Bioactive peptides from Italian sourdough: characterization of antioxidant and anti-inflammatory activities

Abstract: Degradation of cereal proteins in peptides during sourdough fermentation may have important repercussions on functional features of leavened baked goods. Protein degradation is due both to the acidification by lactic acid bacteria (LAB), which activate the flour proteases, and to the peptidases synthetized by this microbial population. Recent studies demonstrated the existence of peptides in sourdough that have a positive impact on human health (bioactive peptides). In particular, antioxidant peptides, that are able to prevent oxidative stress associated with numerous degenerative aging diseases (cancer and arteriosclerosis) and anti-inflammatory peptides. With the aim of identifying the LABs more effective in producing bioactive peptides, 131 different strains from Italian sourdoughs have been screened for peptidase activities. Among these, 23 strains were selected and singly inoculated in liquid sourdoughs from which a Low Molecular Weight fraction containing peptides was obtained. Characterization of the antioxidant and anti-inflammatory activity of the extracts has been performed on cultured cells by assaying ROS content, NF-kB/IkB expression level and IL-1β production. Four of the tested strains show high level antioxidant and anti-inflammatory activity, so we decided to characterize their peptides components using the modern mass spectrometry techniques. LAB able to release bioactive peptides could be used to develop starter cultures with functional features. As a result, four LAB strains have shown a high antioxidant and anti-inflammatory ability thus enabling the setting up of model sourdoughs to increase bread qualities.