Structural and antigenic properties of thermally treated gluten proteins

Abstract

The present study is focused on heat-induced changes in the structure and antigenic properties of gluten proteins. The thermal dependent behavior of glutenins and gliadins was analyzed through intrinsic fluorescence parameters, phase diagram method, and quenching experiments using acrylamide and iodide. Unfolding events were registered in the phase diagram of glutenins up to 80°C, followed by partial refolding and aggregation at even higher temperatures. The gliadins structure appeared to be progressively disorganized with the temperature increase up to 100°C. The thermally denatured proteins exposed different functional groups leading to 64% reduction of the antigenic properties. No significant differences in terms of residual antigenicity were observed among samples treated at temperatures over 60°C for 20 or 60min. Finally, changes in the linear epitopes exposure and location of conformational epitopes of α-/β-, γ- and ω5-gliadins were highlighted after performing molecular dynamics simulations to heat the proteins from 25°C to 100°C.

Keywords: Antigenicity; Conformational changes; Gliadins; Glutenins.