Abstract
Yogurt is a nutritious dairy product, has established probiotics effects and may even be therapeutic for certain health conditions. Proteolytic activity of starter cultures during milk fermentation can be generating peptides with angiotensin-I converting enzyme (ACE- I; EC. 3.4.15.1) inhibitory activity. Effects of presence of Allium sativum or Cinnamomum verum on these peptides in yogurt were investigated. Two types of milk (cow and camel) were incubated (41 degrees C) with starter culture in the presence of A. sativum or C. verum water extract until pH of yogurt was reduced to 4.5. The resulting herbal- yogurts were evaluated with respect to changes of in vitro ACE- I inhibitory activity and proteolytic activity during 21 days of storage. In the present study, the extent of proteolysis was higher (p<0.05) in presence of A. sativum than presence of C. verum during storage with cow milk yogurt being more susceptible than camel-milk yogurt. The presence of A. sativum or C. verum increased ACE-I inhibitory activity more in cow- than camel- milk yogurt during storage. All herbal-yogurts showed the highest inhibitory activity of ACE-I (40%- 70%) on day 7 of storage. Prolonged storage of both types of yogurt to more two weeks decreased ACE-I inhibition activity (37% - 50%; p<0.05). In conclusion, A. sativum and C. verum can enhance yogurt functional properties with potential therapeutic values for hypertension.