Cocoa smoky off-flavor: Chemical characterization and objective evaluation for quality control

Cocoa smoky off-flavor is due to inappropriate post-harvest processing and cannot be removed in the subsequentchocolate-manufacturing steps. To date, no reliable analytical method to detect key-analytes responsible forsmoky off-flavor in incoming raw material is available. This study aims to develop an analytical method, suitablefor quality control, to detect smoky markers. The cocoa volatilome wasfirst profiled by headspace solid phasemicroextration combined with comprehensive two-dimensional gas chromatography-mass spectrometry from aset of representative smoky and non-smoky samples; advancedfingerprinting revealed the chemicals responsiblefor the off-flavor. The results served to develop a 1D-GC method suitable for routine application. Ten identifiedsmoky markers were subjected to accurate quantification, thereby defining operative ranges to accept/rejectincoming bean samples. On average, these markers are present in smoky samples at 7 to 125 fold concentrationsvs.those in non-smoky beans, ranging from 32.5 ng/g for naphtalene to 721.8 ng/g for phenol