The origin discrimination of tartary buckwheat based on the mineral elements | 基于矿质元素的苦荞产地判别研究

Chinese. 目的分析不同省份苦荞矿质元素的特点，筛选判别苦荞产地的有效指标,同时探索苦荞产地溯源和判别的方法。方法对苦荞主产区山西、甘肃、青海、四川和云南省的39个苦荞品种中的7种矿质元素Cu、Zn、Fe、Mn、Ca、P和Se的含量进行统计分析，在对7种矿质元素进行逐步筛选的基础上，应用非参数判别的K最近邻法进行判别分析。结果不同省份苦荞品种的矿质元素含量存在不同程度的差异，云南苦荞Cu、P含量最高；山西苦荞Se含量最高；青海苦荞Zn、Fe、Ca含量最高；四川苦荞Cu、Zn、Fe、Ca、P含量均最低，Mn和Se含量也较低；甘肃苦荞Mn含量最低。Se、Mn、Zn、Ca和P对苦荞分类有极显著影响，Fe和Cu对苦荞判别影响不显著；判别结果回判正确率和交互验证正确率均为97.4%。结论矿质元素含量和现代统计技术相结合的判别方法，用于苦荞产地溯源和判别是有效、可行的。

English. ObjectiveThe characteristics of mineral elements in tartary buckwheat from different provinces were analyzed in order to make choice of the effective index in tartary buckwheat origin discrimination, and to explore the method of tartary buckwheat origin traceability and discrimination.MethodSeven mineral element contents (Cu, Zn, Fe, Mn, Ca, P and Se) were analyzed in thirty-nine samples from five provinces of China（i.e., Shanxi, Gansu，Qinghai，Sichuan and Yunnan）. On the basis of stepwise selection，the K Nearest Neighbor (KNN) analysis of nonparametric discriminant was applied to data analysis.ResultThe results showed that the mineral element contents were different in tartary buckwheat varieties from different provinces. In conclusion, element contents of Cu and P were the highest in the Tartary buckwheat varieties from Yunnan while Se was the highest in those from Shanxi. However, the contents of Zn，Fe and Ca were the highest in those from Qinghai, while Cu, Zn, Fe, Ca and P were the least in those from Sichuan, and Mn was the least in those from Gansu. Then, mineral element character indexes (Zn, Mn, Ca, P and Se) affecting the classification greatly were selected with discrimination analysis. A percentage of 97.4% of correct classification was achieved by resubstitution and cross-validated.ConclusionThe determination of mineral element content in combination with modern statistical techniques should be a useful and convenient tool for the origin discrimination and standardization of tartary buckwheat.