Properties Of Gliadin Research Articles

Gliadin interacted with tea polyphenols: potential application and action mechanism

The effect of tea polyphenols (TPs) on noodles quality was investigated, and the interaction mechanism between catechins and gliadins was explored. With TPs addition, noodles showed the significant changes in physicochemical and sensory properties. The water absorption, tensile strength and elasticity increased by 1.35%, 4.98%, 28.51% with 0.5% of TPs, and then decreased with the increasing of TPs. According to the determinations of surface hydrophobicity, spatial structure, thermal properties, amidogen and sulfhydryl content, the structure and properties of gliadin were affected by catechins. Esterified catechins tended to disrupt gliadin structures and non-esterified catechins polymerised gliadin molecules. Furthermore, molecular docking results indicated that catechins interacted with gliadin mainly by hydrogen bonds and hydrophobic action. The reactivity of catechins with gliadin was in the sequence as: epigallocatechin gallate > epicatechin gallate > epigallocatechin > epicatechin, which was based on the account of gallate and B-ring hydroxyl number discrepancy. All results suggested that catechins affected greatly on gliadin, and TPs were potentially used to improve the quality of flour products.

Structural Study of Wheat Gliadin in Different Solvents by Spectroscopic Techniques

Physicochemical properties of gliadin in different solvents (dimethyl sulfoxide (DMSO), H2O, and aqueous ethanol) and pH (9.8, 6.8, and 1.2) were investigated using dynamic light scattering (DLS), zeta potential (ZP), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Gliadin-DMSO and gliadin-deionized water (H2O) (pH 9.8) showed a lower size distribution, whereas samples solubilized in 60% aqueous ethanol presented a lower size distribution only at pH 1.2. ZP analysis showed that gliadin-H2O (pH 9.8) was the most stable evaluated system. ZP results of gliadin-DMSO indicated an unstable system, with the coexistence of several protein conformations. ATR-FTIR analysis showed that, in H2O, most protein conformations were β-sheets, while in DMSO a band at 1660 cm−1 appeared to be related to protein unfolding. The techniques proved to be effective in monitoring conformation and stability of all gliadin/solvent systems. Such information can be used in the development of new gliadin-based materials.

Inhibition of epithelial growth factor receptor signalling does not preserve epithelial barrier function after in vitro gliadin insult

Objective. In coeliac disease, small-bowel mucosal permeability is increased in response to gluten consumption. However, the signalling routes leading to such a barrier defect remain obscure. As the epidermal growth factor receptor (EGFR) pathway is up-regulated in untreated coeliac disease, and since this cascade has been related to epithelial hyperpermeability, the aim of this study was to establish whether blocking the EGFR route would restore the barrier after gliadin insult in vitro. Material and methods. Epithelial barrier function was assessed by measuring transepithelial electrical resistance (TER) in Caco-2 epithelial monolayers treated with pepsin trypsin (PT)-digested gliadin with or without monoclonal antibodies against EGFR family members or by inhibitors of the EGFR pathway signalling molecules. Furthermore, tight-junctional integrity was determined by Western blotting and immunofluorescence staining of the tight-junctional protein occludin. Results. PT-gliadin significantly reduced TER and the expression of occludin protein. Blocking of the EGFR signalling pathway could not prevent gliadin-triggered damage. In fact, a function-blocking monoclonal antibody against EGFR (ErbB1) actually potentiated the harmful effects of gliadin on TER. Conclusions. The epithelial barrier-disrupting properties of gliadin are independent of the EGFR signalling cascade. However, our results suggest that activation of the EGFR pathway might actually be protective against gliadin-triggered hyperpermeability. Further studies are needed to elucidate the specific gliadin-triggered signalling cascades which lead to increased epithelial permeability in coeliac disease.