Effect of cocoa roasting time on volatile composition of dark chocolates from different origins determined by HS-SPME/GC-MS

Abstract

In this study the volatile composition of six samples of dark chocolates varying in the cocoa roasting time (30.5, 34.5 and 38.5 min) and geographical origin (Ecuador and Ghana) was characterized by headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS). One hundred and twenty-one different compounds were identified using a carboxen/polydimethylsiloxane (CAR-PDMS) fiber comprising acids, alcohols, aldehydes, alkanes, esters, furans, ketones, nitrogen compounds, pyran derivatives, pyrazines, pyrroles and thiazoles. The effect of roasting time on the volatile composition of chocolates depended on their geographical origin. Principal component analysis (PCA) was applied to volatile composition of the six dark chocolate samples. Eight different groups of compounds were established according to the position of the aroma compounds on the PC plot and accordingly to variation among samples. Therefore, volatile compounds that appeared or disappeared during roasting of cocoa from each origin or both origins were identified.

Keywords

• dark chocolate
• cocoa origin
• roasting time
• hs-spme
• gc-ms
• volatile compounds
• flavour