Valorization of Carapa guianensis By-Products: Extraction Optimization and Antimicrobial and Antioxidant Activity

Methods for extracting bioactive compounds are widely studied, as the global trend moves toward more efficient and eco-friendly methods. This study aimed to optimize and compare the extraction of phenolic compounds from the residual biomass of andiroba (Carapa guianensis) using the conventional method with methanol as the solvent, and a green chemistry method via ultrasound using ethanol as the solvent. The optimization of the extraction variables (time, mass/volume ratio, and ethanol concentration) was performed using a Central Composite Rotatable Design (CCRD 23) combined with the desirability function. The established optimal conditions were an extraction time of 26.78 min, a mass/volume ratio of 86.46 mg/mL, and an ethanol concentration of 32.5%. The conventional method achieved a higher yield of total phenolic compounds (TPC) (109.05 mg GAE/mL) and total flavonoid compounds (TFC) (38.18 mg GAE/mL) compared to the ultrasound-assisted method (UAE) (82.64 and 26.27 mg GAE/mL, respectively). LC-MS analysis revealed a diversity of extracted bioactive molecules. Both methodologies yielded extracts with good in vitro antioxidant activity (DPPH and ABTS). In the antimicrobial assay, the extracts demonstrated an unprecedented bacteriostatic effect for this residue, inhibiting the growth of the Gram-positive bacterium Staphylococcus aureus at concentrations ranging from 43.83% to 52.67%, with no activity against Gram-negative bacteria. The optimization demonstrated that the industrial residue of andiroba still contains a significant concentration of bioactive compounds. These findings confirm the bioeconomic potential of this by-product for the formulation of high-value-added bio-inputs, with promising applications in the development of smart packaging or bioactive food coatings.