Background: Soybean is an important protein crop for food and feed systems, but data on the biochemical composition and safety-related elemental profile of locally cultivated varieties in Burundi remain limited. The aim of the study was to evaluate protein content, amino acid composition and elemental profile of three soybean varieties widely grown in Burundi. 
 
Methods: Crude protein content was determined according to GOST 13496.4-2019. Amino acid composition and cationic and anionic composition were quantified by capillary electrophoresis. Selected trace and toxic elements were measured by inversion voltammetry using validated procedures. Amino acid score and biological value were calculated relative to the FAO/WHO reference protein. 
 
Result: Crude protein content ranged from 40.5 to 42.2%, with the highest value recorded in SOPROSOY. Essential amino acid profiles were similar among the studied varieties: lysine was 2.8%, valine 1.9-2.0%, phenylalanine 2.2-2.3%, leucine + isoleucine 5.1-5.3%, methionine 0.42-0.49%, threonine 1.8% and tryptophan 0.031-0.056%. Tryptophan was the first limiting amino acid, while methionine + cysteine also had reduced scores. Lead, cadmium, cobalt, selenium and iodine were below the method detection limits. Zinc reached 120&plusmn;50 mg/kg in SOPROSOY and exceeded the stated safety threshold. The studied varieties may be considered high-protein soybean raw materials; however, zinc accumulation requires monitoring when they are intended for food-oriented applications.

Biochemical Composition and Protein Quality of Three Soybean [Glycine max (L.) Merr.] Varieties Widely Grown in Burundi