Biscuits were produced from sorghum with and without the addition of sourdough. The influence of sourdough fermentation on the amino acids composition, phenolic profile, and antioxidant properties of the biscuits were evaluated. Phenolic compounds of the biscuits were identified and quantified using gas chromatography/mass spectrometer. The total phenol contents (TPC), total flavonoid contents (TFC), ferric reducing antioxidant properties (FRAP), 2,2'-azinobis( 3-ethylbenzothiazoline-6-sulphonic) (ABTS) scavenging ability, 1,1-diphenyl-2-picryl-hydrazy (DPPH) scavenging ability, and nitric oxide (NO) scavenging ability of the biscuits were determined. Addition of sourdough increased the total essential amino acids, total non essential amino acids, hydrophobic, and aromatic amino acids contents of the biscuits. Essential amino acid index, biological value, and predicted protein efficiency were higher in biscuits with sourdough than in biscuits without sourdough. Six phenolic compounds were identified and quantified in the biscuits. Ferulic acid was the most prominent phenolic compound, followed by chlorogenic acid. TPC, TFC, FRAP, ABTS, DPPH, and NO scavenging abilities increased significantly with the addition of sourdough. Sorghum biscuits with sourdough could be useful in dietary interventions to prevent protein-energy malnutrition. Similarly, the presence of bioactive phenolic compounds and their antioxidant efficacy suggest health benefits in the management of oxidative stress and degenerative diseases.
Keywords: amino acids; antioxidant properties; biscuits; phenolic profile; sourdough.