Molecular information for addressing climate changes (and consumers’ demands): wheat proteins

Climate change and shifting patterns in the consumer’s demand represent major challenges for the agrifood chain. In the case of grain-based products, consumers would appreciate staple foods (pasta and bread) with traditional sensory features but without their nutritional drawbacks, such as the high glycemic index. Protein networks play a crucial role in defining the sensory characteristics in cereal-based products by forming both covalent and non-covalent interactions. Process-induced structural changes (and their kinetics) affect the organization of proteins in the network, resulting in macroscopic changes. However, other components in the matrix may affect a number of steps in the process, including competition for water at various steps of processing. A detailed knowledge of these effects is also pertinent to the production of food enriched with nutritionally relevant ingredients - including fiber, phenolics, and other bioactives - obtained from agrifood by-products. This work addresses the pattern of protein-protein interactions in isogenic bread wheat lines, that included a control line (WT), a waxy (i.e. no amylose) line (WX), and a high-amylose line (HA), along with a commercial bread wheat flour. Protein profiles were assessed by mono- and bi-dimensional electrophoresis. The chemical nature of protein-protein interactions was assessed by studying the sensitivity of the water-insoluble proteins to the sequential addition of salts, chaotropes, and disulfide reductants. Properties of hydrophobic patches on the protein surface were assessed by measuring binding of ANS (1,8 aniline naphthalene sulfonate) by front-face fluorescence. A “thiolomics” approach based on labeling of thiols with 5-(iodoacetamide) fluorescein (IAF) was used to assess the accessibility of protein thiols in the original materials and in protein fractions solubilized in suitable solvent systems. The protein patterns in the isogenic wheats were identical, but different from that in the commercial flour in both gluten components (monomeric gliadins and polymeric glutenins). In spite of the identical protein profile, the sensibility of the insoluble protein aggregates to both chaotropes and disulfide reductants in the isogenic samples increased in the order: WT<