Lactic acid bacteria as producers of peptides with biological activities

HEBERT, E.M.; FERRANTI, P.; SAVOY DE GIORI, G.

San Miguel de Tucumán

Simposio; II Simposio Internacional de Bacterias Lácticas, Primer Encuentro Red BAL (Bacterias Lácticas); 2006

CERELA-CONICET

Fermented milks exhibit a range of beneficial properties for human health, affecting the cardiovascular, endocrine, immune and nervous systems, in addition to nutrient utilization. One potential mechanism for explaining these beneficial effects could be mediated through the generation of biological active peptides, which are released from milk proteins by the proteolytic system of lactic acid bacteria (LAB). In this manner, bioactive peptides are directly released into a food, requiring no further purification or processing. Among the different groups of bioactive peptides, angiotensin converting enzyme (ACE)-inhibitory peptides are receiving special attention due to their potential antihypertensive effects. We have characterized the cell envelope-associated proteinase of Lactobacillus helveticus and Lactobacillus delbrueckii subsp. lactis strains responsible for releasing of biologically active peptides from a-casein and â-casein. Some of these casein hydrolysates showed inhibitory activity towards ACE in vitro. Several peptides were fractionated by reversed phase high pressure liquid chromatography and identified by mass spectrometry. The proteolytic enzymes of LAB are not very specific and a great variety of peptides are released from casein during fermentation. Exploitation of the biodiversity of the proteolytic system of LAB could be a promising alternative of directly producing natural bioactive peptides in fermented milk products for improvement the treatment or prevention of hypertension.