Abstract
Oil in water emulsions are commonly stabilized by emulsifying constituents like proteins and/or low molecular weight emulsifiers. The emulsifying constituents can compete or coexist at the interface. Interfacial properties thus depend on molecular structure of the emulsifying constituents and the oil phase and the resulting molecular interactions. The present study systematically analyzed the impact of fatty acid saturation of triacylglycerides and phosphatidylcholine on the interfacial properties of a β-lactoglobulin-stabilized interface. The long-term adsorption behaviour and the viscoelasticity of β-lactoglobulin-films were analyzed with or without addition of phosphatidylcholine via drop tensiometry and dilatational rheology. Results from the present study showed that increasing similarity in fatty acid saturation and thus interaction of phosphatidylcholine and oil phase increased the interfacial tension for the phosphatidylcholine alone or in combination with β-lactoglobulin. The characteristics and stability of interfacial films with β-lactoglobulin-phosphatidylcholine are further affected by interfacial adsorption during changes in interfacial area and crystallization events of low molecular weight emulsifiers. This knowledge gives guidance for improving physical stability of protein-based emulsions in foods and related areas.Graphic abstract
Highlights
Oil in water emulsions are common systems in the food or pharmaceutical industry
A β-lactoglobulin droplet was formed in Medium chain triglyceride oil (MCT-oil) or sunflower-oil-phosphatidylcholine mixtures
The present study analyzed the impact of interactions and solubility of oil phase and low molecular weight emulsifiers depending on saturation of fatty acids on the interfacial properties of β-lactoglobulin as model protein
Summary
Oil in water emulsions are common systems in the food or pharmaceutical industry. The immiscible phases are stabilized with emulsifying constituents namely proteins and/or low molecular weight emulsifiers. In a wide range of applications, proteins and low molecular weight emulsifiers are actively used in combination or co-occur through their presence in specific food ingredients. Proteins can be displaced by highly interfacial active low molecular weight emulsifiers [1, 10] or both can coexist. Coexistence can result in interactions via hydrogen bonding, hydrophobic or electrostatic effects [7, 11, 12]. Electrostatic effects depend on the isoelectric point of the proteins [2], the pka value for low molecular weight emulsifiers [13] and the characteristics of the aqueous phase like pH or ionic strength [2]. The multitude of interactions between emulsifying constituents determines the characteristics and viscoelasticity of interfacial films and emulsion stability. A film with high viscoelasticity results from attractive interactions [9]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call