Comparative Valorization of Amazonian Fruit Wastes Reveals Açaí Seeds as a Promising Source of Antibacterial and Antioxidant Compounds.

Evaluation of the biological activity of food wastes is essential to identify promising bioactive compound sources for food applications. This study comparatively analyzed bioactive compounds and biological activities of Amazonian agro-industrial fruit wastes: acerola pomace (AP), açaí seed (AS), mango peel (MP), and pupunha peel (PP), aiming at their valorization as natural antioxidants and antimicrobials. Extracts were obtained by dynamic maceration using ethanol and methanol, and thermal treatment using water and diluted sulfuric acid at mass/solvent ratios of 1:10 and 1:20 (w/v). Total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (AA), and major phenolic compound profile by HPLC-DAD were determined. Antibacterial activity was assessed by broth microdilution. Extracts showing antimicrobial potential were further evaluated for cytogenetic safety using the Allium cepa assay. Ethanolic and methanolic AS extracts (ASE and ASM) at 1:10 (w/v) showed the highest TPC (2,252.20 and 2240.00 mg GAE/100 g, respectively). ASM showed the highest TFC (1112.31 mg/100 g), while ASE showed the highest AA (25661.90 µmol TE/100 g). Catechin was the predominant phenolic compound in ASE 1:10 (29.86 ± 0.64 mg/100 g). Only ASE and ASM showed antibacterial activity, with bactericidal effects against Staphylococcus aureus and bacteriostatic activity against Proteus mirabilis and Pseudomonas aeruginosa. ASM exhibited genotoxic and mitodepressive effects, whereas ASE demonstrated the lowest cytogenetic alterations at the bactericidal concentration. ASE represents a promising renewable source of bioactive compounds for high-value products, supporting sustainable waste management. PRACTICAL APPLICATIONS: Amazonian fruit residue extracts, especially those obtained from açaí seeds, showed potential as sustainable sources of natural antioxidant and antibacterial compounds. The ethanolic açaí seed extract may be explored as a functional ingredient or natural additive in food products, contributing to cleaner-label formulations, improved oxidative stability, and extended shelf life. This study also highlights the importance of selecting extraction methods that combine bioactivity with biological safety for future food applications.