Rheology of Buildup, Breakdown, and Rebodying of Acid Casein Gels

Dynamic oscillations were measured during in situ buildup and breakdown of acid casein gels induced by glucono-δ-lactone at varying temperatures and skim milk solids concentrations. The gel structure was gradually broken down by continuous oscillation at high strains. Using high strains (up to .8), gel moduli were lowered to a few percentages of their original value with no wall slip problems. No equilibrium values were found for either buildup or breakdown. The time course of buildup and rebodying was complex, but different gels were affected by shear in the same way in relation to their initial values. Strain was the main rate determining parameter.