Static and Dynamic Scattering of β-Lactoglobulin Aggregates Formed after Heat-Induced Denaturation at pH 2

Abstract

The structure and internal dynamics of β-lactoglobulin aggregates formed after heat-induced denaturation at pH 2 and different ionic strengths were investigated using light, neutron, and X-ray scattering. Polydisperse aggregates are formed with a rigid rodlike local structure with mass per unit length close to that of a string of β-lactoglobulin monomers but with a somewhat larger diameter. The persistence length decreases with increasing ionic strength from more than 600 nm at 0.013 M to 38 nm at 0.1 M. At ionic strengths of 0.1 and 0.2 M, a self-similar structure with fractal dimensions of 1.8 and 2.0 is seen by using light scattering. The concentration dependence of the static structure factor and the internal dynamics are close to those of flexible linear chains. In contrast, a rigid behavior is observed at lower ionic strength (0.03 and 0.013 M). The persistence length of aggregates formed at 0.013 M is reduced after dilution in 0.1 and 0.2 M ionic strength solvents but remains larger than that of aggregates formed and diluted in 0.1 and 0.2 M. The ionic strength of formation is thus a determining factor for the structure. At pH 2, there is no evidence for a two-step aggregation process as was observed at pH 7.

Influence of Run Time and Aging on Fouling and Cleaning of Whey Protein Deposits on Heat Exchanger Surface

“…Since the deposit chemical composition would not change during heating so the same deposit experiences 'aging' in essence. The possible explanation for this is that heating the whey protein solutions above 60°C, provokes complex changes of the molecular conformation and undergo denaturation (Aymard et al, 1999). Similarly as discussed in the HIWPG formation, this leads the protein molecules to exhibit hydrophobic areas on its surface (Cantor and Schimmel, 1980;Verheul and Roef, 1998;Galani and Apenten, 1999).…”

“…The partially denatured proteins aggregate via the exposed covalent disulfide bonds (Galani and Apenten, 1999;Perez-gago and Krochta, 2001) and eventually precipitate on the heat exchange surface. The kinetics of aggregation and the aggregation rate are influenced by the heating conditions (Aymard et al, 1999). With increasing heating time, the formation of strong covalent disulfide bonds may become more extensive within the deposit.…”

Self-assembly in aqueous solution of a modified amyloid beta peptide fragment

“…DLS has already been used to study the formation of amyloid fibres from many peptides and fibrils, such as β-lactoglobulin [8][9][10]. The field correlation function corresponding to a solution of protein fibres with several tens of nanometers in length presents a single exponential behaviour, corresponding to a single relaxation mode with a well-defined hydrodynamic radius.…”

The Critical Aggregation Concentration of β-Lactoglobulin-Based Fibril Formation

“…They can be formed from various food proteins like egg white proteins [1][2][3][4][5] , soy proteins 6 , and whey proteins [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] . The fibrils can, for example, be used as structurants and thickeners to give food products a specific texture.…”