BRAZIL NUT PRESS CAKE EXTRACTS RICH IN LIPIDIC BIOACTIVES AND POLYPHENOLS USING GREEN SOLVENTS BASED ON DL-MENTHOL AND ETHANOL

Native to the Amazon, the Brazil nut (Bertholletia excelsa HBK) is a key economic resource with a high lipid content (~70%). Industrial oil extraction via cold pressing yields a semi-defatted press cake residue which, despite the process, retains roughly 45% lipids. This byproduct is a rich source of valuable nutraceuticals like tocopherols and phytosterols, suitable for solvent-based recovery. In this context, Terpenic Eutectic Solvents (TES) have emerged as promising sustainable alternatives for the extraction of such hydrophobic compounds. This study evaluated, via thermodynamic computational simulation, the potential of these solvents combined with ethanol for extracting major and minor lipids, as well as antioxidants, with subsequent experimental validation. Solvent screening was performed using COSMO-SAC to predict sigma profiles and infinite dilution activity coefficients for key target solutes: POLi, OOLi, γ-tocopherol, β-sitosterol and gallic acid. The extraction systems comprised binary blends of DL-menthol with either acetic or lactic acid, evaluated both with and without ethanol (60–95% mol) at 60°C, using pure ethanol as a benchmark. Following the simulation-based optimization, the selected solvents were applied to the experimental extraction of antioxidants from Brazil nut press-cake (1:4 solid-to-solvent ratio, 200 rpm, 60 °C, 4 h). Evaluation parameters included total lipid, polyphenol, and phytosterol contents; fatty acid and tocopherol profiles; lipid composition (MAG, DAG, and TAG); and DPPH scavenging activity (IC₅₀). Extraction yield and distribution coefficients were determined, and the morphology of the spent solids was analyzed via Scanning Electron Microscopy (SEM). Statistical significance was assessed using ANOVA followed by Tukey’s test (p < 0.05). The analysis showed that adding TES to ethanol enhances extraction of phytosterols, tocopherols, and polar antioxidants. Such changes in solubility profiles suggest that DL-menthol-based blends serve as strategic solvents for tailored extraction, surpassing the performance of pure ethanol regarding selectivity for high-value compounds. Overall, these findings demonstrate that DL-menthol-based TES are superior alternatives to pure ethanol for the targeted recovery of high-value minor components, offering a sustainable pathway for the valorization of Amazonian industrial byproducts.

Acknowledgments: CNPq, CAPES, and FAPESP