Isolation and characterization of bioactive peptides produced by lactic acid bacteria.

Objectivo

This project aims at the isolation and identification of new bioactive peptides produced by lactic acid bacteria (LAB) with health promoting properties. To accomplish this target, the project will employ a wide range of methodologies targeted to select new LAB based on their ability to produce bacteriocins and biologically active peptides having hypotensive and/or angiotensin-I-converting enzyme (ACE)-inhibitory activity. In addition, we intend to evaluate the nutritive and health promoting potential of selected LAB strains by the production of CLA and GABA.

LAB strains will be initially screened for bacteriocins, GABA production and in vitro ACE-inhibitory activity. Bioactive peptides produced by LAB strains will be purified, characterized and identified by comparing their sequences with sequences of known bioactive peptides. With this approach we will gather knowledge on the structure of bioactive peptides produced by the LAB strains under study, having in mind the possibility of patent register.

To exert their health benefit, peptides with ACE-inhibitory activity must be bioavailable. For this reason, a simulated gastrointestinal digestion of bioactive peptides will be performed to confirm that the inhibitory activities generated during cheese fermentation are resistant to digestive enzymes encountered during transit.

The CLA production and immunostimulating activity of LAB will be determined to assess the effectiveness of nutritive and health promoting properties of new LAB strains in real cheese products. It is essential that LAB and bioactive peptides maintain their viability and efficiency during the manufacture and storage of the product. With this in mind, new LAB will be evaluated for its viability in cottage cheeses during their manufacture and refrigerated storage. Production of standard cottage cheese will be modified by the new LAB strains in pilot-scale studies. We expected to achieve a prolongation of shelf-life in resulting cheeses, together with improved nutritional and health promoting qualities.