Interactions of (β‐Lactoglobulin and High‐methoxyl Pectins in Acidified Systems

The interactions that occur when β‐lactoglobulin (β‐lg) is mixed with a high‐methoxyl pectin (HMP) and a modified pectin (mHMP, modified using plant pectinesterase) were examined at pH 3.8. Whereas soluble aggregates formed in β‐lg‐HMP, β‐lg‐mHMP precipitated upon mixing. β‐lg‐HMP mixtures showed soluble aggregates with larger hydrodynamic diameters when heated at 65°C than when heated at 90°C. β‐lg‐HMP mixtures adjusted to pH 6.0 after heating showed that the aggregates formed at 65°C could be dissociated, but the complexes were not reversible after heating at 90°C. A similar effect also was observed when resuspending the°‐lg‐mHMP precipitates at pH 6.0. The behavior of the 2 pectins was attributed to their differences in charge distribution.