Proteolytic activity, antioxidant, and α-Amylase inhibitory activity of yogurt enriched with coriander and cumin seeds

Two types of yogurt (Y) were prepared in the presence of coriander (CO) or cumin seeds (CS) at different concentrations (5, 10, 15, & 20 g/100 mL). The effect of these yogurt samples on post-acidification, proteolysis, a-amylase inhibition activity, total phenolic content, and antioxidant activity (2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant potential (FRAP), and ferrous ion chelating (FIC) ability) was studied during 0,7, and 14 days of refrigerated storage at 4 degrees C. In addition, sensory evaluation of the yogurt was run during the first day of storage. Both COY and CSY at all concentrations showed significant effects on post-acidification, peptide content, and alpha-amylase inhibition activity as compared to plain yogurt (control). TPC in COY at all concentrations (42.4-165.4 mu g GAE/mL) was higher than in CSY (39.0-75.7 mu g GAE/mL) during the entire storage period. The radical scavenging activity increased (p < 0.05) in COY at 20, 15, and 10 g/100 mL concentrations (94 +/- 0.01%, 93 +/- 0.01%, and 89 +/- 0.03%; respectively) on 7 days of storage. FRAP values were higher in CSY at all concentrations than COY during 7 days of storage. Higher (p < 0.05) FIC ability was observed in both types of yogurt than control. The highest overall preference score was shown at a concentration of 15 g/100 mL for both types of yogurt. In conclusion, COY and CSY at all concentrations positively enhanced natural yogurt ability to inhibit alpha-amylase activity with high antioxidant activity.