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Partager le résultat de cette recherche Interroger des sources externesYaourts probiotiques algériens et ferments commerciaux utilisés dans leur fabrication / Amina Bouchefra
Titre : Yaourts probiotiques algériens et ferments commerciaux utilisés dans leur fabrication : contrôle de qualité et de l’étiquetage. Type de document : texte imprimé Auteurs : Amina Bouchefra, Auteur ; Rihab Boushaba, Directeur de thèse Editeur : Constantine : Université Mentouri Constantine Année de publication : 2012 Importance : 118 f. Format : 31 cm. Note générale : 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais
Nutrition, Alimentation et Technologies Agro-AlimentairesTags : Biotechnologie Alimentaire: Sciences Alimentaires Diluant ferment lactique in vitro probiotique produits laitiers fermentés viabilité Diluent lactic ferment probiotic fermented milk products viability المذيبات الخمائر اللبنية البروبيوتيك مختبر منتجات الحليب المخمرة Index. décimale : 640 Industrie Alimentaire Résumé :
Fermented milk products are generally regarded by consumers as healthy and as such, they represent an important part of the diet. The incorporation of probiotic bacteria as dietary supplements in various fermented milk-derived products has enhanced their acclaimed healthy properties and lead to increased consumption of these products. However, the efficiency of probiotics depends on their viability which needs to be maintained during the manufacturing, storage and conservation processes. In addition, the probiotic strains must survive the environment of the gastrointestinal tract. The viability of probiotics is therefore a key factor in the ability of commrcialized strains to provide the desired effects. In addition, recent controversies have sparked an international debate with regards to approaches to regulate this new category of food products. This study comprises two main parts: (1) Microbiological quality control and analysis of health claims in the labeling of yogurts marketed in Algeria as "probiotic" and (2) Quality control, evaluation of some probiotic properties and the viability of three samples of commercial cultures collected from an Algerian dairy company. Two of these samples are used as starter cultures and the other as an additive to manufacture probiotic yogurts. We tested the probiotic lactic acid bacteria delivered in two yogurts manufactured in Algeria and commercialized as "probiotics". The effect of the solution used to prepare decimal dilutions for the enumeration of these bacteria on the result of the count was examined. We also examined the labeling of five yogurts which are commercialized as "probiotics". In addition, we assessed various characteristics of probiotics in vitro, namely resistance to acid, bile tolerance and antimicrobial activity of three samples of commercial DVS cultures used in the Algerian dairy industry to manufacture probiotic yogurts: ST-M6 (Streptococcus thermophilus), LB-12 (Lactobacillus delbrueckii subsp. bulgaricus) and LA-5 (Lactobacillus acidophilus). Finally, we assessed the influence of technological conditions (cold storage, acidity, addition of artificial flavors and thickening agents) on the viability of these lactic bacteria samples.Note de contenu :
Annexes.Diplôme : Magistère En ligne : ../theses/agronomie/BOU6116.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=5998 Yaourts probiotiques algériens et ferments commerciaux utilisés dans leur fabrication : contrôle de qualité et de l’étiquetage. [texte imprimé] / Amina Bouchefra, Auteur ; Rihab Boushaba, Directeur de thèse . - Constantine : Université Mentouri Constantine, 2012 . - 118 f. ; 31 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
Nutrition, Alimentation et Technologies Agro-AlimentairesTags : Biotechnologie Alimentaire: Sciences Alimentaires Diluant ferment lactique in vitro probiotique produits laitiers fermentés viabilité Diluent lactic ferment probiotic fermented milk products viability المذيبات الخمائر اللبنية البروبيوتيك مختبر منتجات الحليب المخمرة Index. décimale : 640 Industrie Alimentaire Résumé :
Fermented milk products are generally regarded by consumers as healthy and as such, they represent an important part of the diet. The incorporation of probiotic bacteria as dietary supplements in various fermented milk-derived products has enhanced their acclaimed healthy properties and lead to increased consumption of these products. However, the efficiency of probiotics depends on their viability which needs to be maintained during the manufacturing, storage and conservation processes. In addition, the probiotic strains must survive the environment of the gastrointestinal tract. The viability of probiotics is therefore a key factor in the ability of commrcialized strains to provide the desired effects. In addition, recent controversies have sparked an international debate with regards to approaches to regulate this new category of food products. This study comprises two main parts: (1) Microbiological quality control and analysis of health claims in the labeling of yogurts marketed in Algeria as "probiotic" and (2) Quality control, evaluation of some probiotic properties and the viability of three samples of commercial cultures collected from an Algerian dairy company. Two of these samples are used as starter cultures and the other as an additive to manufacture probiotic yogurts. We tested the probiotic lactic acid bacteria delivered in two yogurts manufactured in Algeria and commercialized as "probiotics". The effect of the solution used to prepare decimal dilutions for the enumeration of these bacteria on the result of the count was examined. We also examined the labeling of five yogurts which are commercialized as "probiotics". In addition, we assessed various characteristics of probiotics in vitro, namely resistance to acid, bile tolerance and antimicrobial activity of three samples of commercial DVS cultures used in the Algerian dairy industry to manufacture probiotic yogurts: ST-M6 (Streptococcus thermophilus), LB-12 (Lactobacillus delbrueckii subsp. bulgaricus) and LA-5 (Lactobacillus acidophilus). Finally, we assessed the influence of technological conditions (cold storage, acidity, addition of artificial flavors and thickening agents) on the viability of these lactic bacteria samples.Note de contenu :
Annexes.Diplôme : Magistère En ligne : ../theses/agronomie/BOU6116.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=5998 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BOU/6116 BOU/6116 Thèse Bibliothèque principale Thèses Disponible
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
