During processing, cocoa bean shells (CBS) are de-hulled from the bean and discarded as waste. Undermined by its chemical and bioactive composition, CBS is abundant in dietary fiber and phenolic compounds that may serve the valorization purpose of this by-product material into prebiotic and functional ingredients. In addition, the cell-wall components of CBS can be combined through enzymatic feruloylation to obtain feruloylated oligo- and polysaccharides (FOs), further enhancing the techno-functional properties. FOs have attracted scientific attention due to their prebiotic, antimicrobial, anti-inflammatory and antioxidant functions inherent to their structural features. This review covers the chemical and bioactive compositions of CBS as well as their modifications upon cocoa processing. Physical, chemical, and enzymatic approaches to extract and bio-transform bioactive components from the cell wall matrix of CBS were also discussed. Although nonspecific to CBS, studies were compiled to investigate efforts done to extract and produce feruloylated oligo- and polysaccharides from the cell wall materials.

Cocoa bean shells (CBS), a by-product of the cocoa industry, from two cacao varieties and obtained after selected processing conditions (fermentation, drying, roasting) were characterized in terms of their chemical composition, where they were found to be a great source of carbohydrates, specifically dietary fiber, protein, ash, and polyphenols, namely quercetin, epicatechin, and catechin. Cell wall polysaccharides were isolated by alkaline extraction (0.5 M or 4 M KOH) and were found to be enriched primarily in pectic polysaccharides (80.6–86%) namely rhamnogalacturonan and arabinogalactan as well as hemi- cellulosic polysaccharides (13.9–19.4%). Overall, 0.5 M KOH polysaccharides were favored having provided a diverse profile of neutral sugars and uronic acids. When tested for the promotion of the growth of selected probiotic strains, CBS cell wall polysaccharides performed similarly or more than inulin and rhamnogalacturonan based on the prebiotic activity scores. The short-chain fatty acid profiles were characterized by high amounts of lactic acid, followed by acetic and propionic acid.