Apparent voluminosity of casein micelles determined by rheometry

The voluminosity of casein micelles was studied by means of static rheometry. In concentrated casein micelle suspensions with fluid-like flow properties to random-close packing, the reduced viscosity was obtained and linked via the Krieger–Dougherty model of volume fraction effect. The temperature dependency of hydration was fitted in a wide temperature (5°C⩽ϑ⩽35°C) and mass fraction range (0.01⩽w⩽0.160.01⩽w⩽0.16). The results of our study suggested that the voluminosity of casein micelles decreased with increasing temperature and asymptotically reached a plateau (ϑ>30°C) as a consequence of the protein swelling and decreasing water immobilization. The obtained apparent voluminosity of native casein micelles dispersed in UF permeate was 5.0 ml g−1 at 5°C, 4.1 ml g−1 at 20°C, and 3.7 ml g−1 at 35°C.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (166 K)Download as PowerPoint slideHighlights► We modelled the apparent voluminosity based on rheological measurements. ► Casein micelle suspensions will fit Krieger–Dougherty and voluminosity models. ► The voluminosity–temperature relationship follows a continuous function. ► The voluminosity of casein micelles decreases with increasing temperature (5–35 °C).