Authentication of Coffee Bean Variety by Near-infrared Reflectance Spectroscopy of Dried Extract

Abstract

The potential of near-infrared (NIR) reflectance spectroscopy for discriminating between coffee beverage prepared from pure Arabica, pure Robusta and blends of these two varieties was investigated. Dried beverages were produced by both lyophilisation and air-drying under vacuum on glass-fibre filter paper. Spectral collections were treated by principal component and factorial discriminant analyses. Using the wavelength range 1100–2498 nm, only three of 65 test samples were misclassified when the filter paper approach was used. When freeze-dried coffee beverages were analysed, nine of the 65 test samples were misclassified. The basis for this discrimination appears to involve caffeine and/or other alkaloids.