The reduction in the immunoglobulin G and immunoglobulin E binding capacity of β-lactoglobulin via spray-drying technology

Bovine beta-lactoglobulin (beta-LG) is the major allergen in milk powder. The IgG/IgE binding capacity and structural characteristics of beta-LG after spray drying in the presence or absence of alpha-lactose at 120 and 180 degrees C were investigated by ELISA and mass spectrometry. At a drying temperature of 120 degrees C, no change was found in the IgG/IgE binding capacity of beta-LG and no change was observed in free amino group content, fluorescence intensity, or detectable glycation. At a drying temperature of 180 degrees C, aggregation of beta-LG occurred, leading to a decrease in the IgG/IgE binding capacity. When alpha-lactose was also present, 7 lysine side-chains in beta-LG were modified by glycation and the IgG/IgE binding capacity was further decreased. Therefore, the glycation and structural changes in beta-LG were responsible for the reduction in the IgG/IgE binding capacity during high temperature (180 degrees C) spray drying.