Extrusion-driven metabolic shifts in composite flour from coffee and plantain byproducts

Abstract

This study outlines the effects of extrusion on the metabolomic profile and functional properties of composite flour produced from coffee pulp, plantain rachis, and rejected plantain. Metabolomic analysis using liquid chromatography–mass spectrometry and gas chromatography–mass spectrometry revealed that 124 metabolites showing differential abundance between nonextruded flours (NEF) and extruded flours (EF). Of these, 83% (103 metabolites) decreased and 17% increased after extrusion. Global trends revealed decreases in carbohydrates, glycerophospholipids, organic acids, flavonoids, and quinic acid derivatives, whereas amino acids and alkaloids displayed mixed responses. In terms of phenolic compounds, extrusion reduced the contents of several compounds, such as procyanidins, catechins, and chlorogenic acids, but markedly increased the content of quercetin. These changes represent an increase in total phenolic content (from 5.38 ± 0.60 to 7.92 ± 1.00 mg GAE g⁻¹, dry basis) and antioxidant activity (from 50.82 ± 3.44% to 72.62 ± 5.87%). A slight reduction in crude protein was observed; however, protein bioavailability significantly improved with thermomechanical processing. Overall, extrusion modified the metabolomic profile of the composite flour and improved its functional and nutritional attributes, highlighting the relevance of this technology for producing precooked flour from byproducts as a promising ingredient for the production of value-added and sustainable foods.