Utilising cocoa (Theobroma cacao L.) by-products for sustainable animal feed: an evaluation of polyphenol and antioxidant content

The EU Circular Economy Action Plan aims to reduce waste and optimize resources. Cocoa processing by-products, that are rich in polyphenols, methylxanthines, dietary fibers, and lipids, can be reused in animal feed, offering a sustainable solution. In this study, we evaluated the potential of cocoa processing by-products as a sustainable and valuable source of animal feed in line with the EU Circular Economy Action Plan. Cocoa bean shell samples (S1: flakes, S1K: chunky flakes, and S2: pellets) from a Swiss foodstuff processor were analysed using in vitro methods (Folin-Ciocalteu assay, DPPH assay, and vanillin test) and HPTLC. These methods assessed total polyphenol content, antioxidant capacity, and flavan-3-ols concentration. Sample S2 had the highest levels of phenolic compounds and flavan-3-ols. Samples S1 and S1K exhibited similar antioxidant activity, total polyphenols, and flavan-3-ols, although lower than S2. HPTLC analysis confirmed these findings. The physical form of the by-products (pellets vs. flakes) significantly influenced analyte concentration and antioxidant properties. Cocoa bean shells are a valuable source of polyphenols and flavan-3-ols with antioxidant properties, suitable for use as high-quality secondary raw materials in animal feed. Future potential formulations should also consider theobromine and caffeine content, to ensure compliance with EU guidelines (Directive 70/524/EEC and Directive 2002/32/EC) for animal safety and well-being.