Defining the conditions for heat-induced gelation of a caseinate-stabilized emulsion

Depending on pH and calcium ion content, a concentrated emulsion (45 vol.% oil) stabilized by sodium caseinate (8.1 wt.% in aqueous. phase) as sole emulsifying agent can be made to transform from a liquid-like emulsion at less than or equal to 25 degreesC to a solid-like emulsion gel by heating to a temperature in the range 30-45 degreesC. The gelation process can be described as thermoreversible when characterized in terms of viscometry measurements made at a reasonably high applied shear stress (40 Pa). It has been established that reversible heat-induced emulsion gelation does not occur for calcium ion concentrations below 10 mM in the aqueous phase or pH values outside the range 5.4 < pH <= 6.4. (C) 2002 Published by Elsevier Science B.V.