Valorization of Ghanaian cocoa processing residues as extractives for value-added functional food and animal feed additives – A review

Abstract

Cocoa farming and processing are the main preoccupations of Ghana's cocoa-based pillar industry, generating annual quantities of 858,720 tons of cocoa pod husk (CPH) and 180,000 tons of cocoa bean shell (CBS) as cocoa processing residues (CPRs) and solid waste in Ghana. Numerous nonstructural extractable compounds with bioactivity are being intensively explored for their potential applications in plant-based functional food and animal feed additives. This review presents the potential applications of extractives from CPH and CBS in Ghana and summarizes and discusses the recent advanced technologies for their extraction. The findings of this review demonstrate that CPR extractives vary based on the type of cocoa, geographical location, and extraction method. Phenolic compounds, pectin, and alkaloids are the primary extractives found in CPRs, and their applications in functional food and animal feed additives hold promise. Microwave-assisted extraction, ultrasonic-assisted extraction, subcritical water extraction, supercritical fluid extraction, and the optimization of solvent extraction are the most recently developed and advanced technologies due to their improved extraction efficiency. However, they still require further improvements to fully realize their efficiency potential. Key factors for improving these technologies include reducing extraction time, lowering temperatures to prevent compound degradation, enhancing extraction selectivity, simplifying the extraction system's complex configuration for improved operation and energy efficiency, and minimizing chemical usage. The development and commercialization of residue-extractive technology offer promising new approaches for valorizing the cocoa processing residues, as well as the related food and animal feed sectors, not only in Ghana but also in cocoa-producing countries worldwide.