Enhancing the Extraction of Phenolic Antioxidants from Amazonian Assai (Euterpe oleracea Martius) Fruit Waste through Response Surface Methodology Optimization

Assai (Euterpe oleracea Martius) is a superfruit widely consumed in several countries, mainly produced in the Amazon region. The significant growth of the market for this fruit has raised environmental concerns regarding the disposal of production waste, especially the seeds that are not utilized and represent approximately 80% of the fruit. In the present study, strategies were developed for transforming these seed wastes into new products, using green solvents for extraction under conditions conducive to technology transfer and with feasible quality control through simple bench techniques, which represents an ideal approach for establishing a truly sustainable process. A significant interaction between solvent and extraction method was observed, impacting both yields and total phenols. Phenolic compounds are substances known for their health benefits, functioning as antioxidants and consequently aiding in disease prevention. The phenolic content observed in the extractions increased from 22.68% to 44.74% under optimal conditions during extraction via hot maceration (50 °C) in 100% ethanol for 2 h, which also enhanced yield and increased antioxidant capacity. The extracts displayed remarkable free radical scavenging activities (IC50 = 6.54 μg/mL in ABTS and IC50 = 14.71 μg/mL in DPPH), approaching the Trolox and quercetin standards, respectively. The optimized method paved the way for the industrial-scale utilization of the residues of this valuable Amazonian fruit.