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目的利用可见/近红外光谱技术对产自不同地区的晋谷21号小米进行溯源研究。方法使用近红外光谱仪获取产自洪洞、浮山、沁县3个不同地区的晋谷21号小米400~1004nm波段范围内的漫反射光谱;对光谱分别进行多元散射校正法(multiple scattering correction,MSC)、一阶导数法(first derivative,1St-D)预处理;对预处理光谱进行主成分分析,全交叉验证确定最佳主成分数量,获取主成分;同时选择预处理光谱特征波长。使用马氏距离法、线性判别法建立判别模型,最后用未知样品的验证准确率来表示模型的判别效果。结果原始光谱和MSC处理光谱提取特征波长分别建立的产地判别模型对3个不同产地的小米判别完全准确;1St-D处理光谱基于7个主成分结合马氏距离法和基于9个主成分结合线性判别法建立的2种判别模型对3个不同产地的小米亦实现完全准确判别。结论可见/近红外反射光谱技术用于小米产地的判别具有可行性,本研究可为小米产地的快速判别应用中提供技术基础。
Objective To study the traceability of millet in Jingu No.21 from different regions by visible / near infrared spectroscopy. Methods The near-infrared spectrometer was used to obtain the diffuse reflectance spectra in the range of 400 ~ 1004nm in Jingu No.21 millet from 3 different areas of Hongdong, Fushan and Qinxian. The spectra were subjected to multiple scattering correction (MSC) ), And the first derivative (1St-D). The principal component analysis (PCA) was performed on the preprocessed spectra. The optimal principal components were obtained by cross-validation and the principal components were obtained. At the same time, the pretreated spectral characteristic wavelengths were selected. Mahalanobis distance method and linear discriminant method are used to establish the discriminant model. Finally, the discriminant accuracy of the unknown sample is used to represent the discriminant effect of the model. Results The origin discriminant model established by the original spectrum and the characteristic wavelength extracted by the MSC treatment was completely accurate for discriminating three millet from different habitats. The 1St-D treatment spectrum was based on seven principal components combined with Mahalanobis distance and nine principal components based on linear The two discriminant models established by the discriminant method can also completely and accurately distinguish the three millet from different areas. Conclusion Visible / near-infrared reflectance spectroscopy is feasible for discriminating the origin of millet. This research can provide the technical basis for the rapid discriminant application of millet origin.