Nutritional value, protein quality and antioxidant activity of Sudanese sorghum-based kissra bread fortified with bambara groundnut (Voandzeia subterranea) seed flour

Kissra, is traditionally prepared by fermenting sorghum seed flour and then baking it into bread sheets. In this study, bambara groundnut seed flour (BGF) was incorporated at 10%, 20% and 30% into kissra bread. Chemical composition, in vitro protein digestibility, protein quality, fatty acids and DPPH radical scavenging activity of fortified kissra were studied and compared with sorghum-based kissra (control). Protein, fat and energy of the control steadily increased (P < 0.05) with increasing percentages of BGF. All minerals (except for Mg and P) and all essential amino acids (except for Trp and Pro) increased significantly (P < 0.05) after fortification. Palmitic, stearic, oleic and linoleic acids were significantly improved. On the other hand, tannins, phytic acid and trypsin inhibitor activity were significantly reduced (P < 0.05). Protein quality of kissra improved with BGF fortification shown by improvement in the nutritional index, essential amino acid index, biological value, predicted protein efficiency ratio and the in vitro protein digestibility. Fortification increased significantly (P < 0.05) the total phenolics and total flavonoids and decreased the DPPH free radical scavenging activity. Overall, bambara groundnut flour could be used to upgrade the nutritional quality of cereal-based products. Keywords: Sorghum-based kissra, Bambara groundnut seed, Fortification, Nutritional quality, Antioxidant activity