Evaluation of morphological diversity, nutritional potential, and techno-functional properties of improved soybean ( <i>Glycine max</i> (L.) Merr.) accessions and varieties cultivated in Niger

Food insecurity and malnutrition remain major challenges in Niger, where protein-rich crops are critically needed. Soybean (Glycine max (L.) Merr.) is recognized as a strategic legume due to its high protein content (typically 35–45%) and valuable techno-functional properties reported in the literature. However, local accessions and improved soybean varieties cultivated in Niger remain poorly characterized in terms of their nutritional and techno-functional potential. This study aimed to comparatively evaluate the morphological traits, nutritional composition, and techno-functional properties of 12 local soybean accessions and 3 improved varieties cultivated in different agro-ecological zones of Niger. Samples were analyzed in triplicate using standard gravimetric, potentiometric, and functional property assessment methods. Protein contents ranged from 35.89 ± 0.26% to 40.58 ± 1.25%, values comparable to or slightly lower than those reported for improved soybean cultivars worldwide (≈40–45%). Lipid contents varied from 9.83 ± 1.07% to 18.47 ± 1.27%. Water absorption capacity ranged from 187.01 ± 2.51% to 289.00 ± 9.31%, while oil absorption capacity varied from 125.40 ± 5.90% to 175.87 ± 0.13%, indicating good functional performance relative to reference legume flours. Solubility reached up to 48.80%, particularly for accession AC34 (Tara), whereas swelling power remained modest (4.11–6.68 g/g). These results highlight the nutritional and techno-functional potential of both local accessions and improved soybean varieties, supporting their use in food formulation and their valorization as a strategy to enhance food and nutritional security in Niger.