INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Structural Investigations of Sodium Caseinate micelles in complex environments
Autor/es:
CRISTIÁN HUCK IRIART; MARIA LIDIA HERRERA; ROBERTO J. CANDAL; CRISTIANO L.P. OLIVEIRA; IRIS L. TORRIANI
Lugar:
Campinas
Reunión:
Congreso; 22a Reunion Anual de Usuarios del LNLS; 2012
Resumen:
The most frequent destabilization mechanisms in Sodium Caseinate (NaCas) emul-
sions are creaming and flocculation. Coarse or fine emulsions with low protein con-
tent destabilize mainly by creaming. If migration mechanism is suppressed, floc-
culation may become the main mechanism of destabilization. Small Angle X-Ray
Scattering (SAXS) technique was applied to investigate sodium caseinate micelles
structure in different environments. As many natural products, Sodium Caseinate
samples have large polydisperse size distribution. The experimental data was an-
alyzed using advanced modeling approaches. The Form Factor for the Caseinate
micelle subunits was described by an ellipsoidal core shell model and the structure
factor was split into two contributions, one corresponding to the particle-particle
interactions and another one for the long range correlation of the subunits in the
supramolecular structure. For the first term the hard sphere structure factor using
the Percus-Yevick approximation for closure relation was used and for the second
term a fractal model was applied.
Three concentrations of sodium Caseinate (2, 5 and 7.5 %wt.) were measured in
pure water, sugar solutions (20 %wt.) and in three different lipid phase emulsions
containing 10 %wt. sunflower seed, olive and fish oils. Data analysis provided an
average casein subunit radius of 4 nm, an average distance between the subunits of
around 20nm and a fractal dimension value of around 3 for all samples. As indicated
by the values of the correlation lengths for the set of studied samples, the casein
aggregation is strongly affected by simple sugar additions and it is enhanced by
emulsion droplets hydrophobic interaction. As will be presented, these nanoscale
structural results provided by scattering experiments is consistent with macroscopic
results obtained from several techniques, providing a new understanding of NaCas
emulsions.