Nutritional, phytochemical, and safety profiling of Senegalia seeds, promising wild legumes in the arid and semi-arid tropics

Abstract

This study presents the chemical composition of seven representative Senegalia (new Acacia s.l. segregate genus) seed species and discusses their food potential and safety. As shown, most of the analyzed seed species demonstrate unique chemical compositions, i.e., very low starch (<0.63 g/100 g dm (i.e., detection limit)) and glucose (1–2 g/100 g dm), high neutral detergent fibers (16–20 g/100 g dm), moderate protein (sum of amino acids) (10–20 g/100 g dm) and nucleic acid polymers (5.3–8.9 g/100 g dm), variable lipid (6–12 g/100 g dm), ash (3.3–4.9 g/100 g dm), phenolic compounds (741–1618 mg GAE/100 g dm), tannins (266–1230 mg TAE/100 g dm) and phytate (299–746 mg PAE/100 g dm) contents, and a relatively balanced amino acid composition. In addition, the seeds have revealed variable contents of trypsin inhibitors (18–45 TIU/mg dm), lectin-related proteins, unidentified non-protein amino acids, hemolytic activities, and cyanogenic glycosides (3.5–11.9 mg cyanide/100 g dm), contrasting their nutritional values and food safety. Despite the considerable effort to comprehensively and accurately determine the chemical composition of the seeds, a large mass fraction (37–44 g/100 g dm) remained unresolved, illustrating the challenge in unconventional food matrices analysis. Nevertheless, distinct compositional profiles between the seed species of the different Senegalia infrageneric sections (i.e., Senegalia section Senegalia and Senegalia section Monacanthea) were uncovered, inviting further investigation on the influence of the infrageneric segregation on the seed compositional properties and food safety.