Discrimination of Green Arabica and Robusta Coffee Beans by Raman Spectroscopy
Discrimination of Green Arabica and Robusta Coffee Beans by Raman Spectroscopy
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DOI：
10.1021/jf101999c
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发表时间：
2010-11-10
影响因子：
6.1
通讯作者：
Hildebrandt, Peter
中科院分区：
文献类型：
--
作者：
Keidel, Anke;von Stetten, David;Hildebrandt, Peter
本文提出了一种方法，可以应用作为一个准确和快速的工具，用于分类咖啡豆的基础上，具体的咖啡豆含量。使用具有1064 nm激发的傅里叶变换拉曼光谱，可以监测绿色咖啡豆中咖啡醇的特征拉曼带，而无需对咖啡豆进行化学和物理处理。该程序进行了优化的基础上，83和125测量的整个和地面豆，分别使用两个不同物种的咖啡样品，阿拉比卡咖啡L。和Coffee canephora L.（var. Robusta），以及不同的起源（亚洲，非洲和南美洲）。咖啡豆中咖啡豆酚的相对贡献可以通过光谱的成分分析定量确定，产生与咖啡豆中咖啡豆酚的相对含量成比例的光谱咖啡豆酚指数（sigma（ka））。光谱测量和分析的再现性为3.5%。同一类型和产地的单个咖啡豆揭示了sigma（ka）值的分散。尽管如此，阿拉比卡和罗布斯塔样品之间的明确区别是可能的基础上，单豆测量的sigma（ka）值是大于和小于10阿拉比卡和罗布斯塔咖啡，分别。测量整个和地面豆提供了非常相似的结果，尽管咖啡豆内的分布不均。与传统的分析技术不同，本方法的单豆灵敏度还可以允许快速检测低价值罗布斯塔咖啡与高质量和更昂贵的阿拉比卡咖啡的不需要的混合物。
This paper presents an approach that may be applied as an accurate and rapid tool for classifying coffee beans on the basis of the specific kahweol content. Using Fourier-transform Raman spectroscopy with 1064 nm excitation it is possible to monitor the characteristic Raman bands of kahweol in green coffee beans without chemical and physical processing of the beans. The procedure was optimized on the basis of 83 and 125 measurements of whole and ground beans, respectively, using coffee samples of two different species, Coffee arabica L. and Coffee canephora L. (var. Robusta), and different origins (Asia, Africa, and South America). The relative contribution of the kahweol in individual beans can be determined quantitatively by means of a component analysis of the spectra, yielding a spectral kahweol index (sigma(ka)) that is proportional to the relative content of kahweol in a coffee bean. The reproducibility of the spectroscopic measurement and analysis was found to be 3.5%. Individual beans of the same type and origin reveal a scattering of the sigma(ka) values. Nevertheless, an unambiguous distinction between Arabica and Robusta samples is possible on the basis of single-bean measurements as the sigma(ka) values are greater than and less than 10 for Arabica and Robusta coffees, respectively. Measurements of whole and ground beans afforded very similar results, despite the heterogeneous distribution of kahweol within a bean. Unlike conventional analytical techniques, the single-bean sensitivity of the present approach may also allow for a rapid detection of unwanted admixtures of low-value Robusta coffee to high-quality and more expensive Arabica coffee.