Optimal functionality of iodate in industrial bread making - layered double hydroxides

Promovendus/a: Karl Lauwers

Promotor(en): Prof. dr. Christine Kirschhock, Prof. dr. ir. Jan Delcour, Dr. Eric Breynaert

Bread is a major component of our daily human diet. During mixing and fermentation, a continuous wheat gluten protein network is formed that results in a viscoelastic dough. The properties of this protein network highly depend on the wheat gluten protein composition and eventually determine volume and texture of the final baked product.
In industrial bread making, deficiencies and variations in flour quality have to be overcome to provide optimal and reliable end product quality. Redox agents such as potassium bromate or potassium iodate can be introduced into the bread making process to alter dough mixing properties, elasticity and extensibility, and to impact bread volume and bread crumb structure. The oxidizing effect of potassium bromate is optimal during bread making since it is especially active during later stages of fermentation and baking. However, there are serious potential health issues concerning bromate intake and carcinogenic hazard.
Potassium iodate poses no health concerns but is much more reactive than potassium bromate and will already be active at dough mixing stage. Due to its fast oxidizing activity, it negatively impacts dough extensibility and results in lower bread volume and bread crumb quality. Therefore, incorporation and encapsulation of iodate is developed in this thesis for the optimal controlled release of iodate. For the encapsulation and controlled release, layered double hydroxides (LDHs) will be used.
LDHs are lamellar structures that consist of positively charged cation-hydroxide layers and anions in the hydrated interlayer. Isomorphic substitution will determine type and composition of cation-hydroxide layer and consequently, anion exchange selectivity and –capacity of the LDH structure. LDHs increasingly gain interest for different types of applications due to its easy synthesis, morphological and structural tunability and good biocompatibility. LDH materials are already developed for diverse applications in catalysis, adsorption, or photo- and electrochemistry and are also promising materials for controlled release of pharmaceutical components.
In this thesis, a food-grade LDH materials is synthesized with good iodate selectivity for the controlled release of oxidant additives during fermentation and baking. The optimal controlled functionality of the iodate oxidizing effect in industrial bread making will therefore be a commercially relevant product for the bread making industry. The concept of encapsulation and controlled release of redox agents with inorganic (LDH) materials will be generalized in a schematic ‘flow chart’ to summarize opportunities for fine-tuning the encapsulation material and adjust controlled release characteristics to specific baking schemes or alternative redox agents.