We have experience in the characterization of the potential health benefits of lactic acid bacteria (LAB) producing either dextran or the riboflavin vitamin B2. This recent line of research is based on the working hypothesis that combining dextran- and vitamin B2-producing LAB could generate fermented foods, enriched in riboflavin (RF) and with immuno-stimulating properties, and which would also act as a vehicle to deliver probiotic LAB to the human gut, where they might release vitamin Bafter their ingestion. Such functional foods could benefit various population segments (e.g. pregnant women, alcohol abusers, elderly people, immunocompromised people and patients with liver disease or long-lasting infections) that may require a higher RF intake than that supplied by a diet that is adequate for healthy people. In addition to the CIB group, the groups led by Dr. Mª Teresa Dueñas from the Basque country University, Prof. Giuseppe Spano from Foggia University (Foggia, Italy), Dr. Jean Guy LeBlanc from Centro de Referencia de Lactobacilos (Tucumán, Argentina) and Dr. Kihal from Oran University (Oran, Argelia) will also participate in the development of this research line, which falls within the project RTI2018-097114-B-I00.

For this purpose, we are making use of three different collections of LAB isolated from either cereal-based or dairy products: i) the PANBAL collection of the group of Dr. Mercedes Tamame at Instituto de Biología Funcional y Genómica (IBFG, CSIC, Salamanca, Spain), which includes Lactobacillus, Leuconostoc and Weisella strains isolated from bread dough provided by Spanish bakeries, artisan sourdoughs, and laboratory made sourdoughs, developed with traditional flours, or innovative low- (Tritordeum) or free-gluten flours (maize, rice, quinoa, etc.) ii) the BFBL collection of the group of Drs. Carmen Peláez and Teresa Requena at the Instituto de Investigación en Ciencias de la Alimentación (CIAL, CSIC, Madrid, Spain), which includes strains isolated from dairy products and belonging, among others, to the Leuconostoc genus; and iii) the Algerian LAB collection composed of strains belonging to the Leuconostoc, and Weisella genera and isolated from camel milk and leban, an Algerian buttermilk drink.

Development of this research line includes testing of LAB from these three collections with respect to their capacity to synthesize RF and dextran. Next, the technological and probiotic traits of those strains producing both metabolites will be analyzed and RF-overproducing mutants will be selected from the most suitable strains. 

A final goal of this research line will be the production and testing of three different vitamin B2- and dextran-enriched functional foods that could benefit the above-mentioned population segments of developed countries, namely: i) a bread fermented in the presence of a mixture of two well-characterized LAB strains, one of which overproduces RF and the other renders large amounts of dextran; ii) a dairy product fermented in the presence of a dextran-producing LAB (to be selected in the project) which also overproduces vitamin B2 and has probiotic traits; and iii) a dairy product elaborated by adding to the fermented milk a concentrated suspension carrying a potentially probiotic RF-overproducing LAB (to be selected in the project) together with its dextran product, which will act as a vehicle for the bacterium to reach the human gut. Moreover, the dairy products will be used for tracking the gastrointestinal survival of LAB and functionality in vitro in a human digestive tract simulator and in vivo in murine models. Achievement of this goal will be the “proof of concept” for extending the research to the manufacturing of further functional foods suitable for population groups with distinct nutritional requirements, such as vegans, sufferers of coeliac disease or intolerance to lactose, and others who suffer from inflammatory bowel diseases. Importantly, accomplishment of the proposed research will provide basic knowledge on the regulation of the biosynthesis and export of RF by these LAB, which might be applied in the future to obtain LAB strains secreting even higher levels of vitamin B2. Finally, this research line will provide us with a characterized LAB collection that should be suitable for manufacturing of these types of specific functional foods.


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