Differentiation of cocoa nibs from distinct origins using comprehensive two-dimensional gas chromatography and multivariate analysis

•Cocoa nib samples were analyzed by two-dimensional gas chromatography.•Methodology was proposed for differentiation of nibs from Brazil and Ivory Coast.•Fisher ratio was used for selection of variables responsible for differentiation.•Principal component analysis was used for separation visualization.•15 compounds were identified to be responsible for separation.

Headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography was used for identification of volatiles compounds responsible for differentiation between cocoa nibs from Brazil and Ivory Coast. The unfolded GC × GC with Flame Ionization Detector (FID) chromatograms were first aligned using the correlation optimization warping (COW) algorithm and normalized. After that, Fisher ratio was calculated for each variable, and a threshold value was chosen to select the variables that best promote a separation of nibs samples from different sources in a principal component analysis (PCA) model. To identify the relevant compounds for the separation, representative samples of each source were analyzed in the same conditions by GC × GC with detection by quadrupole mass spectrometry. Finally, the average peak volumes for each key compound obtained for both classes were compared using a Student t-test and it was possible to identify 15 volatile compounds responsible for differentiation between cocoa nibs from Brazil and Ivory Coast.

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