三种李果皮蜡质的结构与成分比较

Comparison of Wax Structure and Composition of Plum Peel From Three Varieties

为探明不同品种李果皮蜡质特性,选择3种李(空心李、蜂糖李和脆红李)为试验材料,采用扫描电子显微镜观察果皮表面结构,通过非靶向气相色谱-质谱(GC-MS)代谢组学技术对果皮蜡质的成分进行分析。结果表明,空心李果皮有大量堆叠的片状和杆状蜡质结构,蜂糖李果皮有颗粒状蜡质晶体以及大量片状蜡质结构,脆红李果皮有片状和大量堆叠的杆状蜡质结构。空心李果皮蜡质含量最高,蜂糖李次之,脆红李最低。3种李果皮蜡质中共检测出7类87种成分,其中伯醇含量最高、烷烃次之、酮类含量最少。主成分分析显示3种李果皮蜡质组分相对含量差别较大,组分区分明显;聚类热图分析显示空心李与脆红李的蜡质成分相近,与蜂糖李蜡质成分差异较大。李果皮上的片状结构蜡质与蜡质成分中醇类和烷烃含量高相关,并且对称二元醇和三萜类化合物对杆状蜡质以及白霜状蜡质的形成起到重要作用。本研究结果为进一步开展贮藏时期李果皮蜡质结构和成分变化研究提供了理论依据。

To explore the wax characteristics of plum peel of different varieties,three varieties of plum(Kongxin,Fengtang,Cuihong)were used.The surface structure of pericarp was characterized by scanning electron microscope,and the compositions of peel wax were detected and analyzed using non targeted gas chromatography-mass spectrometry(GC-MS)metabonomics.The results showed that an abundance of stacking,flaky and rod-like waxy structures were found in Kongxin;granulated waxy crystals and an abundance of stacking,flaky waxy structures in Fengtang;and a small amount of flaky and stacking,rod-like structures in Cuihong.The peel wax content of Kongxin was the highest,followed byFengtang,and the lowest was Cuihong.A total of 87 wax components of 7 categories were analyzed in the three plum peel waxes.Primary alcohol showed the highest content,followed by alkan,and keton was the least abundant.Principal component analysis showed that the relative contents of waxy components in the peel of the three plums were quite different,and the groups were clearly divided.Clustering heatmap analysis showed that the wax compositions of Kongxin and Cuihong were similar,which were quite different from those of Fengtang.The large number of flake structure waxes on plum peel were related to the number of alcohols and alkanes in the three plum waxes.Symmetrical diols and triterpenoids played an important role in the formation of rod wax structure and frost wax.The results of this study provide theoretical basis for further understanding the response and function of plum peel wax during storage.