Rheological methods to analyse the thermal aggregation of calcium enriched milks

MEZA, BE; ZORRILLA, SE; OLIVARES, ML

INTERNATIONAL DAIRY JOURNAL

ELSEVIER SCI LTD

Año: 2019 vol. 97 p. 25 - 30

0958-6946

The colloidal state of calcium enriched milks during heating and its microstructures were analyzed through the interpretation of rheometric data with the Brownian aggregation theory, which can be considered as complementary of the currently used methods. Viscosity was measured at 100 s-1 through temperature and time sweeps. It was observed that from 25 to 60°C, viscosity slowly decreased as temperature increased; above60°C, viscosity sharply increased at different temperatures depending on the amount of CaCl2. From time sweeps, the aggregation of casein micelles was described through the Smoluchowski theory. The addition of CaCl2 at concentrations of 20-30 mmol kg-1 decreased the stability factor 5 to 6 orders of magnitude compared to non-enriched milk. Values of the fractal dimension indicated that aggregation yields disordered aggregates occluding high amounts of solvent. The methodology described may help to analyze the colloidal stability and the structures when different calcium salts are used for enrichment.