FILMS BASED ON KEFIRAN, AN EXOPOLYSACCHARIDE OBTAINED FROM

PIERMARÍA, J.; PINOTTI, A.; GARCIA, M.A.; ABRAHAM, A.

FOOD HYDROCOLLOIDS

Elsevier

Año: 2008 vol. 23 p. 684 - 690

0268-005X

Kefiran, an exopolysaccharide produced by microorganisms present into the kefir grains, is a glucogalactan that has several health promoting properties. In the present work the ability of kefiran to form films and the effect of glycerol addition at different concentrations on film properties was evaluated. Kefiran was able to form films at concentration ranging from 5 to 15g/kg. The concentration 10g/kg was selected because the films were easily removed from the plate. All film-forming solutions exhibited a pseudoplastic behaviour; glycerol addition did not modify the solution rheological properties. Kefiran films exhibited differential solubility characteristics, at the different assayed temperatures. SEM showed smooth surfaces, exhibiting plasticized films more compact structures than those of unplasticized ones. These films exhibited good water vapor barrier properties and the addition of 25 g of glycerol per 100g of polysaccharide allowed to obtain the optimum value (4.09 × 10-11 g/m.s.Pa). Films without glycerol were brittle and rigid since they showed high elastic modulus and tensile strength values and low deformation at break. Besides, glycerol addition led to elongation values extremely high, allowing flexibilities comparable to those of synthetic materials.