Kefiran improves rheological properties of glucono delta lactona induced skim milk gels.

RIMADA, PABLO; ABRAHAM, ANALIA G

INTERNATIONAL DAIRY JOURNAL

Lugar: Elsevier Ltd; Año: 2006 vol. 16 p. 33 - 39

0958-6946

The effects of addition of kefiran, the exopolysaccharide found in kefir grains, on apparent viscosity (Zapp) and dynamic rheological properties of chemically acidified skim-milk gels were investigated. The effect of a heat treatment on kefiran–skim milk mixture was also evaluated. Gels without kefiran showed a pseudoplastic thixotropic behaviour with a small area enclosed between the up and down curves. The addition ofkefiran significantly (Pp0.05) increased the hysteresis loop and the viscosity ofthe gels.Apparent viscosity ofgels increased with kefiran concentration up to 300 mgL
1. Further addition did not modify significantly (Pp0.05) the apparent viscosity ofgels. Gels prepared from heat treated milk–kefiran mixtures showed a significantly higher visc app than the ones that were prepared without a heat treatment at all kefiran concentrations assayed. The elastic modulus (G0) and the viscous modulus (G00) ofgels prepared with heat treated milk mixes increased with increasing kefiran concentration, without influencing the loss tangent (G00/G0). The present results demonstrate that viscosity and viscoelastic properties ofacid gels were improved by kefiran addition suggesting a possible application ofthis natural polysaccharide as an alternative thickening agent in dairy products.