Neltuma nigra cotyledon and seed flour: nutritional, phytochemical, and techno-functional characterization and nutraceutic potential of polyphenolic enriched extract

Abstract

Neltuma nigra seed and cotyledon flours were prepared and characterized. Both flours showed high protein and fiber content, and low carbohydrate and fat content. The major storage proteins in N. nigra flours were albumin and globulin. In addition, flours contained carotenoids and potassium as the main micronutrients. The free and bound phenolic compounds, tannins and flavonoids were the major phytochemical components. The phenolic enriched extracts (PEE) of both flours contained apigenin-derived C-glycosyl flavones, including schaftoside, and isoschaftoside as the main components. The PEE from seed flour contained higher antioxidant capacity on ABTS˙⁺, FRAP, H₂O₂, O₂˙⁻ and higher inhibitory effect on α-amylase and α-glucosidase than the cotyledon flour extract. Techno-functional property analyses showed better water retention capacity and emulsifying stability for cotyledon flour and better oil holding capacity and emulsifying activity for seed flour. The results suggest better biological properties and a low-cost accessibility of seed flour, and a better macronutrient balance for cotyledon flour. Therefore, both can be considered as ingredients or functional food for special foods related to the metabolic syndrome and diseases related to oxidative processes.