ISOLATION AND CHARACTERIZATION OF PEPTIDES FROM MILK AS NATURAL INHIBITORS OF ACE I AND FOOD ADDITIVES

Inhibition of Angiotensin-converting enzyme I (ACE I) is a modern therapeutic approach to treatment of hypertension. In recent years, research into natural ACE peptide inhibitors without side effects has become important.The aim of this study is to isolate and characterize novel bioactive peptides from skim and/or whole cow’s milk fermented with selected lactobacillus strains. Several homo/heterofermentative strains of the Lactobacillus species of dairy origin have been pre-selected and different milk fermented samples have been studied. A protocol for analyses was designed and the milk proteins were separated by centrifugation at 4°C at 10000 × g, with molecular mass cut off (MWCO) membranes of 3 and 10 kDa. The samples with molecular mass below 3 kDa were further separated by ultrafiltration by dialysis cell (cut off membrane 1 kDa) by continuous stirring at room temperature. The milk fractions under 1 kDa molecular mass were characterized by UPLC-MS. The ACE-inhibitory activity was determined using the FAPGG (N-[3-(2-Furyl) acryloyl]-L-phenylalanyl-glycyl-glycine) degradation method. All tested samples (1 kDa) exhibit ACE I inhibitory activity with IC50 in a range of 6 - 37 mg mL-1. In silico logP prediction of selected peptides was used to assess whether lipophilicity of the compounds falls within the so-called “therapeutically relevant pharmacokinetic space”.