Title project: Influence of protein conjugation and interfacial structure on the stability of food emulsions
Many foods we consume in our daily life are oil-in-water (O/W) emulsions, such as milk, mayonnaise, and salad dressings, where oil droplets are dispersed in an aqueous phase. Emulsions can be subjected to destabilization in a number of ways. First, physical destabilization (e.g., coalescence) leads to appearance defects and the eventual physical destruction of the systems. Second, when the oil phase contains unsaturated lipids, the latter can oxidize, which damages the emulsion’s sensory and nutritional quality. The interfacial layer between the oil and water phases is known to largely influence the physical and chemical stability of food emulsions. Thus, it is important to understand how different emulsifiers influence the properties of the oil-water interfaces, and which types of emulsifiers are effective stabilizers. Generally, low molecular weight surfactants or amphiphilic biopolymers are used to stabilize emulsions by generating electrostatic and/or steric repulsion. However, stabilization of emulsions can also be achieved by colloidal particles that accumulate and strongly adsorb at the oil-water interface. Such particle-stabilized emulsions (i.e., Pickering emulsions) have been proved to be remarkably stable against coalescence as well as Ostwald ripening, but information about the influence of Pickering particles on lipid oxidation is currently limited. We aim to investigate how food compatible emulsions can be used to prevent lipid oxidation in emulsions, via physical and/or chemical barrier effects.
- To develop protein-polysaccharide microgel particles as Pickering stabilizers in O/W emulsions.
- To study how systematic variations of the molecular composition or physical structure of emulsifiers influence the physical and chemical stability of emulsions.
- To use these outcomes to improve the oxidative stability of O/W emulsions.
- Protein-polysaccharide microgels prepared via Maillard reaction and self-assembly approach will be used to formulate Pickering emulsions.
- O/W emulsions stabilized by different emulsifiers (i.e., proteins, protein-polysaccharide conjugates and protein-polysaccharide microgels) and protein-stabilized emulsion-filled hydrogels will be prepared and their physical properties will be characterized.
- Markers of lipid oxidation in emulsions such as hydroperoxides, total aldehydes, and volatile compounds will be measured during emulsion storage.
- Antioxidants may be incorporated into the particles to improve the chemical stability of emulsions.