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

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.