Many foods are emulsions, such as pesto and mayonnaise. Emulsions are biphasic systems of two immiscible liquids dispersed into each other as small droplets. Therefore, these systems contain a high amount of free energy and tend to destabilize to reduce the amount of oil-water interface. To prevent destabilization, an emulsifying agent (e.g., surfactant, proteins, polysaccharides, colloidal particle) is generally added to the system. Dairy proteins are known to form interconnected, strong interfacial films within hours, but the phenomena at the short timescales relevant to emulsification are poorly understood. Furthermore, from a sustainability point of view, the choice of plant-based alternatives (such as pea, faba bean and potato proteins) is preferred, and is even to some extent demanded from a consumer perspective. However, the current knowledge base for technical functionality of plant-based proteins is limited leading to challenges for emulsification.
The focus of this project is products with a pH around the isoelectric point of many proteins (pH 4-5), and often destabilizes after thermal treatment. In order to understand instability of such food emulsions, we will systematically investigate the effect of pH and temperature on the interfacial properties and stability of emulsions. For this, a combination of conventional model emulsions and microfluidic techniques will be used. The main research contents are as follows:
1. The role of pH on the interfacial properties and emulsion stability.
2. Interfacial properties at different temperatures (20-95?).
3. Interfacial properties and stability of protein emulsions in the presence of polysaccharide.
4. Early film formation in protein-stabilized emulsions within short time scale (i.e., in milliseconds).