Modular Biointelligent Starter Cultures for Cocoa Pulp Juice (Mucilage) Fermentation: A Scoping Review

Cocoa pulp juice (mucilage)—the fermentable liquid fraction released from the pulp surrounding Theobroma cacao beans—is an abundant yet underutilized substrate for applied fermentation. Unlike cocoa bean fermentation targeted at chocolate flavour development, cocoa pulp juice valorisation is substrate-centric and requires tailored microbial and process controls to deliver consistent beverage-quality outcomes. We conducted a scoping review to map the state of modular starter culture design and fermentation systems applied to cocoa pulp juice, with emphasis on microbial consortia, process configuration, reported metabolites, volatiles, microbial dynamics, and sensory outcomes. Eligible work was charted by starter architecture (yeast-dominated, multi-kingdom/immobilised, LAB-inclusive, non-conventional platforms), fermentation system (low-tech batch to controlled bioreactors), and outcome measures (ethanol, organic acids, aroma compounds, community composition, sensory acceptance). Evidence indicates that cocoa pulp juice supports diverse fermentation products, including wine-style beverages, kefir-like functional drinks, and aroma-forward non-alcoholic prototypes. However, comparative benchmarking of starter architectures under matched substrate conditions remains limited, and mechanistic links between microbial community transitions, quorum sensing (QS) regulation, and metabolite trajectories are insufficiently reported. QS-mediated regulation—particularly luxS/AI-2 signalling—is mechanistically plausible as a coordination layer in mixed fermentations, but its effectiveness in acidic cocoa pulp juice environments remains unvalidated. Key research priorities include comparative benchmarking of modular starter architectures, experimental validation of QS-mediated coordination in acidic pulp environments, and development of smallholder-accessible deployment and monitoring frameworks.