Influence du levain et d’une culture secondaire de lactobacilles sur l’affinage des fromages miniatures type pâte pressée

Ten strains of Lactobacillus were tested as adjunct cultures in combination with two different Lactocococcus lactis starters in miniature washed-curd cheeses manufactured under controlled bacteriological conditions. Growth of lactobacilli seemed to depend on the strain used, but was not influenced by the starter strain (either L. lactis subsp. lactis lL416 or L. lactis subsp. cremoris AM2). Lactococcal counts in miniature cheeses with AM2 starter and added lactobacilli were higher than in control cheeses without lactobacilli. Consistently good survival (~100% after four weeks) was observed for IL416, regardless of the presence of adjunct culture). In contrast, AM2 starter cell viability decreased slowly over the same time period. Gross composition and protein analyses were performed on the miniature cheeses. Our results indicate that production of soluble nitrogenous compounds was influenced by the lactobacilli adjunct, and depended on the starter strain. We conclude that the use of different combinations of starter and adjunct cultures can result in marked differences in bacterial populations and product properties. Such studies may be used to choose the combination of strains necessary to obtain a product with particular properties.Dix souches de lactobacilles de la collection CNRZ ont été testées en tant que culture secondaire, en combinaison avec deux souches différentes de levain Lactococcus lactis, dans des fromages miniatures type pâte pressée fabriqués en conditions bactériologiques contrôlées. La croissance des lactobacilles semble dépendre de la souche utilisée, mais elle n’est pas influencée par la souche de levain (L. lactis subsp. lactis IL416 ou L. lactis subsp. cremoris AM2). La numération des lactocoques dans les fromages miniatures fabriqués avec la souche AM2 et addition de lactobacilles est plus élevée que dans les fromages témoins sans ajout de lactobacilles. Comme attendue, une bonne survie a été observée pour IL416 (~100 % après quatre semaines), et ce indépendamment de la présence d’une culture secondaire. Au contraire, la viabilité de AM2 a décru au cours de la même période. La composition globale et des analyses biochimiques ont été réalisées sur les fromages miniatures. Nos résultats indiquent que l’addition de lactobacilles influence la production de composés azotés solubles en liaison avec la souche de levain. Nous concluons qu’en utilisant différentes combinaisons de lactocoques et de cultures secondaires, on peut obtenir des différences marquées dans les populations bactériennes et les propriétés des produits. De telles études pourraient être utilisées pour choisir les combinaisons de souches nécessaires pour obtenir un produit avec des propriétés spécifiques.Fil: Hynes, Erica Rut. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; ArgentinaFil: Ogier, Jean Claude. Unité de Recherches Laitières et Génétique Appliquée; FranciaFil: Son, Olivier. Unité de Recherches Laitières et Génétique Appliquée; FranciaFil: Delacroix Buchet, Agnès. Unité de Recherches Laitières et Génétique Appliquée; Franci

Contribution du levain et d’une culture secondaire de lactobacilles à la protéolyse, au profil des composés volatils et aux caractéristiques sensorielles de fromages à pâte pressée

Washed-curd cheeses manufactured with either Lactococcus lactis subsp. lactis IL416 or Lactococcus lactis subsp. cremoris AM2 were used to test the role of six Lactobacillus strains from the CNRZ collection as adjunct cultures. Proteolysis and volatile profile determinations were performed on all cheeses after 28 days of ripening; a trained panel assessed sensory characteristics. We observed that overall, the lactococcal starter strains had a major influence on cheese taste and texture. Control cheeses manufactured with the strain IL416 were mild. Lactobacilli adjunct addition to cheeses manufactured with the strain IL416 had a strong effect on their flavour attributes. In contrast, control cheeses manufactured with the strain AM2 had greater flavour intensities and were saltier and more acidic. These cheeses were more affected in their texture profile and overall flavour intensity, and to a lesser extent in their flavour profile by lactobacilli addition. In summary, while the major cheese characteristics are determined by the starter strain used, addition of lactobacilli adjuncts L. plantarum 1572, L. plantarum 1310 and L. casei 1227 can affect flavour and texture of washed-curd cheese products.Des fromages à pâte pressée ont été fabriqués avec soit Lactococcus lactis subsp. lactis IL416, soit Lactococcus lactis subsp. cremoris AM2 pour tester le rôle de six souches de lactobacilles de la collection CNRZ en tant que culture secondaire. La protéolyse et le profil des composés volatils ont été déterminés sur tous les fromages après 28 jours d'affinage et un jury entraîné a établi leur profil sensoriel. Nous observons avant tout une influence majeure de la souche de levain lactocoque sur le goût et la texture des fromages. Les fromages témoins fabriqués avec la souche IL416 sont neutres et l'ajout d'une culture secondaire de lactobacilles a un fort impact sur les attributs de flaveur de ces fromages. Au contraire, les fromages témoins fabriqués avec la souche AM2 possèdent une plus forte intensité de flaveur, ils sont plus salés et plus acides. La texture et l'intensité globale de flaveur et, dans une moindre mesure, le profil de flaveur de ces fromages sont aussi davantage affectés par l'apport d'une culture secondaire de lactobacilles. En résumé, si les caractéristiques principales des fromages sont déterminées par la souche de levain, l'ajout d'une culture secondaire des souches de lactobacilles L. plantarum 1572, L. plantarum 1310 ou L. casei 1227 peut modifier la flaveur et la texture de fromages à pâte pressée.Fil: Hynes, Erica Rut. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; ArgentinaFil: Bach, Cyrille. Unité de Recherches Laitières et Génétique Appliquée; FranciaFil: Lamberet, Gilles. Unité de Recherches Laitières et Génétique Appliquée; FranciaFil: Ogier, Jean Claude. Unité de Recherches Laitières et Génétique Appliquée; FranciaFil: Son, Olivier. Unité de Recherches Laitières et Génétique Appliquée; FranciaFil: Delacroix Buchet, Agnès. Unité de Recherches Laitières et Génétique Appliquée; Franci

Sequence-based GWAS, network and pathway analyses reveal genes co-associated with milk cheese-making properties and milk composition in Montbéliarde cows

Background Milk quality in dairy cattle is routinely assessed via analysis of mid-infrared (MIR) spectra; this approach can also be used to predict the milk’s cheese-making properties (CMP) and composition. When this method of high-throughput phenotyping is combined with efficient imputations of whole-genome sequence data from cows’ genotyping data, it provides a unique and powerful framework with which to carry out genomic analyses. The goal of this study was to use this approach to identify genes and gene networks associated with milk CMP and composition in the Montbéliarde breed. Results Milk cheese yields, coagulation traits, milk pH and contents of proteins, fatty acids, minerals, citrate, and lactose were predicted from MIR spectra. Thirty-six phenotypes from primiparous Montbéliarde cows (1,442,371 test-day records from 189,817 cows) were adjusted for non-genetic effects and averaged per cow. 50 K genotypes, which were available for a subset of 19,586 cows, were imputed at the sequence level using Run6 of the 1000 Bull Genomes Project (comprising 2333 animals). The individual effects of 8.5 million variants were evaluated in a genome-wide association study (GWAS) which led to the detection of 59 QTL regions, most of which had highly significant effects on CMP and milk composition. The results of the GWAS were further subjected to an association weight matrix and the partial correlation and information theory approach and we identified a set of 736 co-associated genes. Among these, the well-known caseins, PAEP and DGAT1, together with dozens of other genes such as SLC37A1, ALPL, MGST1, SEL1L3, GPT, BRI3BP, SCD, GPAT4, FASN, and ANKH, explained from 12 to 30% of the phenotypic variance of CMP traits. We were further able to identify metabolic pathways (e.g., phosphate and phospholipid metabolism and inorganic anion transport) and key regulator genes, such as PPARA, ASXL3, and bta-mir-200c that are functionally linked to milk composition. Conclusions By using an approach that integrated GWAS with network and pathway analyses at the whole-genome sequence level, we propose candidate variants that explain a substantial proportion of the phenotypic variance of CMP traits and could thus be included in genomic evaluation models to improve milk CMP in Montbéliarde cows.info:eu-repo/semantics/publishedVersio

Sequence-based GWAS, network and pathway analyses reveal genes co-associated with milk cheese-making properties and milk composition in Montbéliarde cows

International audienceAbstractBackgroundMilk quality in dairy cattle is routinely assessed via analysis of mid-infrared (MIR) spectra; this approach can also be used to predict the milk’s cheese-making properties (CMP) and composition. When this method of high-throughput phenotyping is combined with efficient imputations of whole-genome sequence data from cows’ genotyping data, it provides a unique and powerful framework with which to carry out genomic analyses. The goal of this study was to use this approach to identify genes and gene networks associated with milk CMP and composition in the Montbéliarde breed.ResultsMilk cheese yields, coagulation traits, milk pH and contents of proteins, fatty acids, minerals, citrate, and lactose were predicted from MIR spectra. Thirty-six phenotypes from primiparous Montbéliarde cows (1,442,371 test-day records from 189,817 cows) were adjusted for non-genetic effects and averaged per cow. 50 K genotypes, which were available for a subset of 19,586 cows, were imputed at the sequence level using Run6 of the 1000 Bull Genomes Project (comprising 2333 animals). The individual effects of 8.5 million variants were evaluated in a genome-wide association study (GWAS) which led to the detection of 59 QTL regions, most of which had highly significant effects on CMP and milk composition. The results of the GWAS were further subjected to an association weight matrix and the partial correlation and information theory approach and we identified a set of 736 co-associated genes. Among these, the well-known caseins, PAEP and DGAT1, together with dozens of other genes such as SLC37A1, ALPL, MGST1, SEL1L3, GPT, BRI3BP, SCD, GPAT4, FASN, and ANKH, explained from 12 to 30% of the phenotypic variance of CMP traits. We were further able to identify metabolic pathways (e.g., phosphate and phospholipid metabolism and inorganic anion transport) and key regulator genes, such as PPARA, ASXL3, and bta-mir-200c that are functionally linked to milk composition.ConclusionsBy using an approach that integrated GWAS with network and pathway analyses at the whole-genome sequence level, we propose candidate variants that explain a substantial proportion of the phenotypic variance of CMP traits and could thus be included in genomic evaluation models to improve milk CMP in Montbéliarde cows

Proteolyse et texture des fromages a pate cuite pressee. II. Influence de la chymosine et des conditions de fabrication

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Proteolyse et texture des fromages a pate cuite pressee . I . Influence de l'activite de l'eau

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Polymorphisme de la caseine kappa de trois races bovines francaises et aptitude a la coagulation

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Biodiversity of Bacterial Ecosystems in Traditional Egyptian Domiati Cheese

Bacterial biodiversity occurring in traditional Egyptian soft Domiati cheese was studied by PCR-temporal temperature gel electrophoresis (TTGE) and PCR-denaturing gradient gel electrophoresis (DGGE). Bands were identified using a reference species database (J.-C. Ogier et al., Appl. Environ. Microbiol. 70:5628-5643, 2004); de novo bands having nonidentified migration patterns were identified by DNA sequencing. Results reveal a novel bacterial profile and extensive bacterial biodiversity in Domiati cheeses, as reflected by the numerous bands present in TTGE and DGGE patterns. The dominant lactic acid bacteria (LAB) identified were as follows: Leuconostoc mesenteroides, Lactococcus garvieae, Aerococcus viridans, Lactobacillus versmoldensis, Pediococcus inopinatus, and Lactococcus lactis. Frequent non-LAB species included numerous coagulase-negative staphylococci, Vibrio spp., Kocuria rhizophila, Kocuria kristinae, Kocuria halotolerans, Arthrobacter spp./Brachybacterium tyrofermentans. This is the first time that the majority of these species has been identified in Domiati cheese. Nearly all the dominant and frequent bacterial species are salt tolerant, and several correspond to known marine bacteria. As Domiati cheese contains 5.4 to 9.5% NaCl, we suggest that these bacteria are likely to have an important role in the ripening process. This first systematic study of the microbial composition of Domiati cheeses reveals great biodiversity and evokes a role for marine bacteria in determining cheese type

Caracterisation de l'Emmental Grand-Cru francais . I . Composition physico-chimique

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Une approche globale de la caracterisation des fromages: l'exemple du fromage de Beaufort

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