Valorization of Amazonian açaí agro-industrial residues through functional flour production: a circular-economy approach for sustainable applications

Abstract Açaí ( Euterpe oleracea Mart.) is a fruit native to the Amazon region and, owing to its health-promoting properties, has been recognized as a “superfruit”. The açaí seed, obtained after the depulping process, represents approximately 90% of the fruit weight and, when improperly discarded, may cause environmental impacts. However, this residue shows nutritional, functional, and technological potential. This study aimed to characterize açaí seed flour by evaluating its physicochemical, functional, and structural properties, providing a comprehensive understanding of its composition and potential sustainable applications. Such knowledge reinforces resource recovery and circular-economy practices. The açaí seed flour presented a carbohydrate content of 90.2 g/100 g, a protein content of 4.5 g/100 g, and a lipid content of 4.0 g/100 g (dry basis). Among the fatty acids, myristic (26.5%), oleic (19.8%), and linoleic (19.1%) acids predominated. Mineral analysis revealed potassium (380.45 mg/100 g), phosphorus (130.41 mg/100 g), and magnesium (42.14 mg/100 g) as the main elements. In terms of functional properties, phenolic profiling revealed relevant levels of flavanols (epigallocatechin gallate, 328.27 mg/kg; epicatechin, 128.88 mg/kg), proanthocyanidins (procyanidin B2, 41.51 mg/kg; B1, 30.91 mg/kg), and flavanones (naringenin, 27.43 mg/kg). In addition, the flour exhibited high antioxidant activity, with approximately 90% scavenging activity of DPPH and ABTS radicals. Thus, the results highlight the nutritional and bioactive potential of açaí seed flour as a functional food ingredient and support its valorization as a sustainable alternative that adds value to the açaí production chain.