Apparent voluminosity of casein micelles in the temperature range 35–70 °C

Abstract

Casein micelles are basic units of dairy matrices that can be aggregated by reducing their electrostatic repulsion or by surface modifications. Studying casein micelles in terms of a colloidal suspension demands of a preferably complete physico-chemical characterisation. Process control in dairy technology as well as mechanistic models that explain the formation and structure of dairy products build on the specific hydration of the casein micelles. The effect of the temperature on the voluminosity of native casein micelles at pH 6.6–6.7 was investigated using rheometry covering a wide range of temperatures and mass fractions. Increasing temperature resulted in a constant decrease of the voluminosity up to 70 °C. A quadratic polynomial was tested to fit the temperature dependency the best. The apparent voluminosity of casein micelle suspensions was determined with 4.0 mL g−1 at 35 °C, 3.6 mL g−1 at 50 °C, and 3.5 mL g−1 at 70 °C.