Shear-sensitive casein micelle suspensions for future Rheo-SANS experiments

by Prof. Roland Gebhardt

Monday 13 Nov 2017, 14:30 → 15:30 Europe/Berlin

HS 3 (Physics Department)

Caseins from cow milk are used as raw material for several food products such as yoghurt or cheese or as additives for protein enrichment. They form so-called “casein-micelles”, colloidal structures of spherical shape with many structural similarities to microgels (e.g. architectural versatility depending on conditions, permeability and deformability) [1]. Caseins are prone to self-0 - 10^3 s^-1) occur [2,3] while higher shear rates (10^3 - 10^6 s^-1) and temperatures (50 - 75 °C) are used during homogenization [3,4]. Both variables affect the rheological properties of casein suspensions [5]. However, little is known about the relationships between flow behaviour and structures in casein micelle suspension. We will report in detail on X-ray, Raman- and light scattering experiments in combination with elongational flow and compression, which we used to probe the soft properties of casein micelles. Furthermore, we present viscosity curves of casein micelles measured over a broad temperature and concentration range and the corresponding analysis with regard to similarities between casein micelles and microgels [6,7,8].

[1]   F. A. Plamper, W. Richtering (2017) Accounts of chemical research, 50, 131
[2]   Dorian Weipert and Felix Escher (1993) Rheologie der Lebensmittel. Behr, Hamburg
[3]   Regional Activity Centre for Cleaner Production (RAC/CP), Prevention of        pollution in the Dairy industry, (2002)
[4]   H. P. Schuchmann, and H. Schuchmann (2012) Lebensmittelverfahrenstechnik     Wiley-VCH
[5]   S. Nöbel, K. Weidendorfer, J. Hinrichs (2012) Journal of Colloid and Interface Science, 386, 174
[6]   C. L. A. Berli and D. Quemada (2000) Langmuir 16(21), 7968
[7]   M. L. Olivares, C. L. A. Berli, and S. E. Zorrilla (2013) Colloids and Surfaces A,   436, 337

Coffee and cookies will be served! We hope to see you all there.