Phase Separation and Association of Globular Protein Aggregates in the Presence of Polysaccharides: 2. Heated Mixtures of Native β-Lactoglobulin and κ-Carrageenan

Aqueous solutions of globular proteins (β-lactoglobulin) at pH 7 and 0.1 M NaCl were heated in the presence of various concentrations of polysaccharide (κ-carrageenan). The fraction of unaggregated proteins was determined as a function of heating time with size exclusion chromatography. The rate at which the proteins aggregate is independent of the polysaccharide concentration at least up to 9 g/L κ-carrageenan. The protein aggregates were characterized using light scattering. At modest concentrations (up to 1 g/L) the presence of κ-carrageenan accelerates the growth of the aggregates and therefore the gel formation, but the structure of the aggregates is not modified. At higher concentrations κ-carrageenan induces phase separation of protein aggregates.