Shear, heat and pH induced conformational changes of wheat gluten - Impact on antigenicity

Processing can induce conformational changes of food proteins depending on the conditions used that may affect their antigenicity. This study investigated the effect of pH (3,5,7) temperature (80,90,100 degrees C) and shear (500,1000,1500 s(-1)) on the conformational changes (surface hydrophobicity, FTIR, SDS-PAGE and thiol content) of gluten in relation to its antigenicity (determined by Enzymelinked Immunosorbent Assay). Overall, at pH 3, up to 90 degrees C, conformational changes and possible burial of some antigenic hydrophobic residues resulted in reduction of antigenicity to one-third that of control. Further heating to 100 degrees C caused increase in antigenicity due to exposure of some hidden epitopes. However, at pH 5 and 7, the antigenicity declined only at 100 degrees C due to modification in thiol content and related structural changes causing destruction and/or masking of some epitopes. Shear alone had no effect on antigenicity of gluten but could have a synergistic influence at pH 7 and 100 degrees C. Crown Copyright (C) 2015 Published by Elsevier Ltd. All rights reserved.