Proteomic characterization and in-silico immunogenicity assessment of prototype durum wheat bread samples for potential tolerability by wheat allergic consumers

Wheat is one of the most important and widely consumed cereals in the world, and it is the preferred choice for bread and pasta making. The wheat proteins consist of two main classes: albumin/globulin and storage proteins [1]. In addition to their functional and rheological properties, wheat proteins may activate several inflammatory responses in susceptible individuals, with different immunological pathways, such as celiac disease, atopic dermatitis, urticarial and wheat allergies [2]. Wheat allergens are well characterized and the most relevant include gliadins, glutenins, ?-amylase, and ?-amylase/trypsin/subtilisin inhibitor, among others [3]. Previous investigations carried out in our laboratories on selected durum wheat genotypes proved that the expression of toxic/immunogenic epitopes relevant to either celiac disease and wheat allergy is variety-dependent and can be clearly disclosed by advanced proteomic approaches [4]. In particular, a set of genotypes with a differential expression of toxic/immunogenic epitopes compared to commercial semolina was identified and fully characterized in terms of proteomic profile of the raw flour [4]. Grounding on this knowledge, the aim of the current study was to prepare and characterize the proteomic profile of potentially hypoallergenic wheat based products, such as bread, starting from selected durum wheat genotypes with confirmed differential immunogenicity. In order to achieve this goal an ad hoc microbiological treatment for detoxification has been applied based on selected Lactobacillus strains and fungal proteases. Among the Triticum turgidum wheat genotypes previously characterized [4], three varieties were tested for the scope, namely Colosseo (spp.durum), Neolatino (spp.durum) and PI56263 (spp. turgidum) and prototype bread samples were produced at lab-scale, preparing, in parallel, hydrolyzed and control samples for comparative purposes. Bread samples were characterized by advanced proteomic approach by using high-resolution tandem mass spectrometry coupled to bioinformatics tools for sequence identification and in-silico evaluation of the residual allergenicity. The online platform IEDB [5] was queried to trace the presence of resistant immunogenic epitopes in the hydrolyzed bread samples. Noteworthy, no immunogenic epitopes were detected in the PI56263 bread sample; a reduction of the number of epitopes belonging to Tri a 19, Tri a 20, Tri a 21, Tri a 26, Tri a 36 and ?-gliadins was observed in the Colosseo variety; whereas no significant epitopes degradation was observed for the Neolatino variety. These results proved that the combination of selected wheat variety with a customized microbiological detoxification treatment allowed the production of hypoallergenic prototype breads. However, the hydrolytic efficiency of the procedure is strongly genotype dependent.