Influence of the ionic strength on the heat-induced aggregation of the globular protein beta-lactoglobulin at pH 7.
The influence of the ionic strength on the structure of beta-lactoglobulin aggregates formed after heating at pH 7 has been studied using static and dynamic light scattering. The native protein depletion has been monitored using size exclusion chromatography. Above a critical association concentration (CAC) well-defined clusters are formed containing about 100 monomers. The CAC increases with decreasing ionic strength. The so-called primary aggregates associate to form self similar semi-flexible aggregates with a large scale structure that is only weakly dependent on the ionic strength. The local density of the aggregates increases with increasing ionic strength. At a critical gel concentration, Cg, the size of the aggregates diverges. Cg decreases from 100 g/l without added salt to 1 g/l at 0.4M NaCl. For C > Cg the system gels except at high ionic strength close to Cg where the gels collapse under gravity and a precipitate is formed.
Baussay
Karine
K
Polymères, Colloïdes, Interfaces, UMR CNRS, Université du Maine, Av. Olivier Messiaen 72085 Le Mans Cedex 9, France.
Bon
Christel Le
CL
Nicolai
Taco
T
Durand
Dominique
D
Busnel
Jean-Pierre
JP
D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007782:Lactoglobulins / Q000737:chemistry*; D009994:Osmolar Concentration
D007782:Lactoglobulins