The effect of mixing and wheat protein/gluten on the gelatinization of wheat starch

Protein was extracted with 0.1 M acetic acid and gluten was isolated from durum and Hard Red Spring (HRS) wheat. The extracted and isolated proteins were used to investigate their effect on the gelatinization of starch using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Starch and protein in different ratios were mixed with water using a spatula in test tubes and tested in a Brabender Farinograph. The data showed that mixing was an important factor, affecting starch DSC gelatinization parameters, TGA profile path and final weight loss of the blends. The starch onset and peak temperatures and ΔH of the mixed blend were compared with the unmixed blend. Mixing increased the onset and the peak temperatures of the starch gelatinization and decreased the ΔH. Higher amounts of protein in the blend increased the onset and peak temperatures and decreased the ΔH of the starch gelatinization. Protein extract and gluten were found to interact differently with starch and influence its gelatinization parameters and water evaporation, as measured by DSC and TGA, respectively.