The aim of the present study was to investigate antioxidant, angiotensin converting enzyme (ACE) inhibitory, and anti-microbial activities of wheat wafers enriched with 1%, 2%, or 3% (w/w) of millet flour (M1, M2, or M3, respectively). All samples were characterized by a richer composition of protein, polyphenols, flavonoids, phenolic acids, and reducing sugar in comparison with the control sample. The highest content of the components, i.e., 1.03 mg mL-1, 0.021 mg mL-1, 2.26 mg mL-1, 0.17 µg mL-1, and 0.63 mg mL-1, respectively, was detected in sample M3. The same sample was characterized by 803.91 and 42.79% of water and oil absorption capacity, respectively. The additive did not change the rheological features of the wafers. The 3% addition of millet flour to the wafer formulation induced the highest antioxidant activity against DPPH, Fe2+ chelation, and ACE inhibitory activity of hydrolysates (IC50 = 191.04, 0.46, and 157.73 µg mL-1, respectively). The highest activities were determined in the M3 fraction <3.0 kDa (IC50 = 3.46, 0.26, and 16.27 µg mL, respectively). In turn, the M2 fraction was characterized by the highest antimicrobial activity against Listeria monocytogenes with a minimum inhibitory concentration (MIC) value of 75 µg mL-1.
Keywords: antioxidant; biological compounds; millet flour; rheological properties; wafers.