NMR metabolic and chemometrics study of coffee

Coffee, one of the most popular and appreciate beverages worldwide, is a mixture obtained by blending coffee beans coming from different countries to achieve specific organoleptic characteristics that could fulfil both market and consumer requests. lts particular high economical value often implies adulteration practises that could involve geographical origin. For this reason it is very important from both economic and qualitative point of view, to develop new analytical methods to guarantee the quality of coffee in terms of both authenticity and origln. From the chemical point of view, coffee represents a very complex matrix, being constituted by several class of compounds. ln this contest, the metabolomic approach could represent a suitable tool to investigate simultaneously all soluble components. Nuclear Magnetic Resonance (NMR) was already proposed (1-3) as fast and direct method capable to analyze the metabolite content of food matrices with a single experiment, high reproducibility, limited experimental time and with no need of any derivatization or treatment of samples. In this work NMR studies on roasted and green coffee beans coming from the main producers, America, Asia and Africa were presented with the main aim of geographical origin investigation. Particularly only Coffea Arabica was considered being the most appreciated specie by the consumers due to its flagrancy, sweetness and fruity taste thus imposing higher market prices and increasing its susceptibility to frauds. ln this work O2PLS-DA was performed on NMR data leading to a clear differentiation of samples according to their origin for both roasted and green coffee beans highlighting characteristic metabolites for American, Asian and African coffee samples.