Climate change and cocoa flavour quality: analytical investigations to identify off-odour in cocoa products

Cocoa smoky off-flavouris due to inappropriate post-harvest processing and cannot be removed in the subsequent chocolate-manufacturing steps. To date, no reliable analytical method to detect key-analytes responsible for smoky off-flavourin incoming raw material is available and the sensory tests are time-consuming. This study aims to develop an analytical methodto detect smoky markers, suitable for quality control. A top-down procedure was applied: the cocoa volatilome was first profiled by headspace solid phase microextration(HS-SPME) combined with comprehensive two-dimensional gas chromatography-mass spectrometry (GCxGC-TOF-MS) from a set of representative smoky and non-smoky samples; advanced fingerprinting revealed the chemicals responsible for the off-flavour. The resultsserved to develop a 1D-GC method suitable for routine application. Ten identified smoky markers were subjected to accurate quantification, thereby defining operative ranges to accept/reject incoming bean samples.A step ahead was devoted to automatically speeding up the controls through aMS-enose platform coupled with suitable chemometric modellingto classify smoky and non-smoky samples and cross-validated by the confirmatory quantitative method through HS-SPME-GC-MS.Thus, it was successfully developed an objective and automatic analytical decision maker suitable for the control at multistep level on the chocolate production chain.