The behaviour of the high molecular-weight glutenin subunit 1Dx5, the 58 kDa central repetitive domain and α-gliadins at the air–aqueous interface

• Published in: Journal of cereal science 2003, Vol.38 (2), p.147-156
• Main Authors: Örnebro, J., Nylander, T., Eliasson, A.-C., Shewry, P.R., Tatham, A.S., Gilbert, S.M.
• Format: Article
• Language: English
• Subjects: acetates; Biological and medical sciences; Cereal and baking product industries; Food industries; Fundamental and applied biological sciences. Psychology; gliadin; Gliadins; Glutenins; hydrophobic bonding; molecular weight; Repetitive domain; sodium chloride; Surface tension
• ISSN: 0733-5210; 1095-9963
• DOI: 10.1016/S0733-5210(03)00021-3

The surface pressure–molecular area ( Π– A) relationship for spread layers of the high molecular-weight glutenin subunit 1Dx5, a 58 kDa peptide derived from the central repetitive domain of the subunit, and an α-gliadin fraction was measured by means of a surface film balance (Langmuir trough). The aqueous phase was a 10 mM acetate buffer, pH 4.0, either with or without 100 mM NaCl. Subunit 1Dx5 generated much higher surface pressures than the 58 kDa peptide, whereas the α-gliadin fraction generally gave higher surface pressures than subunit 1Dx5. Furthermore, subunit 1Dx5, but not the 58 kDa peptide or the α-gliadin fraction, formed a highly cohesive film. The differences in the interfacial behaviour of subunit 1Dx5 and the 58 kDa peptide were ascribed to significant hydrophobic interactions for the subunit. The reversibility of a compression–expansion cycle was generally greater for the second cycle than for the first. For subunit 1Dx5 and the α-gliadins, but not the 58 kDa peptide, the reversibility was increased when NaCl was present in the aqueous phase.