Biological and technological functionality of kefiran

ABRAHAM A. G.

San Miguel de Tucumán

Simposio; III Simposio Internacional de Bacterias Lácticas. II Encuentro Red BAL; 2009

Cerela

Polysaccharides are widespread macromolecules used to modify and improve texture of food products. Recently, scientific research has focused on health promoting properties of glucidic compounds in addition to the traditional nutritional aspect. Nowadays, health promoting properties of glucidic compounds are by far the most underexploited and promising field. Those functional properties include their ability to be used in food as prebiotics, dietary fibres or fat replacers. Certain LAB excrete a wide diversity of polysaccharides with respect to their monomer composition, molecular weight (MW), structure, and functionalities. LAB producing EPS are being used for improving the rheological properties of dairy products although the use of these polymers as isolated ingredients is still limited due to their low production An interesting alternative is the use of kefiran, the polymer produced by LAB in kefir grains the extraction method of kefiran from grains was simple with a good yield of extraction and that deproteinized whey could be utilized as substrate for kefir grain biomass production             Kefiran, a high-MW EPS produced by microorganisms present in the grains of the Kefir fermented milk, has displayed novel applications in the food industry. Kefiran, which has a Newtonian behaviour in diluted solutions but pseudoplastic at high concentrations, improves the viscosity and viscoelastic properties of acid milk gels. This EPS is also able to form gels at low temperatures, and brittle and rigid films. However, glycerol addition confers it extremely high elongation values, allowing comparable flexibilities to those of synthetic material. In addition, several health-promoting properties of kefiran such as immunomodulation or epithelium protection have been reported. Furthermore, Kefiran has the ability to antagonize biological activity of Bacillus cereus on Caco-2 cells thus providing new perspectives for the role of this bacterial EPS in functional foods.