Advances in Cocoa Aroma Research: From Microbial Fermentation to Roasting and Sensory Complexity

Cocoa aroma is increasingly understood as the predictable outcome of a genotype–terroir–process system, rather than an incidental by-product of post-harvest practices. Aroma formation depends on interactions between genetic background, environmental conditions, and processing operations that shape precursor availability and transformation pathways. This review integrates evidence from chemical analysis, microbial ecology, and process engineering. It examines how precursor pools, reducing sugars, free amino acids, organic acids, and lipids are established during cultivation, restructured during fermentation, and converted during roasting. Flavor development yields key odorants, including alkylated pyrazines, Strecker aldehydes, esters, aromatic alcohols, and lactones. Terroir factors, microclimate, soil, and timing influence mucilage composition and microbial selection, while genetic variation modulates volatile profiles and traceability of origin. The review proposes quality strategies, including chemical markers, origin-specific roasting, and defect prevention. A bibliometric analysis identifies trends and gaps, highlighting the need for standardized protocols and open datasets to improve reproducibility and decision-making across the cocoa value chain. These insights support the integrated control of fermentation dynamics, drying kinetics, and roasting parameters to optimize aroma expression and reduce batch-to-batch variability. Future research should link omics data with sensory models to enable predictive quality design in cocoa processing systems worldwide and strengthen sustainability.