Julius Kühn Institute, Institute for Ecological Chemistry, Plant Analysis and Stored Product Protection, Königin-Luise-Strasse 19, D-14195 Berlin, Germany.
J Agric Food Chem. 2014 Apr 23;62(16):3537-47. doi: 10.1021/jf405752x. Epub 2014 Apr 14.
Various vibrational spectroscopy methods have been applied to classify different fennel chemotypes according to their individual profile of volatile substances. Intact fennel fruits of different chemotypes could be successfully discriminated by attenuated total reflectance Fourier transform infrared (ATR-FTIR) and near infrared (NIR) spectroscopy. Solvent extracts (CCl4) of the considered fennel fruits showed characteristic fingerprints with marker bands related to the individual volatile components (trans-anethole, fenchone, estragole, piperitenone oxide, γ-asarone, limonene) for ATR-FTIR and FT-Raman spectroscopy. Especially νC═C and νC═O absorption bands contribute to the different spectral profiles. On the basis of hierarchical cluster analysis, the considered fennel accessions were classified according to gas chromatographic (GC) and vibrational spectroscopic data. Furthermore, even a discrimination of "sweet" and "bitter" fennel fruits, both belonging to the trans-anethole chemotype, could be successfully performed. All vibrational spectroscopical techniques used in this study are rapid and easy to apply. Hence, they allow different fennel chemotypes to be reliably distinguished and can also be used for on-site measurement in free nature.
各种振动光谱方法已被应用于根据挥发物的个体特征来对不同类型的茴香进行分类。通过衰减全反射傅里叶变换红外（ATR-FTIR）和近红外（NIR）光谱，可以成功区分不同化学型的完整茴香果实。所考虑的茴香果实的溶剂提取物（CCl4）在ATR-FTIR 和 FT-Raman 光谱中显示出具有特征指纹的标记带，这些标记带与各个挥发性成分（反式茴香脑、葑酮、黄樟素、胡椒酮氧化物、γ-细辛脑、柠檬烯）有关。特别是 νC═C 和 νC═O 吸收带对不同的光谱轮廓有贡献。基于层次聚类分析，根据气相色谱（GC）和振动光谱数据对所考虑的茴香进行了分类。此外，即使是对属于反式茴香脑化学型的“甜”和“苦”茴香果实的区分也能成功完成。本研究中使用的所有振动光谱技术都快速且易于应用。因此，它们可以可靠地区分不同的茴香化学型，也可用于野外的现场测量。
