薯蓣属5种药食同源植物红外光谱鉴别研究

Study on Discrimination of Five Species of Medicinal and Edible Dioscorea Plants by Fourier Transform Infrared(FT-IR)Spectroscopy

采用傅里叶变换红外光谱(FT-IR)结合化学计量学鉴别不同种药食同源薯蓣植物。采集云南5种药食同源薯蓣属(淮山药、黄独、高山薯蓣、粘山药、参薯)样品红外光谱数据,选择基线校正、9点平滑、自动归一化、二阶导数等预处理方法对光谱进行优化。原始光谱显示,除粘山药样品,其余4种薯蓣属样品红外光谱相似度较高,在1 154、1 081、1 021、928、763、577 cm^(-1)附近均出现表征淀粉和一些糖苷类成分的吸收峰。选取1 800 cm^(-1)~400 cm^(-1)波段二阶导数光谱数据,结合聚类分析(HCA)和偏最小二乘判别分析(PLS-DA)法进一步挖掘红外光谱数据信息。通过HCA提取727个变量建立矩形阵列获得树状图,分类正确率为91.2%。PLS-DA模型前6个主成分累积贡献率为97.3%;得分图显示,5种样品分类效果理想。证明FT-IR结合HCA和PLS-DA方法,对5种不同种薯蓣植物的鉴别可行。

Fourier transform infrared（FT-IR）spectroscopy combined with chemometrics methods were used to discriminate different species of medicinal and edible plants of genus Dioscorea. The infrared spectra of five species of medicinal and edible plants of genus Dioscorea（Dioscorea opposita、Dioscorea bulbifera、Dioscorea henryi、Dioscorea hemsleyi、Dioscorea alata） were collected. The original spectra were optimized by 9-point smoothing,multipoint baseline correction and automatic normalization. According to the preliminary analysis of spectra data,apart from D. hemsleyi,we could find that other four species of Dioscorea plants had high similarities. The peaks at 1 154,1 081,1 021,928,763,577 cm^（-1） were strongest characterize the chemical composition of starch and some glycosides. The second derivative spectra in the region from 1 800 cm^（-1） to 400 cm^（-1） were selected for hierarchical cluster analysis（HCA）and partial least square discriminant analysis（PLS-DA）. By HCA,727 variables were extracted to build a rectangular array for obtaining the dendrogram. The rate of correct classification was 91.2 %. The results of PLS-DA showed that,the cumulative contribution of first six principal components was 97.3 %. At the same time,the classification result in scores plot was satisfactory. The study demonstrated that FT-IR spectroscopy coupled with HCA and PLS-DA could discriminate the different species of medicinal and edible plants of Dioscorea satisfactorily.