Proximate Composition, Amino Acid Profile, and Phytochemical Properties of African Yam Bean (Sphenostylis stenocarpa) and Fluted Pumpkin (Telfairia occidentalis) Seed Flours

Abstract

Underutilized seed flours from African yam bean (Sphenostylis stenocarpa) and fluted pumpkin (Telfairia occidentalis) were evaluated for proximate composition, amino acid profile, and phytochemical constituents. Significant variations (P < .05) were observed in proximate composition. Moisture content ranged from 5.45–7.32%, crude protein from 26.62–30.38%, crude fibre from 1.32–8.28%, fat from 1.45–34.56%, ash from 2.18–3.31%, and carbohydrate from 18.02–61.11%. Fluted pumpkin seed flour exhibited higher protein, fibre, lipid, and ash contents, whereas African yam bean showed higher moisture and carbohydrate levels. Both seed flours revealed the presence of essential and non-essential amino acids. Flour from fluted pumpkin contained higher levels of serine (8.60 g/100 g), proline (30.35 g/100 g), isoleucine (30.25 g/100 g), lysine (3.43 g/100 g), histidine (1.55 g/100 g), and tyrosine (3.95 g/100 g), whereas African yam bean seed flour recorded higher alanine (15.62 g/100 g) and valine (8.59 g/100 g). Glycine was detected only in African yam bean flour (11.86 g/100 g). Fluted pumpkin seed flour showed higher levels of bioactive compounds, including epicatechin (8.65 µg/g), quercetin (4.35 µg/g), gallocatechin-3-gallate (5.65 µg/g), and myricetin (3.45 µg/g), while African yam bean flour contained notable levels of genistein (1.22 µg/g), naringenin (2.00 µg/g), and artemetin (1.04 µg/g). Resveratrol and apigenin were detected only in fluted pumpkin seed flour. These results demonstrate that both seed flours possess valuable nutritional and phytochemical attributes, highlighting their potential as alternative plant protein sources and functional ingredients for food formulation.