Caseinomacropeptide modifies the heat-induced denaturation aggregation process of [i]β-lactoglobulin[/i]
Résumé
The effect of caseinomacropeptide (CMP) concentration on the kinetics of denaturation of b-lactoglobulin (b-Lg) and on the size and structure of the heat-induced aggregates was investigated over a wide range of pH (3.0e6.7) and temperature (65e95 C). Irrespective of pH and heating temperature, CMP increased the rate of b-Lg denaturation. When b-Lg and CMP were negatively charged (i.e., at pH 6.7), increasing CMP concentration hindered aggregate formation; the aggregates had a smaller hydrodynamic diameter and the protein solution turbidity decreased. However, when b-Lg and CMP were oppositely charged (i.e., at pH 4.0), CMP promoted aggregate formation and large particles (>5 mm) were formed on heating. Nevertheless, the covalent aggregates constituting these large particles were of smaller size than those formed on heating b-Lg in the absence of CMP. At pH 4.0, CMP induced the formation of large particles when added in a solution of preformed aggregates of b-Lg.