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Auteur Nadia Benhedane née Bachtarzi |
Documents disponibles écrits par cet auteur (2)
Affiner la recherche Interroger des sources externesCaractérisation des bactéries lactiques autochtones productrices d’exopolysaccharides et étude de leurs effets intrinsèques sur une matrice laitière. / Nadia Benhedane née Bachtarzi
Titre : Caractérisation des bactéries lactiques autochtones productrices d’exopolysaccharides et étude de leurs effets intrinsèques sur une matrice laitière. Type de document : texte imprimé Auteurs : Nadia Benhedane née Bachtarzi, Auteur ; Karima Kharroub, Directeur de thèse ; Patricia Ruas-Madiedo, Directeur de thèse Mention d'édition : 02/11/2020 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2020 Importance : 226 f. Format : 30 cm. Note générale : 1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
Nutrition, Alimentation et Technologies Agro-AlimentairesTags : Biotechnologie: Sciences Alimentaires fermented dairy products lactic acid bacteria exopolysaccharides structure viscosity produits laitiers fermentés bactéries lactiques viscosité منتجات الألبان المخمرة بكتيريا حمض اللاكتيك السكريات الخارجية البنية اللزوجة Index. décimale : 640 Industrie Alimentaire Résumé :
The naturally fermented dairy products are an interesting source of new strains of lactic acid bacteria (LAB) with proven technological potential. Some of them are capable of synthesizing exopolysaccharides (EPS) during fermentation, which improve the rheological properties of dairy matrices. This thesis work focuses on the selection of LAB producing EPS from local fermented dairy products. A total of 30 samples were collected in Eastern Algeria, from which 584 presumptive isolates of LAB were tested for the production of EPS. Only 18 isolates presented a productive phenotype, their polyphasic characterization confirmed that they belong to two species: Leuconostoc mesenteroides and Lactobacillus plantarum. A preselection based on the stability of EPS production character made it possible to retain 6 strains in addition to a control strain, all affiliated to the Lactobacillus plantarum species. Then macroscopic characterization of their lactic gels allowed to select two strains LBIO1 and LBIO28 producing viscosifying EPS in a dairy matrix. The study of their production revealed that the polymers produced are primary metabolites, with a high molecular weight. In parallel, a characterization of the macro and microstructure under confocal laser scanning microscopy of the two gels SMCLBIO1 and SMCLBIO28, compared to the control gel SMCLBIO14, concluded that the EPS of the two ropy strains contribute significantly to the improvement of the physical attributes of lactic gels. Furthermore, micrographs made by cryo-electron microscopy showed the existence of a dense web-like EPS attached to the cells for both ropy strains, which is not observed for LBIO14. Finally, a complete sequencing of the three genomes followed by an in silico genomic analysis confirmed the safety of the strains and the existence of genes coding for bacteriocins and vitamins. The study of the biosynthetic machinery of EPS in comparison with the reference strain Lactobacillus plantarum WCF1 revealed the presence of 2 complete eps clusters cps3 and cps4 in the three genomes with 100% similarity between them, all chromosomal. However, the two strains LBIO1 and LBIO28 have in addition genes belonging to cps2, which would therefore be involved in the synthesis of the ropy polymer with high molecular weight. The two ropy strains LBIO1 and LBIO28 can therefore be exploited in dairy fermentation, based on the techno-functional properties of their polymers, which contribute to the improvement of the rheological characteristics of the matrices generated.
Diplôme : Doctorat en sciences En ligne : ../theses/agronomie/BAC7671.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11505 Caractérisation des bactéries lactiques autochtones productrices d’exopolysaccharides et étude de leurs effets intrinsèques sur une matrice laitière. [texte imprimé] / Nadia Benhedane née Bachtarzi, Auteur ; Karima Kharroub, Directeur de thèse ; Patricia Ruas-Madiedo, Directeur de thèse . - 02/11/2020 . - جامعة الإخوة منتوري قسنطينة, 2020 . - 226 f. ; 30 cm.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
Nutrition, Alimentation et Technologies Agro-AlimentairesTags : Biotechnologie: Sciences Alimentaires fermented dairy products lactic acid bacteria exopolysaccharides structure viscosity produits laitiers fermentés bactéries lactiques viscosité منتجات الألبان المخمرة بكتيريا حمض اللاكتيك السكريات الخارجية البنية اللزوجة Index. décimale : 640 Industrie Alimentaire Résumé :
The naturally fermented dairy products are an interesting source of new strains of lactic acid bacteria (LAB) with proven technological potential. Some of them are capable of synthesizing exopolysaccharides (EPS) during fermentation, which improve the rheological properties of dairy matrices. This thesis work focuses on the selection of LAB producing EPS from local fermented dairy products. A total of 30 samples were collected in Eastern Algeria, from which 584 presumptive isolates of LAB were tested for the production of EPS. Only 18 isolates presented a productive phenotype, their polyphasic characterization confirmed that they belong to two species: Leuconostoc mesenteroides and Lactobacillus plantarum. A preselection based on the stability of EPS production character made it possible to retain 6 strains in addition to a control strain, all affiliated to the Lactobacillus plantarum species. Then macroscopic characterization of their lactic gels allowed to select two strains LBIO1 and LBIO28 producing viscosifying EPS in a dairy matrix. The study of their production revealed that the polymers produced are primary metabolites, with a high molecular weight. In parallel, a characterization of the macro and microstructure under confocal laser scanning microscopy of the two gels SMCLBIO1 and SMCLBIO28, compared to the control gel SMCLBIO14, concluded that the EPS of the two ropy strains contribute significantly to the improvement of the physical attributes of lactic gels. Furthermore, micrographs made by cryo-electron microscopy showed the existence of a dense web-like EPS attached to the cells for both ropy strains, which is not observed for LBIO14. Finally, a complete sequencing of the three genomes followed by an in silico genomic analysis confirmed the safety of the strains and the existence of genes coding for bacteriocins and vitamins. The study of the biosynthetic machinery of EPS in comparison with the reference strain Lactobacillus plantarum WCF1 revealed the presence of 2 complete eps clusters cps3 and cps4 in the three genomes with 100% similarity between them, all chromosomal. However, the two strains LBIO1 and LBIO28 have in addition genes belonging to cps2, which would therefore be involved in the synthesis of the ropy polymer with high molecular weight. The two ropy strains LBIO1 and LBIO28 can therefore be exploited in dairy fermentation, based on the techno-functional properties of their polymers, which contribute to the improvement of the rheological characteristics of the matrices generated.
Diplôme : Doctorat en sciences En ligne : ../theses/agronomie/BAC7671.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11505 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BAC/7671 BAC/7671 Thèse Bibliothèque principale Thèses Disponible
Titre : Qualite microbiologique du lait cru destine a la fabrication d’un type de camembert dans une unite de l’est Algerien. Type de document : texte imprimé Auteurs : Nadia Benhedane née Bachtarzi, Auteur ; Leila Amourache, Directeur de thèse Editeur : Constantine : Université Mentouri Constantine Année de publication : 2012 Importance : 102 f. Format : 31 cm. Note générale : 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais
Nutrition, Alimentation et Technologies Agro-AlimentairesTags : Sciences Alimentaires: Biotechnologie Alimentaire Lait qualité microbiologie hygiène Milk Quality Microbiology Hygiene الحليب الجودة علم الأحياء المجهرية النظافة Index. décimale : 640 Industrie Alimentaire Résumé : Samples of raw milk (30), for the manufacture of Camembert type cheese at a dairy in eastern Algeria, were analyzed during the period of high lactation (February-April 2011). The results of physico-chemical characteristics (acidity and density) are close to the standards, only the fat content is low, with an average of 30.9 g / l, it depends mainly on the dietary factor. Microbiological analysis is focused on 9 microbial groups: among the groups hygiene indicators (total bacteria, psychrotrophic, thermoduric, coliform and Escherichia coli) and
some groups potentially pathogens (Staphylococcus aureus, Salmonella). Contamination levels were interpreted on the basis of microbiological criteria set by the ministerial decree of 24 January 1998. Enumeration of total aerobic mesophilic flora, psychrotrophic and thermoduric of serves to underscore the severe contamination of the samples analyzed with respective averages of 28,8.106 CFU / ml, 12,3.105 CFU / ml and 44,2.104 CFU/ml. Milk samples are contaminated with total coliforms, fecal coliforms and fecal streptococci with average respective 50,3.105 CFU / ml, 36,7.104 CFU / ml and 55,4.105 CFU/ml. The germ E. coli is present in 64% of milk analyzed. The presence of pathogens is mainly attributed to staphylococci with an average of 37,5.102 CFU /ml, 80% of isolates were coagulase positive. The study of their susceptibility patterns to antibiotics showed a frequency of resistance (100%) vis-à-vis penicillin G, very little resistance vis-à-vis the oxaciline (8%) of tetracycline (17%) and trimethoprim + sulfamethoxazole association (17%). No resistance was observed for cefoxitin, erythromycin, enrofloxacin, and vancomycin. Moreover, we note the absence of Salmonella in all samples. In view of the Algerian standards (JORA, 1998), the hygienic quality of all milk samples analyzed, is bad. Milks are heavily polluted, revealing questionable hygiene practices, that even the best cooling conditions of milk, can not, under any circumstances, hide. These results can only strengthen the conviction of the
urgent need for technical support in this area, coupled with the revision of payment of milk: the inclusion criteria daily as basic as the milk fat and protein and contamination by microorganisms. There will surely sustainability in Algeria of a dairy industry that is capable of distinguishing the various versions of a product as variable and perishable as milk.Note de contenu : Annexes. Diplôme : Magistère En ligne : ../theses/agronomie/BEN6202.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=6177 Qualite microbiologique du lait cru destine a la fabrication d’un type de camembert dans une unite de l’est Algerien. [texte imprimé] / Nadia Benhedane née Bachtarzi, Auteur ; Leila Amourache, Directeur de thèse . - Constantine : Université Mentouri Constantine, 2012 . - 102 f. ; 31 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
Nutrition, Alimentation et Technologies Agro-AlimentairesTags : Sciences Alimentaires: Biotechnologie Alimentaire Lait qualité microbiologie hygiène Milk Quality Microbiology Hygiene الحليب الجودة علم الأحياء المجهرية النظافة Index. décimale : 640 Industrie Alimentaire Résumé : Samples of raw milk (30), for the manufacture of Camembert type cheese at a dairy in eastern Algeria, were analyzed during the period of high lactation (February-April 2011). The results of physico-chemical characteristics (acidity and density) are close to the standards, only the fat content is low, with an average of 30.9 g / l, it depends mainly on the dietary factor. Microbiological analysis is focused on 9 microbial groups: among the groups hygiene indicators (total bacteria, psychrotrophic, thermoduric, coliform and Escherichia coli) and
some groups potentially pathogens (Staphylococcus aureus, Salmonella). Contamination levels were interpreted on the basis of microbiological criteria set by the ministerial decree of 24 January 1998. Enumeration of total aerobic mesophilic flora, psychrotrophic and thermoduric of serves to underscore the severe contamination of the samples analyzed with respective averages of 28,8.106 CFU / ml, 12,3.105 CFU / ml and 44,2.104 CFU/ml. Milk samples are contaminated with total coliforms, fecal coliforms and fecal streptococci with average respective 50,3.105 CFU / ml, 36,7.104 CFU / ml and 55,4.105 CFU/ml. The germ E. coli is present in 64% of milk analyzed. The presence of pathogens is mainly attributed to staphylococci with an average of 37,5.102 CFU /ml, 80% of isolates were coagulase positive. The study of their susceptibility patterns to antibiotics showed a frequency of resistance (100%) vis-à-vis penicillin G, very little resistance vis-à-vis the oxaciline (8%) of tetracycline (17%) and trimethoprim + sulfamethoxazole association (17%). No resistance was observed for cefoxitin, erythromycin, enrofloxacin, and vancomycin. Moreover, we note the absence of Salmonella in all samples. In view of the Algerian standards (JORA, 1998), the hygienic quality of all milk samples analyzed, is bad. Milks are heavily polluted, revealing questionable hygiene practices, that even the best cooling conditions of milk, can not, under any circumstances, hide. These results can only strengthen the conviction of the
urgent need for technical support in this area, coupled with the revision of payment of milk: the inclusion criteria daily as basic as the milk fat and protein and contamination by microorganisms. There will surely sustainability in Algeria of a dairy industry that is capable of distinguishing the various versions of a product as variable and perishable as milk.Note de contenu : Annexes. Diplôme : Magistère En ligne : ../theses/agronomie/BEN6202.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=6177 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BEN//6202 BEN//6202 Thèse Bibliothèque principale Thèses Disponible
