鲜效果的研究

Antibacterial activity of polysaccharide from Medicago sativa L.on Escherichia coli and its usage on strawberry preservation

以紫花苜蓿多糖为研究对象,研究紫花苜蓿多糖对大肠杆菌的抑菌性;同时探索紫花苜蓿对草莓保鲜的效果。结果显示紫花苜蓿多糖对大肠杆菌具有抑制作用,最小抑制浓度为3 mg/mL,能够抑制大肠杆菌生长,甚至导致其死亡;可使大肠杆菌菌体黏连、出现孔洞及塌陷褶皱;增加细胞表面疏水性;破坏细胞壁和细胞膜结构,增大其通透性,导致菌体内碱性磷酸酶、钠钾ATP酶及DNA、RNA等功效物质外泄。紫花苜蓿多糖可以有效减缓草莓失重率和腐败率的升高,以及可溶性固形物和VC含量的下降。因此,紫花苜蓿多糖可以作为大肠杆菌的抑菌剂,且可以作为防腐剂应用到草莓保鲜中,该研究也可为扩展紫花苜蓿多糖应用提供理论基础。

Antibacterial activity of polysaccharides from Medicago sativa L.against Escherichia coli was studied.the effect of polysaccharides from Medicago sativa L.on preservation of strawberry was explored.The results showed that polysaccharides from Medicago sativa L.had inhibitory effect on Escherichia coli,and the minimum inhibitory concentration was 3 mg/mL,which could inhibit the growth and even kill bacteria.Polysaccharides from Medicago sativa L.could make Escherichia coli cells adhere,appear holes,collapse and folds,and increase cell surface hydrophobicity.It could also damage the cell wall and membrane structure and increase its permeability,causing the leakage of alkaline phosphatase,sodium-potassium ATP enzyme,DNA,RNA and other functional substances in the bacteria.The polysaccharides from Medicago sativa L.could effectively slow down the weight loss rate and decay rate,as well as insoluble solid and VC content decrease in strawberry.Therefore,polysaccharides from Medicago sativa L.could be used as an antibacterial agent for Escherichia coli,and a preservative in strawberry preservation.This study provides a theoretical basis for expanding the application of polysaccharides from Medicago sativa L..