Effect of Ultrasound-Assisted Luteolin Treatment on the Structure and Allergenicity of β-Lactoglobulin

Bovine β-Lactoglobulin (BLG) induces severe cow’s milk allergy. This research investigated the effect of ultrasound-assisted luteolin (LUT) treatment on the structure and allergenicity of BLG. The structure of the treated BLG was characterized by Fourier transform infrared (FTIR) spectroscopy, circular dichroism (CD) spectroscopy, ultraviolet (UV) absorption spectroscopy and fluorescence spectroscopy, and its allergenicity was evaluated by enzyme-linked immunosorbent assay (ELISA) and cell experiments. It was found that the major interaction force between BLG and LUT was hydrophobic interaction both before and after ultrasonic treatment. Ultrasound-assisted LUT treatment significantly altered the secondary and tertiary structures of BLG, and reduced the IgE-binding ability and the release of interleukin-6, interleukin-4 and histamine from KU812 cells. Therefore, ultrasound-assisted LUT treatment changes the conformational epitope of BLG, reducing its allergenicity, and the best effect can be achieved by secondary ultrasound-assisted LUT treatment.