Extraction of bioactive compounds from nacional variety cocoa shell (Theobroma Cacao L.) obtained using supercritical CO2

Nacional, also known as Fino de Aroma or Arriba, is an ancient and rare variety of cocoa highly demanded by chocolate manufacturers because it is used to produce the finest chocolates in the world. Notably, chocolate manufacturing produces residues which may contain valuable bioactive compounds. To identify these bioactive compounds, we herein report their extraction from National variety cocoa shell by applying both conventional and non-conventional extraction techniques.  Cocoa shell is the raw material for extraction, and it was characterized by analyzing its physicochemical properties, such as moisture, fat, ash, total fiber, total protein, and total carbohydrates. Extraction by the conventional Soxhlet technique and maceration used methanol as solvent. Supercritical CO2 and supercritical CO2 with methanol as a cosolvent were used as the non-conventional extraction techniques with a pressure range of 20 – 25 MPa and temperatures of 35 – 60 °C. Global Yield of extraction (Y%) and antioxidant activity were evaluated for all conditions and techniques. The primary components of cocoa shell byproduct were fiber, protein, ash, and fat at 58.4%, 18.5%, 13.2% and 9.05%, respectively. The highest Y% was obtained for the maceration technique (7.91 ± 0.01%), while the Soxhlet technique produced a lower Y% (6.20 ± 0.01 %). The Y% of supercritical fluid extraction (SFE) with CO2 ranged between 4.18 ± 0.05% and 4.41 ± 0.01%. When methanol was used as cosolvent, Y% increased to 5.81 ± 0.01 %. The antioxidant activity of extracts varied from 7.21 ± 22.4 to 15.50 ± 22.4 µmol TEAC g-1, and the highest values were obtained from the maceration process. The results demonstrate that cocoa shell can be used as a potential ingredient for functional foods owing to its high content of beneficial compounds like dietary fiber, polyphenols, and other bioactive molecules.