Functional Bread Development With Cocoa Shell Powder: Nutritional, Phytochemical, Antioxidant, and Microbiological Properties

Cocoa shell powder (CSP), an underutilized agro-industrial byproduct often discarded, contributes to waste and economic losses but holds potential for product development. This study explored the use of CSP for wheat-based bread development. Bread was prepared with 0%, 5%, 7.5%, and 10% CSP substitution and evaluated its proximate composition, mineral and potentially toxic metals, phytochemicals, antioxidant activity, microbial load, and antimicrobial properties. The enriched bread had improved fat (1.69%–3.57%), protein (11.46%–11.78%), dietary fiber (8.61%–9.70%), ash (0.75%–1.09%), and key minerals (Ca, K, Mg, Zn, Cu). Toxic elements, including mercury, lead, arsenic, and cadmium, were not detected in any of the bread samples. CSP addition significantly (p < 0.05) resulted in a dose-dependent increase in total polyphenols (138.0–218.0 mg GAE/100 g), flavonoids (85.0–142.0 mg QE/100 g), antioxidant activity and phenolic acid content. The bread samples showed antimicrobial activity against the tested microbes, with a more pronounced inhibitory effect on Pseudomonas aeruginosa. CSP at 7.5%–10% reduced total plate count, coliforms, and yeast/molds, and supported lactic acid bacteria growth. These findings show that CSP enhances the nutritional and functional qualities of bread while serving as an antimicrobial ingredient. The innovative application of CSP in product development underscores its potential for sustainable valorization of cocoa by-products, supporting circular economy principles and enhancing food quality and environmental sustainability.