Discrimination of geographical origins of coffees by paper spray mass spectrometry

Abstract

Coffee is one of the most important agricultural commodities, and the demand for specialty coffee and single-origin coffees is also increasing significantly. Methods that can effectively differentiate the origins of coffee is tremendously beneficial. In this work, paper spray – mass spectrometry (PS-MS) was used as a tool for collecting chemical profiles of coffees for differentiating their origins. The acquired data was then processed by principal component analysis (PCA) and linear discriminant analysis (LDA), resulting in successful identification of the origins of coffee with prediction accuracies of 80-100%. Studies with the aforementioned performance include the discrimination of Arabica vs Robusta, Arabica coffees from different geographical origins, Robusta coffees from different geographical origins, and geographical origins of Arabica coffees within each province in Thailand. Furthermore, headspace solid-phase microextraction (HS-SPME) in combination with gas chromatography – mass spectrometry (GC-MS) was also evaluated as an alternative method for collection of chemical data. This method was found to also provide good performance for the classification of coffees. In brief, the overall workflow in both cases is simple, with little sample pre-treatment, but yet effective for distinguishing origins of coffee.