La fermentation de matières premières végétales

Les produits fermentés sont consommés dans le monde entier depuis des siècles.Les végétaux fermentés font l’objet d’un regain d’intérêt, suivant les tendances du végétarisme, de la recherche de naturalité et du développement durable.Le CTCPA et le pôle de compétitivité VEGEPOLYS vous proposent ce séminaire de formation, au cours duquel leurs intervenants feront le point sur les tendances de ce marché, sur l’état de l’art et les limites des connaissances techniques et scientifiques sur le sujet

First Insight into the Technological Features of Lactic Acid Bacteria Isolated from Algerian Fermented Wheat Lemzeiet

Fermented cereals are part of the main traditional diets of many people in Africa, usually obtained from artisanal production.The intensification of their manufacturing, responding to the consumers demand, requires a better control to ensure their sanitary, nutritional, and taste qualities, hence, the need of selecting accurate and safe starter cultures. In the present study, 48 lactic acid bacteria (LAB) strains, previously isolated from Algerian fermented wheat lemzeiet, were analyzed for different technological properties. 14 LAB strains, belonging to Pediococcus pentosaceus, Enterococcus faecium, Lactobacillus curvatus, Lactobacillus brevis, and Leuconostoc mesenteroides species, decreased rapidly the pH of the flour extract brothclose to 4 or below. 91% of strains showed extracellular protease activity, but only 12% were amylolytics. 18 LAB strains inhibited or postponed the growth of three fungal targets Rhodotorula mucilaginosa UBOCC-A-216004, Penicillium verrucosum UBOCC-A-109221, and Aspergillus flavus UBOCC-A-106028. The strains belonging to Lactobacillus spp., Leuconostoc fallax, L. mesenteroides, and Weissella paramesenteroides were the most antifungal ones. Multiplex PCR for biogenic amines’ production did not reveal any of the genes involved in the production of putrescine, histamine, and tyramine for 17 of the 48 strains. The obtained results provided several candidates for use as starter culture in the future production of lemzeiet

Selective enumeration of propionibacteria in Emmental-type cheese using PetrifilmTM Aerobic count plates added to lithium glycerol broth

Propionibacteria derived from dairy products are relevant starter cultures for the production of Swiss and Emmental-type cheeses, and the monitoring of which is mandatory for proper quality control. This study aimed to evaluate an alternative procedure to enumerate propionibacteria, in order to develop a reliable and practical methodology to be employed by dairy industries. 2,3,5-triphenyltetrazolium chloride (TTC) inhibitory activity was tested against five reference strains (CIRM 09, 38, 39, 40 and 116); TTC at 0·0025% (w/v) was not inhibitory, with the exception of one strain (CIRM 116). Subsequently, the four TTC-resistant strains, three commercial starter cultures (PS-1, PB-I, and CHOO) and twelve Emmental-type cheese samples were subjected to propionibacteria enumeration using Lithium Glycerol (LG) agar, and Petrifilm™ Aerobic Count (AC) plates added to LG broth (anaerobic incubation at 30 °C for 7 d). Petrifilm™ AC added to LG broth presented high counts than LG agar (P<0·05) for only two reference strains (CIRM 39, and 40) and for all commercial starter cultures. Cheese sample counts obtained by both procedures did not show significant differences (P<0·05). Significant correlation indexes were observed between the counts recorded by both methods (P<0·05). These results demonstrate the reliability of Petrifilm™ AC plates added to LG broth in enumerating select Propionibacterium spp., despite some limitations observed for specific commercial starter cultures

New insights about phenotypic heterogeneity within Propionibacterium freudenreichii argue against its division into subspecies

Propionibacterium freudenreichii is widely used in Swiss-type cheese manufacture, where it contributes to flavour and eye development. It is currently divided into two subspecies, according to the phenotype for lactose fermentation and nitrate reduction (lac+/nit- and lac-/nit+ for P. freudenreichii subsp. shermanii and subsp. freudenreichii, respectively). However, the existence of unclassifiable strains (lac+/nit+ and lac-/nit-) has also been reported. The aim of this study was to revisit the relevance of the subdivision of P. freudenreichii into subspecies, by confirming the existence of unclassifiable strains. Relevant conditions to test the ability of P. freudenreichii for lactose fermentation and nitrate reduction were first determined, by using 10 sequenced strains, in which the presence or absence of the lactose and nitrate genomic islands were known. We also determined whether the subdivision based on lac/nit phenotype was related to other phenotypic properties of interest in cheese manufacture, in this case, the production of aroma compounds, analysed by gas chromatography-mass spectrometry, for a total of 28 strains. The results showed that a too short incubation time can lead to false negative for lactose fermentation and nitrate reduction. They confirmed the existence of four lac/nit phenotypes instead of the two expected, thus leading to 13 unclassifiable strains out of the 28 characterized (7 lac+/nit+ and 6 lac-/nit-). The production of the 15 aroma compounds detected in all cultures varied more within a lac/nit phenotype (up to 20 times) than between them. Taken together, these results demonstrate that the division of P. freudenreichii into two subspecies does not appear to be relevant.Fil: de Freitas, Rosangela. Universidade Federal de Viçosa. Departamento de Tecnologia de Alimentos; Brasil. Institut National de la Recherche Agronomique; Francia. Science et Technologie du Lait et de l; FranciaFil: Madec, Marie Noelle. Institut National de la Recherche Agronomique; Francia. Science et Technologie du Lait et de l; FranciaFil: Chuat, Victoria. Institut National de la Recherche Agronomique; Francia. Science et Technologie du Lait et de l; FranciaFil: Maillard, Marie Bernadette. Institut National de la Recherche Agronomique; Francia. Science et Technologie du Lait et de l; FranciaFil: Abeijon Mukdsi, Maria Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentina. Institut National de la Recherche Agronomique; Francia. Science et Technologie du Lait et de l; FranciaFil: Falentin, Hélène. Institut National de la Recherche Agronomique; Francia. Science et Technologie du Lait et de l; FranciaFil: Carvalho, Antonio Fernandes de. Universidade Federal de Viçosa. Departamento de Tecnologia de Alimentos; BrasilFil: Valence, Florence. Institut National de la Recherche Agronomique; Francia. Science et Technologie du Lait et de l; FranciaFil: Thierry, Anne. Institut National de la Recherche Agronomique; Francia. Science et Technologie du Lait et de l; Franci

An MDA approach for developing Secure OLAP applications: metamodels and transformations

Decision makers query enterprise information stored in Data Warehouses (DW) by using tools (such as On-Line Analytical Processing (OLAP) tools) which employ specific views or cubes from the corporate DW or Data Marts, based on multidimensional modelling. Since the information managed is critical, security constraints have to be correctly established in order to avoid unauthorized access. In previous work we defined a Model-Driven based approach for developing a secure DW repository by following a relational approach. Nevertheless, it is also important to define security constraints in the metadata layer that connects the DW repository with the OLAP tools; that is, over the same multidimensional structures that end users manage. This paper incorporates a proposal for developing secure OLAP applications within our previous approach: it improves a UML profile for conceptual modelling; it defines a logical metamodel for OLAP applications; and it defines and implements transformations from conceptual to logical models, as well as from logical models to secure implementation in a specific OLAP tool (SQL Server Analysis Services).This research is part of the following projects: SIGMA-CC (TIN2012-36904), GEODAS-BC (TIN2012-37493-C01) and GEODAS-BI (TIN2012-37493-C03) funded by the Ministerio de Economía y Competitividad and Fondo Europeo de Desarrollo Regional FEDER. SERENIDAD (PEII11-037-7035) and MOTERO (PEII11- 0399-9449) funded by the Consejería de Educación, Ciencia y Cultura de la Junta de Comunidades de Castilla La Mancha, and Fondo Europeo de Desarrollo Regional FEDER

Variations in Chlorella lipid content in commercial and in-lab produced biomass☆

Microalgae appear as a sustainable source of biomass with relevant nutritional qualities. Still, regulatory restrictions currently limit the use of eukaryotic microalgae for human consumption to a short list of species dominated by Chlorella spp. Chlorella biomass contains valuable proteins but also interesting lipids, including polyunsaturated fatty acids (PUFA) ω3 and ω6. The amount of PUFA and the ω6/ω3 ratio vary significantly depending on the species and cultivation trophic mode. While the lipid profils of in-lab produced Chlorella has been widely studied, the variability of lipid content in commercial biomasses is barely described. Here, lipid classes and fatty acid profiles of six commercial biomasses of Chlorella spp. as well as those of lab-produced C. sorokiniana grown in photo-autotrophy and in four mixotrophy conditions were characterized. Results showed significant lipid composition variations between the biomasses, such as the triacylglycerols/glycolipids and ω6/ω3 contents. The ω6/ω3 ratios were lower in photo-autotrophic mode (2.5) while they ranged between 1.3 and 8.9 in commercial biomasses. The free fatty acids level was also variable (1.4% to 17.9% of total lipids). As a consequence, Chlorella lipid content and quality differed significantly, impacting the potential nutritional benefits of the consumption of commercial biomass. Processing and post-processing conditions should therefore be carefully controlled to optimize lipid profiles

Caractérisation et conservation de la diversité bactérienne d’un lait fermenté traditionnel breton, le Gwell en lien avec la préservation d’une race locale de vache, la Bretonne Pie Noir

Le Gwell est un lait fermenté traditionnel spécifique de la Bretagne. Il est obtenu à partir de lait de vaches de race Bretonne Pie Noir, inoculé avec une portion de la fabrication précédente (appelé ferment) sans aucun recours à des levains commerciaux. Les productions de Gwell partagent une texture ferme et onctueuse et un gout frais et acidulé, avec des caractéristiques organoleptiques propres à chaque producteur. Les producteurs sont malheureusement parfois confrontés à la perte de leur ferment et doivent alors avoir recours à la solidarité d’autres producteurs pour réacquérir un ferment opérationnel. Ces pertes de ferments sont un frein au développement de la production de Gwell et donc à la valorisation de lait issu de vaches Bretonne Pie Noir. Cette race emblématique de la Bretagne, caractérisée par une rusticité hors du commun et un lait très riche en matière grasse totalisait au milieu du 19ème siècle près de 900 000 têtes. La modernisation des pratiques agricoles alliée à une orientation productiviste forte a conduit à une quasi extinction de l’espèce, ce qui a conduit à initier en 1976 un programme de sauvegarde de l’espèce. Le nombre de vaches s’élève ainsi aujourd’hui à près de 2500 femelles. La transformation du lait en Gwell est, pour les éleveurs, un moyen de valoriser la qualité du lait de Bretonne Pie Noir en conservant sa valeur ajoutée. Les éleveurs qui transforment le lait en Gwell œuvrent ainsi à la sauvegarde de l’espèce Bretonne Pie Noir, mais aussi à la préservation de la diversité microbienne, du patrimoine et des savoir-faire paysans associés. La caractérisation de l’écosystème microbien du ferment Gwell, pour mieux maitriser sa conservation et sécuriser ainsi la production de Gwell, participe de ce fait au maintien de la race Bretonne Pie Noir. Dans ce contexte notre étude visait à caractériser l’écosystème microbien du Gwell pour sécuriser les souches à l’origine de la typicité du produit. Nous avons ainsi montré que toutes les productions de Gwell avaient une flore bactérienne dominante similaire, composée de deux sous-espèces de la bactérie lactique Lactococcus lactis (subsp. lactis et subsp. cremoris). En fonction des producteurs, le nombre de souches de chaque sous-espèce peut varier avec dans certain cas la présence de Streptococcus thermophilus. De plus, nous avons identifié et caractérisé des souches spécifiques à chaque producteur et montré une forte résilience de l’écosystème pouvant expliquer en partie les différences organoleptiques observées entre les Gwell de différents producteurs

Consommer des aliments fermentés : effet de mode ou réel intérêt santé

National audienc

De l'intérêt de dédier des structures d'accueil et d'étude aux ressources microbiennes d'intérêt alimentaire

Première source de gènes de la planète, les microorganismes représentent une ressource inestimable face aux challenges de durabilité qui sont les nôtres aujourd’hui. Tous les métabolismes y sont représentés et leur biodiversité encore largement sous- explorée est une source clé d’innovation et de valeur ajoutée. Une gestion appropriée des ressources est essentielle pour préserver cette biodiversité et favoriser son utilisation à des fins de développement durable. C'est la fonction première des Centre de Ressources Biologiques (CRB) qui ont pour mission de préserver la biodiversité ex-situ, toutes ressources biologiques confondues, et jouent de ce fait un rôle de conservatoire avec une fonction patrimoniale.On observe depuis plusieurs décennies une diminution drastique de la biodiversité, c'est vrai quelles que soient les ressources biologiques considérées, y compris les espèces microbiennes d'intérêt technologique impliquées dans la fabrication des aliments fermentés. Dès lors, il apparait essentiel de préserver cette diversité microbienne en grande partie responsable de la multiplicité et de la typicité des produits fermentés. C'est un enjeu de taille pour les CRB qui mettent aux services de ces ressources microbiennes une expertise et des outils de caractérisation adaptés. Complémentaire de la conservation in-situ, ils rendent visibles et accessibles ces ressources. Ils permettent en outre de tracer et de formaliser les échanges de matériel biologique et des données associées entre les différentes parties intéressées. Enfin, ils apportent un cadre normatif et règlementaire garant du respect de la propriété intellectuelle et du partage des avantages associé à l'utilisation de ces ressource

Phenotypic variability

The discovery of cheese is a narrative at least 8,000 years old, dating back to the Neolithic era. Yet, after all of these thousands of years we are still finding new ways to combine the same four basic ingredients - milk, bacteria, salt, and enzymes - into new and exciting products with vastly different shapes, sizes, and colors, and equally complex and varied tastes, textures, and, yes, aromas. In fact, after a long period of industrialized, processed, and standardized cheese, cheesemakers, cheesemongers, affineurs, and most of all consumers are rediscovering the endless variety of cheeses across cultures.The Oxford Companion to Cheese is the first major reference work dedicated to cheese, containing 855 A-Z entries on cheese history, culture, science, and production. From cottage cheese to Camembert, from Gorgonzola to Gruyère, there are entries on all of the major cheese varieties globally, but also many cheeses that are not well known outside of their region of production. The concentrated whey cheeses popular in Norway, brunost, are covered here, as are the traditional Turkish and Iranian cheeses that are ripened in casings prepared from sheep's or goat's skin. There are entries on animal species whose milk is commonly (cow, goat, sheep) and not so commonly (think yak, camel, and reindeer) used in cheesemaking, as well as entries on a few highly important breeds within each species, such as the Nubian goat or the Holstein cow. Regional entries on places with a strong history of cheese production, biographies of influential cheesemakers, innovative and influential cheese shops, and historical entries on topics like manorial cheesemaking and cheese in children's literature round out the Companion's eclectic cultural coverage.The Companion also reflects a fascination with the microbiology and chemistry of cheese, featuring entries on bacteria, molds, yeasts, cultures, and coagulants used in cheesemaking and cheese maturing. The blooms, veins, sticky surfaces, gooey interiors, crystals, wrinkles, strings, and yes, for some, the odors of cheese are all due to microbial action and growth. And today we have unprecedented insight into the microbial complexity of cheese, thanks to advances in molecular biology, whole-genome sequencing technologies, and microbiome research. The Companion is equally interested in the applied elements of cheesemaking, with entries on production methodologies and the technology and equipment used in cheesemaking.An astonishing 325 authors contributed entries to the Companion, residing in 35 countries. These experts included cheesemakers, cheesemongers, dairy scientists, anthropologists, food historians, journalists, archaeologists, and on, from backgrounds as diverse as the topics they write about. Every entry is signed by the author, and includes both cross references to related topics and further reading suggestions. The endmatter includes a list of cheese-related museums and a thorough index. Two 16-page color inserts and well over a hundred black and white images help bring the entries to life.This landmark encyclopedia is the most wide-ranging, comprehensive, and reliable reference work on cheese available, suitable for both novices and industry insiders alike.absen