COMPUTATIONAL SCREENING OF DEEP EUTECTIC SOLVENTS AND BIOBASED SOLVENTS FOR PHENOLIC EXTRACTION FROM DEFATTED BRAZIL NUT CAKE

Brazil nut cake (Bertholletia excelsa), a residual by-product of oil extraction, presents high potential as a source of phenolic compounds and selenium, both of which are of considerable nutritional and technological relevance. This study aimed to evaluate emerging green solvents, including Deep Eutectic Solvents (DES) and Biobased Solvents, for the extraction and quantification of these compounds, with the goal of adding value to the Brazil nut production chain and promoting environmentally safe alternatives for recovery of bioactive compounds. The raw material was obtained from COOPAVAM (Juruena-MT) and transported to the laboratory, where it was freeze-dried, characterized for moisture (2.7 g/100 g), lipids (12.3 g/100 g), and proteins (34.7 g/100 g), and stored in an ultra-freezer at –80 °C. For solvent selection, a computational screening was performed using the COSMO-SAC model, evaluating 500 DES combinations and 50 Biobased Solvents based on their interaction with model molecules such as carboxylic acids, sugars, and polyols, all recognized as safe by the Food and Drug Administration (FDA). Based on the results of the activity coefficient at infinite dilution, systems containing hydrogen bond acceptors (HBAs), e.g., choline chloride ([Ch]Cl) and betaine, combined with different hydrogen bond donors (HBDs), e.g., glycerol, lactic acid, and acetic acid, as well as biobased mixtures with ethanol or water, were selected. An ultra-performance liquid chromatography method coupled with mass spectrometry (UPLC-MS) was developed to investigate the phenolic composition of Brazil nut cake. For method validation, hydroalcoholic extracts prepared with ethanol (70%) and methanol (70%) were analyzed, enabling the identification and quantification of 16 phenolic compounds using calibration curves with external standards. The main compounds detected in these extracts were procyanidin B1 (3.67–3.77 µg/mL), procyanidin B2 (2.19–3.56 µg/mL), and catechin (~1.1 µg/mL), along with syringic, protocatechuic, and gallic acids in lower concentrations. The higher abundance of procyanidins reinforces the antioxidant potential of the cake, in agreement with previous studies, although with different contents due to the efficiency of oil extraction and raw material composition. Computational results showed that solvents containing choline chloride, betaine, and hydroxylated compounds presented greater affinity for phenolics, making them promising candidates for further optimization studies. It can be concluded that Brazil nut cake is a viable source of phenolic compounds, particularly procyanidins, and that computational screening combined with experimental validation provides a solid foundation for future research on the application of green solvents.