The Fate of IgE Epitopes and Coeliac Toxic Motifs during Simulated Gastrointestinal Digestion of Pizza Base

Abstract

Understanding how food processing may modify allergen bioaccessibility and the evolution of immunologically active peptides in the gastrointestinal tract is essential if knowledge-based approaches to reducing the allergenicity of food are to be realised. A soy-enriched wheat-based pizza base was subjected to in vitro oral–gastro–duodenal digestion and resulting digests analysed using a combination of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectrometry (MS). The digestion profile of pizza base resembled that of bread crust where higher temperatures during baking reduced protein solubility but still resulted in the generation of a complex mixture of peptides. MS profiling showed numerous peptides carrying IgE epitopes, and coeliac toxic motifs were in excess of 20–30 residues long and were only released after either 120 min of gastric digestion or a combination of gastric and duodenal digestion. In silico prediction tools showed an overestimated number of cleavage sites identified experimentally, with low levels of atypical peptic and chymotryptic cleavage sites identified particularly at glutamine residues. These data suggest that such alternative pepsin cleavage sites may play a role in digestion of glutamine-rich cereal foods. They also contribute to efforts to provide benchmarks for mapping in vitro digestion products of novel proteins which form part of the allergenicity risk assessment.

Analytical Methods for Allergen Control in Food Processing

“…MS is particularly suited for the detection of peptides or polypeptides of “hydrolysed” allergens. This is well demonstrated in [ 1 ], in which IgE epitopes and coeliac toxic motifs are detected in the digesta of soy-enriched wheat-based pizza bases. A new MS method was developed and applied to the analysis of 14 different α-amylase/trypsin inhibitors in wheat [ 22 ].…”

“…Food allergy and food-related anaphylaxis have become a growing public health and food safety issue worldwide. The World Allergy Organization (WAO) estimated that 220–250 million people would live with food allergies, based on the reported prevalence of 5–8% in children and 1–2% in adults [ 1 ]. Without a practical treatment and cure for food allergy currently available, the diligent avoidance of allergenic foods together with the prompt treatment of symptoms is the best management option available to allergic individuals [ 2 ].…”