In this study, the in vitro ACE-inhibitory activity of functional yoghurt produced normal yoghurt culture mixed with Lactococcus lactis DIBCA2, was compared to the control yoghurt. Two sets of yoghurt were produced using reconstituted skim milk(12% w/w): one type was produced using Lactobacillus bulgaricus and Streptococcus thermophilus (current yoghurt culture), another type was prepared using Lactococcus lactis DIBCA2 in addition to yoghurt culture. Viability, proteolytic activity, pH, physicochemical properties of both batchs of yoghurt were also assessed during 21 days of storage at 4 . Results showed that the presence of Lactococcus lactis DIBCA2 reduced feremention time and enhanced the growth of Streptococcus thermophilus in functional samples. The peptide content and proteolytic activity of functional yoghurt were higher than control samples throughout storage. Thus higher levels of essential amino acids and peptides in functional yoghurt may have promoted the growth of Streptococcus thermophilus. The use of selective strain as adjunct culture in yoghurt results in remarkable increase in vitro ACE-I activity compared to the control yoghurt. The IC 50 value of 1.02±0.11 mg/mL for functional samples was obtained. Key words : Hypertension, functional food, bioactive peptides, ACE-inhibitory activity, proteolysis.
