Omega-3 Fatty Acids Used as Cross-Linkers to Reduce Antigenicity of Wheat Flour

Abstract

Alpha-linolenic, docosahexaenoic and eicosapentaenoic acids were shown to cross-link hydrolyzed gluten in digested flour, thus reducing immunoreactivity of flour and bread. Residual immunoreactivity in cross-linked flour samples was determined with human coeliac immunoglobulin G (IgG) at 35–45% and 10–30%, respectively, for subtilisin and collagenase treatment. Analogous transglutaminase-cross-linked flour samples exhibited residual immunoreactivity at 34 and 15%. Chemical cross-linking reagents – polyethylenimine and diethanolamine – decreased it below 20%. Similar results were obtained when rabbit anti-QQQPP (Gln-Gln-Gln-Pro-Pro) IgG were used as detection antibodies. Flour samples underwent fermentation, thermal processing and simulated digestion. Residual immunoreactivity in bread made of flour cross-linked with fatty acids was determined with human IgG at 10–70% and 3–60%, respectively, for subtilisin and collagenase treatment. At the same time, transglutaminase cross-linking yielded residual immunoreactivity of bread at 10–20%. Rabbit antibodies did not indicate significant differences between samples of collagenase-treated bread, whether cross-linked with transglutaminase or fatty acids. Practical Applications Given the popularity of cereal-based products in our diet, gluten intolerance is a significant issue. The antigenicity of flour proteins can, to a great extent, be neutralized through hydrolysis and cross-linking with polyunsaturated omega-3 fatty acids. Antigenic amino acid structures are bound deep into the complex surface of the cross-linked protein and are rendered unrecognizable to the consumer's immune system. Cross-linked proteins in flour and bread provoke milder allergy symptoms, allowing dietary restrictions to be reduced. These natural reagents could potentially be a valuable tool in efforts to produce safer bakery products. We propose that they could be used in combination with other known cross-linkers to improve the overall antigenic effect of food processing.