Physicochemical determinants and mechanisms of the hard‐to‐cook problem of Senegalia seeds, overlooked wild legumes in the arid tropics

Abstract

SummaryThis study was carried out to elucidate the factors responsible for the hard‐to‐cook problem of Senegalia seeds, overlooked wild legumes in the arid tropics. Accordingly, they were identified as medium size (diameter = 7–9 mm and weight = 60–100 mg), flattened (thickness = 1.5–2.5 mm), and wax‐coated seeds, demonstrating high and variable coat fractions (25–41), mucilage (15–39), lignin (2.2–4.9), cellulose (6.7–13), and hemicellulose (1.9–5.6) contents (g/100 g dry weight), cooking times (3–5 h), and hydration properties. The hard‐to‐cook problem was primarily associated with the seed coats' microstructures and chemical compositions (i.e., cellular layers and fibre compositions). Besides, sodium bicarbonate (common cooking aid) helped half the cooking times but failed to overcome the toughness of the seed coats. Furthermore, unfortunately, there was no clear association between the seeds' cooking properties and phylogenetic lineages, indicating that each species should be assessed individually. This work provides unprecedented insights that will considerably assist in selecting, formulating, and promoting food products from Senegalia seeds.