Understanding high pressure-induced changes in wheat flour–water suspensions using starch–gluten mixtures as model systems

The effect of high pressure (HP) on wheat flour–water suspensions was investigated. Suspensions were treated for 10 min at 200–600 MPa. HP-treatment significantly increased the consistency of the flour suspensions, as studied by frequency sweep tests. Temperature sweeps revealed that HP-induced starch gelatinisation, with a sigmoidal-shaped correlation between degree of gelatinisation and treatment pressure. Analysis of protein solubility in different buffers indicated the HP-induced formation of urea-insoluble complexes and/or disulphide bonds. Furthermore, the effects of HP on the isolated components wheat starch and gluten were studied, and starch–gluten mixtures were used as a model system for flour. A negative effect of gluten on the consistency increase of starch suspension was observed. Comparing the rheological parameters of HP-treated wheat flour suspensions to those of starch suspensions, confirmed the weakening effect of gluten. However, the presence of gluten in flour could not fully explain the differences between starch and flour suspension.