Isolation and characterisation of angiotensin converting enzyme (ACE) inhibitory peptides in fermented milk of malabari goat

A study was conducted to isolate and characterise the angiotensin converting enzyme (ACE) inhibitory peptides from fermented milk of Malabari goat. Goat milk was fermented with seven different lactic acid bacterial cultures including Lactobacillus acidophilus (MTCC 10307), L. plantarum (NCDC 379), L. casei (NCDC 017), L. bulgaricus (NCDC 253), L. paracasei sub sp . paracasei (NCDC 022), L. rhamnosus (MTCC 8712) and L. helveticus (NCDC 192). These cultures were inoculated at 3 and 4% levels for the preparation of fermented milk. The pH, titratable acidity, lactic acid bacterial count, proteolytic activity and ACE inhibitory activity of the fermented milk ranged from 4.07 to 5.69, 0.36 to 1.24% lactic acid, 9.79 to 10.25 log cfu/ml, 0.32 to 0.69 and 67.56 to 97.55%, respectively. The highest ACE inhibitory activity was observed in milk fermented with L. plantarum (NCDC 379). Fermented milk with high ACE inhibitory activity were subjected to reverse phase high performance liquid chromatography to isolate the ACE inhibitory peptides. Characterisation of the peptides was done by Tris-tricine SDS-PAGE. The molecular weight of ACE inhibitory peptides was 1.4 kDa. It can be concluded that Malabari goat milk fermented with lactic acid bacteria is a rich source of ACE inhibitory peptides.