Fatty acid profiles as discriminant parameters for coffee varieties differentiation.

The fatty acid contents of coffee lipid extracts have been determined by capillary gas chromatography. Ten fatty acids were considered: myristic (C14:0), palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0), oleic (C18:1), linoleic (C18:2), linolenic (C18:3), arachidic (C20:0), eicosenoic (C20:1) and behenic acid (C22:0). The analyzed coffee samples belonged to arabica and robusta varieties and were either green or roasted coffee beans. The lipids were Soxhlet extracted from ground coffee beans with hexane, and the fatty acids were determined as their corresponding methyl esters. Fatty acids contents were considered as chemical descriptors to differentiate coffee varieties. Several Pattern Recognition methods, Principal Component Analysis and Linear Discriminant Analysis allowed discrimination between green and roasted arabica and robusta coffees.