Selection of discriminant markers for authentication of Asian palm civet coffee (Kopi Luwak): a metabolomics approach.

Kopi Luwak, an exotic Indonesian coffee, is made from coffee berries that have been eaten by the Asian palm civet ( Paradoxurus hermaphroditus ). Despite being known as the world's most expensive coffee, there is no reliable, standardized method for determining its authenticity. GC-MS-based multimarker profiling was employed to explore significant metabolites as discriminant markers for authentication. Extracts of 21 coffee beans ( Coffea arabica and Coffea canephora ) from three cultivation areas were analyzed and subjected to multivariate analyses, principal component analysis, and orthogonal projection to latent structures discriminant analysis. Citric acid, malic acid, and the inositol/pyroglutamic acid ratio were selected for further verification by evaluating their differentiating abilities against various commercial coffee products. The markers demonstrated potential application in the differentiation of original, fake Kopi Luwak, regular coffee, and coffee blend samples with 50 wt % Kopi Luwak content. This is the first report to address the selection and successful validation of discriminant markers for the authentication of Kopi Luwak.