Introduction: Piacentinu Ennese (PE) is a Protected Designation of Origin (PDO) cheese produced using raw ewe’s milk without the addition of any starter culture. During the cheese-making saffron (Crocus sativus) and whole peppercorns are added and the final product is generally consumed as semi-hard (after 2-4 months of ripening) or hard (over 4 months of ripening) cheese types. Up to now, many spontaneously fermented dairy foods have been considered as reservoir of promising probiotic bacteria. Although a reasonable number of probiotic strains was already studied, it is of high relevance to screen for new ones with health benefits. To our knowledge, no previous studies were conducted in order to characterize the Lactobacillus population of PE cheese from the functional point of view. Materials and Methods: One hundred and sixty-nine LAB were isolated from 90 days ripened samples and identified using molecular fingerprinting and MALDI-TOF MS. One hundred and thirteen (113) isolates, included in the QPS-list, were screened, as recommended by the FAO/WHO, for both safety (DNAse; gelatinase; haemolytic and mucin degradation activities; biogenic amine production; antibiotic susceptibility and MIC determination; presence of genes encoding for virulence factors and antibiotic resistance) and functional properties (lysozyme, acidic and bile salts tolerances; survival during simulated gastrointestinal transit; antimicrobial activity; hydrophobicity, auto-aggregation, and co-aggregation abilities; adhesion to Caco-2 cells; antioxidant and anti-inflammatory activities). Results: Seven stains belonging to Lactobacillus rhamnosus and Lactobacillus paracasei species showed promising in vitro probiotic features. In fact, beyond the safety requirements and the ability to tolerate the harsh environmental conditions occurring during GIT passage, the selected strains showed a broad spectrum of antagonistic activity against both foodborne and intestinal pathogens. In addition, good potential to hinder oxidative stress and to inhibit the lipid peroxidation, which are believed to play a significant role in the development of tissue damage and in several human pathologies, was achieved. The study of the gene expression of inflammatory pathways, using an in vitro model consisting of human macrophages exposed to LPS, underlined the ability of the selected stains to reduce the inflammatory cytokine IL8 and to increase the anti-inflammatory cytokine IL10. Moreover, having inhibitory activity of cyclooxygenase, the selected strains were also skilled in regulating the expression of cytokines helping to reduce the recruitment of immune organism cells. Conclusions: The present study revealed that Piacentinu Ennese PDO is a good source of L. rhamnosus and L. paracasei strains with in vitro promising probiotic properties.
|Titolo:||Selection of promising probiotic strains isolated from Piacentinu Ennese PDO cheese|
PINO, ALESSANDRA (Corresponding)
|Data di pubblicazione:||2019|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|