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Enhancement of Protein Foam Stability by Formation of Wheat Arabinoxylan-Protein Crosslinks

¹Institute of Food Research, Norwich Laboratory, Norwich Research Park, Colney, Norwich NR4 7UA, England. ²Corresponding author. Fax: +44 1603 507 723. E-mail: peter.wilde@bbsrc.ac.uk ³Current address: DMV International, NCB-laan 80, PO Box 13, 5460 BA Veghel, The Netherlands.

The foam stability properties of a defined mixed solution of Tween 20 and bovine serum albumin was evaluated as a function of arabinoxylan concentration. A marked increase in the foam stability was observed with low concentrations of arabinoxylan. Maximum improvement in the foam stability was obtained with 0.2–0.3 mg/mL of arabinoxylan. Enhancement of foam stability due to a combination of bulk viscosity changes and surface effects was identified. The relative contribution of arabinoxylan to bulk viscosity and adsorbed layer structure was studied by examination of the properties of thin liquid films and the macroscopic air-water interface. Arabinoxylan reduced the rate of thin film drainage, increased the equilibrium thickness of the films, slowed the lateral diffusion of a fluorescent probe molecule located in the adsorbed layer, and increased the surface elasticity. These data are congruent with arabinoxylan-mediated crosslinking of adsorbed protein. These observations may be of significance in gas retention during breadmaking. In addition, this naturally occurring polysaccharide offers potential for use in the control of protein foam stability.