Physicochemical profiling of Bambara groundnut (Vigna subterranea L.) reveals variation in cooking quality relevant to breeding programs

Understanding seed physicochemical properties allows breeders to select traits that contribute to desirable cooking characteristics (texture, taste, and nutritional content). Breeding programs can optimize resources by focusing on traits directly related to cooking time and quality. A total of 156 Bambara groundnut (BGN) recombinant inbred lines were analysed for physicochemical properties [hydration capacity (HC), hydration index (HI), swelling index (SI), pH, texture and cooking time (CT)], proximate and nutrient compositions. Analysis of variance showed significant differences (p < 0.05) in variables measured. Shortest CT (40 min) was recorded in S19/Ankpa4-100-87, while S19/Ankpa4-106-92 has the longest CT (147 min). Cooking time was negatively correlated with HC (r = - 0.42), HI (r = - 0.45) and swelling capacity (SC) (r = - 0.55). Neutral Detergent Fibre (NDF) and protein content showed significant differences between raw and cooked BGN (p < 0.05). Cooking significantly increased protein, fat, NDF, Zn, and Cu; however, cooking also significantly reduced Fe and total mineral (ash). Texture, CT and electrical conductivity (EC) of the genotypes varied significantly, which aided classification into five groups, namely: A (soft-cooking genotypes), B (slightly soft-cooking genotypes), C (slightly hard-cooking genotypes), D (moderately hard-cooking genotypes) and E (hard-cooking genotypes). A total of 14 genotypes (DodR, BURKINA, ANKPA 4, TIGD, NAV 4, S19/Ankpa4-100-87 IITA686/LunT-292-233, IITA686/LunT, S19/Ankpa4-130-1, S19/Ankpa4-50-43, S19/Ankpa4-92, IITA686/LunT-403-314, S19/Ankpa4-141-121 and S19/Ankpa4-234-197) were grouped as soft-cooking. These soft-cooking genotypes could be available as genetic stock to confirm this attribute or reanalysis by breeders.