EVALUATION OF THE PROTEIN FUNCTIONALITY OF COCOA SHELL DEFATTED USING ETHANOL AND ISOPROPANOL

Cocoa shell (CS) is a byproduct of the cocoa industry commonly underutilized as boiler fuel, however it has a significant content of lipids, proteins, fibers and biocompounds. The extraction of CS fat also generates the defatted solids (DS) with a high protein content, opening new perspectives of using this material. Thus, this work aimed to evaluate the effect of fat extraction on the functionality of the CS proteins, through of the nitrogen solubility index (NSI), water and oil absorption capacities (WAC and OAC) and foam forming capability (FFC) and stability (FS). The extractions were carried out using ethanol and isopropanol, in absolute and azeotropic degrees (ET0, ET6, IPA0 and IPA12), temperatures of 75 and 90 °C, mass ratio solid:solvent of 1:3, during the 3 hours. Protein content and NSI of CS and DS were determined by quantification of nitrogen through the combustion method. CS presented protein content of 17.1 ± 0.5% and maximum NSI around 50% at alkaline pHs. Protein contents, WAC and OAC in DS were higher than those of CS and the highest levels were obtained using IPA0 (19 ± 1%, 4.3 ± 0.2 g water/g solids and 2.3 ± 0.3 g oil/g solids, respectively), solvent that presents greater potential of fat extraction. The increase of the extraction temperature and the hydration of the solvents led to the reduction of NSI and FFC (maximum reduction of 88.9% and 73.8%, respectively), with higher values of FFC (30 ± 4%) and the best FSs obtained using absolute solvents at 75 °C. Based on the results, it can be inferred that the CS fat extraction process affects the functionality of DS, however, the use of alcoholic solvents without hydration at 75 °C causes a smaller impact, obtaining DS with good protein functionality and potential of application in food systems.