柑橘果胶低聚糖抑菌活性的研究

Study on antibacterial activity of citrus pectin oligosaccharide

初步探究不同酶解条件(水解时间和初始pH)下制备的柑橘果胶低聚糖对常见食品污染菌(大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌)的抑菌活性.果胶低聚糖的制备方法:20g/L果胶,4g/L(178.03U/mL)聚半乳糖醛酸酶(PG酶),45℃,pH 4.2条件下水解180min.实验结果表明:不同聚合度的果胶低聚糖对不同菌株的抑制活性存在不同,果胶低聚糖对金黄色葡萄球菌和枯草芽孢杆菌具有较高的抑制活性.此外,应用杯碟法测定了果胶低聚糖的最小抑菌浓度,通过对桔汁的防腐实验,比较了柑橘果胶低聚糖与市售食品防腐剂的抑菌活性,结果表明:在最小抑菌浓下,柑橘果胶低聚糖较市售防腐剂具有更好的抑菌活性;根据桔子汁澄清度的观察,低聚糖的防腐效果比市售防腐剂的效果更显著.因此,柑橘果胶低聚糖可以作为良好的天然食品防腐剂,在食品行业具有潜在的应用价值.

The effects of enzymatic hydrolysis time and the initial pH on antibacterial activity of oligosaccharides towards food bacteria including Escherichia coli,Staphylococcus aureus and Bacillus subtilis were studied.When 20 g/L pectin was hydrolyzed by 4 g/L（178.03 U/mL）of polygalacturonase（PG）in sodium citrate buffer（pH 4.2）at 45 ℃ for 180 min,the oligosaccharides with best antibacterial activity was obtained.Different strains showed different levels of sensitivity to pectin oligosaccharides with different degree of polymerization,and Staphylococcus aureus and Bacillus subtilis showed higher sensitivity.In addition,antibacterial activity of pectin oligosaccharides and commercial food preservatives were compared by cylinder plate method and antisepsis experiments of orange juice.The results showed that the pectin oligosaccharides had better antibacterial activity than commercial preservatives in respect of minimum inhibitory concentration.Based on the observation of orange juice clarity,the preservative effect of oligosaccharides was more remarkable than the commercial preservatives.Therefore,pectin oligosaccharides would have great potential used as natural preservatives in the food industry.