Comparative evaluation of the physicochemical properties and prebiotic potential of cocoa (Theobroma cacao L.) bean shell and commercial cocoa powders with varying degrees of alkalization

Cocoa bean shell (CBS) is a byproduct of cacao processing that is of high nutritional and functional value. However, its application in food is still limited due to some undesirable properties. The alkalization process can further broaden its use as a food ingredient by modifying its properties. This study investigated the physicochemical and prebiotic properties of variously alkalized CBS powders, and compared them with commercial alkalized cocoa powders. Samples were analyzed for pH, titratable acidity, water activity, color, proximate and bioactive composition, phenolic profile, antioxidant properties, and prebiotic potential. Findings revealed that the varying degrees of alkalization led to reduction in values of CBS properties including titratable acidity (23–88%), fiber (4–11%), total phenolic content (15–41%), and antioxidant activity (13–34%). Meanwhile, the prebiotic potential of the laboratory-produced CBS powder samples was confirmed by the computed positive prebiotic activity scores (0.75–1.05). Compared to commercial cocoa powders, alkalized CBS powders exhibited lower fat (7.43–7.98 g/100 g vs 10.16–12.18 g/100 g), and higher fiber (8.71–9.76 g/100 g vs 0.42–0.68 g/100 g) and total phenolic content (14.27–24.02 mg GAE/g vs 12.46–13.30 mg GAE/g). These results highlight the potential of alkalized CBS powder as a functional food ingredient. The varying levels of alkalization expand its potential applications across a range of food products.