Use of Gas Chromatography–Olfactometry in combination with Solid Phase Micro Extraction for cocoa liquor aroma analysis

Aroma of cocoa liquor extracted by using Solid Phase Micro Extraction with polydimethylsyloxane–divinylbenzene polymer was analyzed in Gas Chromatography-Olfactometry. Headspace extraction of cocoa odour-active compounds for 30 min at temperature of 60°C followed by GC separation elaborated with column oven initial temperature at 60°C and ramped at 5°C/min to reach 220°C identified most of the odour-active compounds including wide range of alcohols, carboxylic acids, aldehydes, ketons, esters, pyrazines, and amines. Cocoa specific aroma attributed in terms of sweet, nutty, caramel and chocolate-like notes were associated with trimethylpyrazine, tetramethylpyrazine, 2,3-butanediol, dodecanoic acid, phenylethyl alcohol, ethanone, benzeneacetaldehyde and 1,4-bis(morpholinoacetyl)piperazine. Meanwhile defective cocoa aroma such as smoky and rancid were generated by benzeneacetaldehyde, alphaethylidene; trimethylpyrazine, and trans-2,3-dimethyloxirane.