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Technicien(ne)
Faculté des Sciences et Technologies - Nancy
Université de Lorraine
+33 (0)3 72 74 51 94 | chantal.poirson@univ-lorraine.fr
International Dairy Journal, 56, pp. 159-168.
El Hatmi, H., Jrad, Z., Khorchani, T., Jardin, J., Poirson, C., Perrin, C., Cakir-Kiefer, C., Girardet, J.-M.
Camel milk was fermented by Streptococcus thermophilus LMD-9 strain, the proteolytic system of which yielded peptides from the milk proteins. The peptides were isolated by cation-exchange chromatography and ultrafiltration, and then separated into 9 fractions by reversed-phase high-performance liquid chromatography. Two fractions displayed efficient radical-scavenging properties shown by Trolox equivalent antioxidant capacity assay. At least 347 peptides distributed in the different fractions were identified by tandem mass spectrometry. They mainly derived from the four different caseins, glycosylation-dependent cell adhesion molecule-1 (GlyCAM-1), also called lactophorin, and peptidoglycan recognition protein-1. For the first time, cleavage sites were identified for these six proteins and the susceptibility of GlyCAM-1 towards bacterial proteolysis directly in milk was shown. Investigation of peptide sequences homologous to known bioactive peptides highlighted not less than 16 different putative biological activities. Fermentation of camel milk was thus a means of food processing to produce potential bioactive peptides.
Food Microbiology, 53 (A), pp. 18-29.
Uriot, O., Galia, W., Awussi, A. A., Perrin, C., Denis, S., Chalancon, S., Lorson, É., Poirson, C., Junjua, M., Le Roux, Y., Alric, M., Dary, A., Blanquet-Diot, S., Roussel, Y.
Streptococcus thermophilus, a lactic acid bacterium used to produce yogurts and cheeses is more and more considered for its potential probiotic properties. This implies that additional information should be obtained regarding its survival and metabolic activity in the human Gastro-Intestinal Tract (GIT). In this study, we screened 30 S. thermophilus strains for urease, small heat shock protein, and amino-acid decarboxylase functions which may play a role in survival in the upper part of the GIT. The survival kinetics of 4 strains was investigated using the TIM, a physiologically relevant in vitro dynamic gastric and small intestinal model. The three strains LMD9, PB18O and EBLST20 showed significantly higher survival than CNRZ21 in all digestive compartments of the TIM, which may be related to the presence of urease and heat shock protein functions. When LMD9 bacterial cells were delivered in a fermented milk formula, a significant improvement of survival in the TIM was observed compared to non-fermented milk. With the RIVET (Recombinase In Vivo Expression Technology) method applied to the LMD9 strain, a promoter located upstream of hisS, responsible for the histidyl-transfer RNA synthesis, was found to be specifically activated in the artificial stomach. The data generated on S. thermophilus survival and its adaptation capacities to the digestive tract are essential to establish a list of biomarkers useful for the selection of probiotic strains.
Journal of Agricultural and Food Chemistry, 60 (2), pp 554-565.
Miclo, L., Roux, E., Genay, M., Brusseaux, E., Poirson, C., Jameh, N., Perrin, C., Dary, A.
Milk proteins contain numerous potential bioactive peptides, which may be released by digestive proteases or by the proteolytic system of lactic acid bacteria during food processing. The capacity of Streptococcus thermophilus to generate peptides, especially bioactive peptides, from bovine caseins was investigated. Strains expressing various levels of the Cell Envelope Proteinase, PrtS, were incubated either with αs1-, αs2- or β-casein. Analysis of the supernatants by LC-ESI-MS/MS showed that the β-casein was preferentially hydrolyzed first, followed by αs2-casein and then αs1-casein. Numbers and types of peptides released were strain-dependent. Hydrolysis appeared to be linked with the accessibility of different casein regions by protease. Analysis of bonds hydrolyzed in the region 1-23 of αs1-casein suggests that PrtS is at least in part responsible for the peptide production. Finally, among the generated peptides, 13 peptides from β-casein, 5 from αs2-casein and 2 from αs1-casein have been reported as bioactive, 15 of them being angiotensin-converting enzyme inhibitors.
Milk-clotting activity of enzyme extracts from sunflower and albizia seeds and specific hydrolysis of bovine kappa-casein
International Dairy Journal, 17 (7), pp. 816-825.
Egito, A.S., Girardet, J.-M., Laguna, L.E., Poirson, C., Molle, D., Miclo, L., Humbert, G., Gaillard, J.-L.
Milk-clotting activity found in ammonium sulfate-precipitated protein extracts from Albizia lebbeck and Helianthus annuus seeds was studied. Specific clotting activity of albizia seed extract was 15 times higher than that of sunflower seed extract. Zymogram analysis revealed several proteolytic bands in albizia seed extract and one diffuse proteolytic band for sunflower seed extract. Whole bovine casein was incubated with the plant seed extracts or chymosin and some breakdown products were characterized by reversed-phase high-performance liquid chromatography and electrophoresis. Similar to chymosin, the two seed extracts exhibited proteolytic activity toward κ-casein, αs-casein and β-casein, with the highest activity observed for the albizia seed extract. Mass spectrometry analysis showed that the sunflower extract hydrolyzed κ-casein at the Phe105–Met106 bond, as does chymosin. The albizia extract also displayed activity on κ-casein, but the Lys116–Thr117 bond was its preferred target.
17e Colloque du Club des Bactéries Lactiques (CBL), 27-29 octobre, Nancy, France
Roux, E., Miclo, L., Brusseaux, E., Poirson, C., Perrin, C., Dary, A.
Rapport de contrat avec le Centre Interprofessionnel de l’Économie Laitière (CNIEL), 55 p.
Miclo, L., Brusseaux, E., Poirson, C., Perrin, C., Dary, A.
