Roasting-Induced Changes in Bioactive Compounds and Volatile Profile of Açaı´ (Euterpe oleracea) Seeds Powder Assessed by Response Surface Methodology and Principal Components Analysis

Abstract

Te aça´ı palm (Euterpe oleracea Mart.) is valued for its pulp, yet 85% of the fruit—the seed—is discarded, raising environmental concerns. In Northern Brazil, roasted seeds are consumed as a cofee-like beverage, but the impact of roasting on their composition remains unclear. Tis study evaluated how roasting afects the physicochemical, bioactive, and volatile profles of aça´ı seeds, using multivariate analysis to relate processing conditions with bioactive retention and aroma development. Aça´ı seeds obtained from Afua, Par ´ a, Brazil, were dried and roasted in a rotary roaster under a central composite rotational design ´(165°C–235°C; 8–22 min). Roasted seeds were then ground for analysis. Proximate composition, physicochemical properties, minerals, phenolics, antioxidant capacity, inulin content, and volatile profle were evaluated. Roasting efects were modeled by ANOVA and response surface methodology, while principal components analysis assessed volatile distribution. Raw aça´ı seeds showed a fbrous and porous structure with high fber (84.25 g/100 g), phenolics (37.07 mg GAE/g), inulin (16.05 g/100 g), and notable minerals content, particularly potassium. During roasting, soluble solids were peaked at mild conditions (175°C/10–20 min), while higher temperatures reduced moisture, pH, phenolics, antioxidant capacity, and inulin, highlighting temperature as the main factor, while color change was intensifed with both time and temperature. Optimal phenolic retention was predicted at 174°C/16 min, and the volatile analysis revealed shifts from oxygenated compounds (aldehydes and terpenes) under mild roasting to Maillard-derived products (furans, pyrazines, and phenolics) at higher intensities. PCA explained 77.1% of variance, clearly separating light roasts with fresh notes from darker roasts with caramelized and nutty attributes. Roasting allows for the modulation of their profle, as milder conditions preserve prebiotics and antioxidants, while higher temperatures develop desirable roasted aromas. Tis enables the tailoring of ingredients for food applications, adding value to this by-product.