An investigation on gluten aggregation properties using a high shear-based technique
This thesis is an investigation on gluten aggregation properties using a high shear-based technique. The Gluten Peak Tester (GPT) has the ability to differentiate between gluten aggregation time and gluten strength of flours of different cultivars. Differences in gluten aggregation are also observed when the gluten-forming environment is altered. Gluten aggregation was studied by the addition of salts of the Hofmeister series, aqueous alcohol, dilute acid, or pH changes. Gliadin and glutenin fractions from wheats of varying protein quality were also isolated and interchanged to observe effects on gluten aggregation time and strength. The chaotropic or kosmotropic nature of the salts dictated gluten aggregation, while alcohol, acid, and pH changes altered gluten aggregation due to their effect on solubility and conformation. Varying gliadin to glutenin ratio had a strong effect on gluten aggregation properties, while interchanging protein fractions between flours resulted in aggregation times and strengths intermediate to the flours. The study showed that electrostatic, hydrophobic, and hydrogen bond interactions play a role in gluten aggregation and that cultivar-specific differences in protein fractions also dictate gluten quality. The important role of water in gluten formation was also highlighted. In addition, the GPT was demonstrated to be an appropriate technique for studying gluten aggregation properties.