Effects of different kinds of polysaccharides on the properties and inhibition of Monilinia fructicola of the thyme essential oil-chitosan based composite films

Abstract In order to investigate the controlled release and antifungal effect of thyme essential oil on peach fruit, the four polysaccharides such as xanthan gum, gum tragacanth, arabic gum and pullulan were used to construct the essential oil-chitosan based composite film. The physical and chemical properties of composite film and its inhibition effect on Monilinia fructicola of peach fruit in vitro and in vivo were evaluated. The results showed that thyme essential oil contained some antifungal compounds such as 2-methoxy-3- (2-propenyl)-phenol, D-limonene and thymol. The addition of four polysaccharides decreased the tensile strength and elongation at break of composite film, and caused obvious fluctuation in the peak at 3263, 2884, 1552 and 1025 cm-1. Particularly, the strong interaction was found between chitosan and arabic gum which improved the antifungal effect of thyme essential oil in vitro. Moreover, the chitosan composite film combined with arabic gum exhibited the best inhibition effect on Monilinia fructicola of peach fruit in vivo regardless of the coating of film solution or film fumigation method. The work showed that chitosan-arabic gum composite film would be a potential application for improving the antifungal effect of essential oil on the preservation of peach fruit.

摘要：为探究百里香精油（thyme essential oil）对桃果的控释效果与抗真菌作用，本研究以黄原胶（xanthan gum）、黄芪胶（gum tragacanth）、阿拉伯胶（arabic gum）及普鲁兰多糖（pullulan）四种多糖为基材，构建了精油-壳聚糖（chitosan）基复合膜。对该复合膜的理化性质，以及其对桃果褐腐病菌（Monilinia fructicola）的体外与体内抑菌效果进行了系统评价。结果表明，百里香精油含有2-甲氧基-3-(2-丙烯基)-苯酚、D-柠檬烯与百里酚等多种抗真菌活性成分。四种多糖的添加降低了复合膜的拉伸强度与断裂伸长率，并使3263、2884、1552及1025 cm⁻¹处的红外特征峰出现明显波动。尤为值得注意的是，壳聚糖与阿拉伯胶之间存在较强的相互作用，这提升了百里香精油的体外抗真菌活性。此外，无论采用膜溶液涂布还是膜熏蒸处理方式，复配阿拉伯胶的壳聚糖复合膜对桃果褐腐病菌均展现出最优的体内抑菌效果。本研究显示，壳聚糖-阿拉伯胶复合膜具备作为提升精油抗真菌性能以应用于桃果保鲜的潜在应用价值。