Euterpe oleracea Mart. (açaí) seeds show in vitro prebiotic potential: Integrative evidence from human colonic fermentation.

Açaí seeds (Euterpe oleracea Mart.) are an abundant agro-industrial by-product rich in bioactive compounds, remain unexplored for their gut microbiota modulating potential. This study investigated the modulation of gut microbiota composition and metabolism by discarded açaí seeds using an in vitro colonic fermentation model. The seeds were characterized by a high insoluble fiber (70.40 g/100 g), and mannose as the major monosaccharide. Colonic fermentation with discarded açaí seeds (AS48) preserved microbial diversity relative to the fermentation control (CT48) and was associated with higher abundance of beneficial genera, including Akkermansia and Phascolarctobacterium, alongside a reduced abundance of Escherichia-Shigella. Multivariate analysis of short-chain fatty acids (SCFAs), metabolomic, and volatilomic profiles revealed a consistent and coherent cluster for AS48 samples, separated from both the CT0 and the fermentation control (CT48). Metabolomic analysis revealed higher levels of propionate and a more balanced acetate-to-propionate ratio in AS48, while γ-aminobutyric acid (GABA) was less depleted than in CT48. Odd-chain fatty acids were detected exclusively in AS48. The volatilomic profile showed a favorable shift from phenol to indole, with exclusive detection of organosulfur compounds. A refined Partial Least Squares-Discriminant Analysis (41 metabolites, seven genera) validated treatment discrimination, with Spearman correlations linking Phascolarctobacterium to propionate and indole, and Akkermansia to pentadecanoic and pipecolic acids, metabolites exclusive to AS48. These findings suggest that discarded açaí seeds may exhibit prebiotic potential under the tested in vitro conditions, acting on gut microbial metabolism to yield distinct outputs and supporting their valorization as a promising functional ingredient with added value.