Organic and conventional coffee differentiation by NMR spectroscopy

The present study reports the application of 1H NMR profiling for the differentiation of organic and conventional Coffea arabica roasted coffee samples. NMR data of coffees with different geographical origins have been analyzed by chemometrics for a possible metabolite differentiation. Classification methods like OPLS-DA allowed to highlight fatty acids, β-(1-3)-d-galactopyranose, β-(1-4)-d-mannopyranose, quinic acid and its cyclic ester as the characteristic metabolite for organic coffee, while trigonelline, CGA isomers, caffeine and acetate for conventional ones. The use of Orthogonal Signal Correction (OSC) filters improved the samples differentiation confirming fatty acids, β-(1-3)-d-galactopyranose, quinic acid and its cyclic ester as the major metabolites characterizing organic roasted coffee, while conventional resulted enriched in trigonelline and CGA isomers. The preliminary data here presented indicated 1H NMR spectroscopy as a valid method for farming differentiation of C. arabica roasted coffee.