代表性热带水果及其废弃物提取液的抑菌效果研究

目的研究热带水果(火龙果、杨桃、菠萝、芒果、荔枝、龙眼、绿橙和莲雾)以及水果废弃物(龙眼壳、荔枝壳、龙眼核、香蕉皮、火龙果皮、菠萝蜜芯和菠萝蜜仁)的乙醇、丙酮、乙酸乙酯和正己烷溶剂提取液对沙门氏菌、单增李斯特菌、金黄色葡萄球菌和大肠杆菌O157:H7的抑菌活性。方法采用平板打孔法测量抑菌圈的大小,以表示提取液的抑菌活性。通过测量菌株生长曲线,确定提取液对细菌的生长抑制率。结果乙醇、丙酮提取液的抑菌效果均较好。提取液对单增李斯特菌、金黄色葡萄球菌和大肠杆菌O157:H7抑菌效果最好。火龙果、芒果和菠萝提取液的抑菌效果最好。菠萝提取液的最小抑菌稀释比例为1/10,其他提取液为1/100。碱性条件下,龙眼壳提取液抑菌活性增强,其他提取液在酸性条件下抑菌活性较强。各类提取液具有较好的耐热性。火龙果、芒果、菠萝的乙醇提取液中金黄色葡萄球菌的生长明显受到抑制,提取液可改变该菌的细胞膜渗透性。结论芒果、菠萝、龙眼壳、火龙果、火龙果皮、莲雾、荔枝壳、龙眼核、菠萝蜜芯和菠萝蜜仁的提取液具有一定抑菌活性。火龙果、芒果、菠萝的乙醇提取液对金黄色葡萄球菌有明显抑制作用并可破坏细胞膜渗透性,为有效防控食源性致病菌提供了基础数据。

Antimicrobial activity of several tropical fruits and their wastes

Objective To investigate antimicrobial activity of solvent extracts of ethanol, acetone, ethyl acetate and hexane of tropical fruits (dragon fruit, starfruit, pineapple, mango, litchi, longan, orange and wax apple) and their wastes (longan shell, litchi shell, longan seed, banana peel, dragon fruit peel, jackfruit seed and core) against foodborne pathogens (Escherichia coil O157:H7, Salmonella enteritidis, Listeria monocytogenes and Staphylococcus aureus). Methods The size of the bacteriostatic circle was measured by the plate perforation method to indicate the bacteriostatic activity of the extract. The growth inhibition rate of the extract on bacteria was determined by measuring the growth curve of the strain. Results Extracts by ethanol and acetone showed the higher antimicrobial activity against pathogens. Extracts had the strongest inhibition against Staphylococcus aureus, Escherichia coil O157:H7 and Listeria monocytogenes. Ethanol extracts of dragon fruit, mango and pineapple had the highest antimicrobial activity against pathogens. The minimum inhibitory ratio of pineapple ethanol extract was 1/10 and other extracts were 1/100. Antimicrobial activity of longan shell ethanol extract was higher in alkaline condition, whereas other extracts showed higher antimicrobial activity in acidic condition. All kinds of extracts had a good thermostability. The growth of Staphylococcus aureus in the ethanol extract of dragon fruit, mango and pineapple was obviously inhibited, and the extract could change the cell membrane permeability of the bacteria. Conclusion Extracts of mango, pineapple, longan shell, dragon fruit, dragon fruit peel, wax apple, litchi shell, longan seed, jackfruit seed and core showed antimicrobial activity against pathogens. Ethanol extracts of dragon fruit, mango and pineapple could inhibit the growth and destroy the membrane permeability of Staphylococcus aureus. The results from this study help in providing the basic information for foodborne pathogens prevention.