Hannover 2010 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 26: Poster: Biomolecules

MO 26.3: Poster

Donnerstag, 11. März 2010, 16:00–18:30, Lichthof

Discrimination between Arabica and Robusta Green Coffee Using Visible Raman Spectroscopy and Chemometric Analysis — •Rasha Hassanein, Patrice Donfack, and Arnulf Materny — Jacobs University Bremen, Bremen, Germany

Raman spectroscopy is a rapid and nondestructive method, which gives information about the chemical composition of a sample without the necessity for special sample preparation. Therefore, it is ideally suited for online industrial monitoring processing. In this contribution, we will present our newest work, where we have successfully demonstrated the application of VIS Raman spectroscopy in combination with principal component analysis (PCA) as a rapid technique for the discrimination between the two coffees species, Arabica and Robusta without any extraction. Raman spectra of Arabica and Robusta revealed prominent contributions from their chlorogenic acid (CGA) and lipid content. Starting with the complete Raman spectra in the range from 500 to 3050 cm⁻¹, the spectral range between 1000 and 1750 cm⁻¹ has proven statistically significant for the distinction between the two coffee species. This part of the spectrum is dominated by the Raman bands of CGA and based on the PCA scores 93% of the spectral variation was explained by the first two principal components (PCs), suggesting that CGAs account for the most important spectral variation in the complete spectral range. Nonetheless, restricting the analysis uniquely to the spectral range from 2700 to 3050 cm⁻¹ which contains the lipid Raman bands a reliable discrimination of Arabica and Robusta coffee was also achieved.