Structural changes and allergenic properties of β-lactoglobulin upon exposure to high-intensity ultrasound.
METHODS
The aim of this work was to investigate the effects of high-intensity ultrasound (sonication), on the structure and allergenicity of the major cow's milk allergen, beta-lactoglobulin (BLG).


RESULTS
Structural changes upon sonication of BLG were monitored by circular dichroism spectroscopy, tryptophan emission fluorescence, hydrophobic dye and retinol binding, as well as digestibility and phenol-oxidase cross-linking capacity. Allergenicity was monitored in individual patients' sera, basophil activation test, and skin prick testing in 41 cow's milk allergy patients. Uncontrolled local temperature changes induced modifications in BLG secondary structure accompanied by formation of dimers, trimers, and oligomers of BLG that were more digestible by pepsin and had reduced retinol binding. Controlled temperature conditions induced changes in secondary structure of BLG without causing formation of oligomers, or changing protein's capacity to bind retinol. Both sonicated forms of BLG had more exposed hydrophobic surfaces than native BLG and underwent facilitated cross-linking reaction with phenol-oxidase. Sonication had a minor effect on IgE-binding properties of BLG.


CONCLUSIONS
Sonication-induced structural changes in major whey allergen were not clinically significant in cow's milk allergy patients. Ultrasound can be a safe procedure for dairy processing as it maintains the nutritional value and does not increase allergenic potential of BLG.
Faculty of Chemistry, Department of Biochemistry, University of Belgrade, Belgrade, Serbia.
Dragana
D
Stanic-Vucinic
Marija
M
Stojadinovic
Marina
M
Atanaskovic-Markovic
Jana
J
Ognjenovic
Hans
H
Grönlund
Marianne
M
van Hage
Raija
R
Lantto
Ana I
AI
Sancho
Tanja Cirkovic
TC
Velickovic
D000485:Allergens / Q000737:chemistry / Q000276:immunology; D000817:Anilino Naphthalenesulfonates; D000818:Animals; D001491:Basophils / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D002850:Chromatography, Gel; D002942:Circular Dichroism; D003432:Cross-Linking Reagents; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007223:Infant; D007782:Lactoglobulins / Q000737:chemistry* / Q000276:immunology* / Q000528:radiation effects*; D008297:Male; D008892:Milk / Q000737:chemistry; D016269:Milk Hypersensitivity / Q000175:diagnosis / Q000276:immunology*; D014442:Monophenol Monooxygenase / Q000378:metabolism; D010434:Pepsin A / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012882:Skin Tests; D013010:Sonication / Q000379:methods; D013696:Temperature
C515594:8-anilino-1-naphthalenesulfonic acid; D000485:Allergens; D000817:Anilino Naphthalenesulfonates; D003432:Cross-Linking Reagents; D007782:Lactoglobulins; D007073:Immunoglobulin E; D014442:Monophenol Monooxygenase; D010434:Pepsin A