Comparison of three headspace sampling techniques for gas chromatographic analysis of cocoa masses from different varieties and origins

Abstract

Volatile organic compounds (VOCs) have a pivotal role in defining cocoa and derivatives quality and providing insights into botanical background, geographical origin, postharvest practices and industrialization. This study aimed to assess the performance of three headspace sampling techniques—solid phase microextraction (HS- SPME), headspace sorption extraction (HSSE) and dynamic headspace (DHS)— for gas chromatographic-mass spectrometric analysis of VOCs in cocoa masses and the potential for distinguishing geographical origin by applying chemometrics. Cocoa masses were elaborated from eight cacao varieties (CATIE-R1, CATIE-R4, CATIE- R6, CC-137, CCN-51, ICS-95, PMCT-58 and TSH-565) grown in two estates located in South Caribbean and Northen region of Costa Rica. A total of 139 VOCs were annotated: 101 with HS-SPME, 97 with DHS and 73 with HSSE, with predominance of alcohols, esters, ketones, pyrazines and monoterpenoids. Of these, 55 VOCs were commonly detected with the three techniques. DHS enabled higher relative peak areas than HS-SPME and HSSE, although yielding higher variability. Chemometric analysis showed that all three techniques effectively differ entiated sample origin, mainly due to VOCs such as 2-heptanol, 2-heptanone, isovaleric acid, isobutyric acid, and acetophenone. This study outlines the relevance of selecting the appropriated sampling technique for VOC analysis in cocoa masses and their potential application for traceability.