Functional modification of vital wheat gluten with corn syrup using hydrothermal treatment

Abstract

AbstractFunctional properties of gluten modified using hydrothermal treatment were compared with those of vital wheat gluten (VWG). Gluten slurry was jet cooked under pressure in the presence of corn syrup (CS) at different temperatures (121 and 149 °C) for different times and then spray dried. Foaming properties for all samples (treated and untreated) at different pHs showed that, although the optimum pH was 5, at this pH the treated gluten samples displayed reduced foaming properties as compared with the control, whereas at all other pHs there was an increase in foaming properties. The sample treated with CS at 121 °C (JC121w/cs) showed the highest viscosity and elasticity increase among all treated samples. Emulsifying properties were adversely affected by an increase in temperature of treatment, whilst addition of CS helped to restore emulsion stability (ES). The sample VWG with CS (Cont.w/cs) at pH 3 showed maximum ES. In general, samples after treatment showed increased solubility. The hydrophilic but non‐ionisable sugar hydroxyl groups affected the functionality at lower pH. Molecular changes were followed by size exclusion high‐performance liquid chromatography (SE‐HPLC) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). Samples subjected to the lower temperature (121 °C) showed a shift of the molecular weight distribution to higher values in the HPLC profile, consistent with higher viscosities for this treatment. For the same samples, SDS‐PAGE of the reduced protein exhibited a decrease in the intensity of bands corresponding to high‐molecular‐weight glutenin subunits, complementing the fact that large‐molecular‐size polymers are involved during protein modification. Copyright © 2005 Society of Chemical Industry