茶叶红外光谱的阵列相关系数特性分析

研究了红外光谱在茶叶品质鉴别中的应用。利用傅里叶红外光谱仪测得了特级铁观音、特级龙井和生饼普洱三种典型茶叶的标准红外光谱图, 通过谱图的直观分析发现各种茶叶的红外吸收均可以分为几个大的区域, 并且茶叶的主体成份相似导致谱图具有一定的相似性, 因此直观上很难将各谱图区分。为了强调特征部分的比对, 更好地显示出不同种类茶叶之间的差异, 借助数学方法和计算机程序对这几种茶叶谱图的多波段阵列相关性进行了分析, 发现在指纹区内的1130～1570 cm-1波数范围中几种茶叶的相关系数比整体波数范围以及其他能有效表征茶叶成份特征的波数范围内小, 即所反映的此范围内的指纹信息更明显, 更容易判断结构特征的细微变化, 利用此波数范围可以对三种茶叶进行区分和判别。

The Characteristic Analysis of Correlation Coefficient Array for Infrared Spectra of Tea

The application of infrared spectral on quality identification of tea is studied. The standard infrared spectra of special grade tieguanyin, special grade Longjing and fresh Pu′er typical tea are respectively measured by Fourier transform infrared spectrometer. By the visual analysis on the infrared spectra it is found that the infrared absorptions of several kinds of tea can all be divided to several big areas, furthermore the spectra are similar induced by the similar of primary contents of tea. So it is difficult to visual distinguish the different spectra. In order to emphasize the contrast of character parts, better display the discrepancy of different kinds of tea, in virtue of mathematical method and computer program the array relativity of spectra is analyzed. The results show that the correlation coefficients of several kinds of tea in the region of wavenumber 1130～1570 cm-1 which belongs to the fingerprint region are smaller than the whole and other regions of wavenumber that can effectively sign the component character of tea, that is the reflected fingerprint information in this region is more obvious, the small change of structure character is more easily judged. The three kinds of tea can be distinguished by this region of wavenumber.