Separation of the Lipid Fraction from Cocoa Bean Husks Using Ethyl Acetate as Solvent in Ultrasound-Assisted Process

This study aimed to obtain the lipid fraction from cocoa bean husks by applying ethyl acetate as an extraction solvent in an ultrasound-assisted extraction process. The effects of temperature (T), time (t), and solvent:husk ratio (R) on the lipid fraction (LF) yield were evaluated. The removal of minor compounds (phytosterols and tocopherols) and total phenolics was evaluated under selected conditions, as well as the value of conjugated dienes (CDs). Extraction with n-hexane was performed for comparative purposes. The prediction of the solubility of the main compounds identified in the solvents used was conducted. The influence of the variables on LF removal was T > t > R, which provided the highest result (13.54 ± 0.47 wt%) at the highest levels adopted (70 °C, 60 min, 12 g/mL), a value 23% higher than that obtained using n-hexane. Under these conditions, there is also greater recovery of minor compounds from the peels, especially β-sitosterol, which was quantified at 43 to 50% of the concentration of these compounds. The use of ethyl acetate provided greater removal of minor compounds and total phenolics, resulting in lower primary lipid oxidation products (CD value). The relationship between these properties was evidenced by the Pearson correlation matrix, especially for stigmasterol, campesterol, total phenolics, and total minor compounds. The thermodynamic modeling reveals regimes ranging from full miscibility of liquid solutes to limited solubility of phytosterols and gallic acid; however, the contrast with experimental data indicates that real extraction is limited by kinetic barriers and plant matrix effects. The solvent extractor did not influence the fatty acid profile of the LF obtained, consisting mainly of saturated fatty acids (palmitic and stearic).