Emulsion Properties and Functional Characteristics of Egg Yolk Systems

Egg yolk systems serve as key food emulsifiers due to a complex composition of proteins, lipids and phosphoproteins dispersed as plasma and granules. The interplay between low-density lipoproteins (LDLs), high-density lipoproteins (HDLs), phosvitin and granule structures governs emulsion formation, stability and rheology. Upon thermal or mechanical treatment, yolk proteins undergo denaturation, aggregation and gelation, modulating viscosity, droplet size and network microstructure. Egg yolk lecithins and phospholipids contribute to interfacial activity, while granule complexes can stabilise Pickering emulsions with high internal phase fractions. Functional characteristics include foaming, gelation, water and oil binding capacities, and antioxidant properties. These attributes underpin applications in sauces, dressings, baked goods and novel fat replacements. Recent advances have interrogated non-equilibrium dynamics, structural modifications under pressure and ionic conditions, and innovations in extraction and fractionation techniques. Together, these findings highlight the versatility of yolk-derived ingredients and the potential for tailored functionality in food and biomedical formulations.

Research from Nature Portfolio

Recent studies have explored the microscopic dynamics and non-equilibrium transformations of egg yolk under heat. Using coherent X-ray photon correlation spectroscopy, researchers have delineated how protein denaturation and aggregation control viscosity, while LDL clustering dictates the development of a grainy-gel network. The work revealed Arrhenius-type time-temperature superposition for both protein gelation and LDL aggregation up to a threshold temperature, above which gelation dynamics decouple from thermal acceleration. These insights clarify the mechanistic basis for yolk texture formation and offer quantitative frameworks for predicting behaviour during cooking and processing.

Emulsion Properties and Functional Characteristics of Egg Yolk Systems publication trend

The graph below shows the total number of articles in emulsion properties and functional characteristics of egg yolk systems across all publications each year (not limited to Nature Index journals).

Technical terms

Low-density lipoproteins (LDLs): Spherical lipid–protein complexes in yolk plasma critical for controlling droplet aggregation and microstructure.

Yolk granules: Aggregates of proteins and lipids forming natural particles capable of stabilising Pickering emulsions.

Time-temperature superposition (TTS): A principle whereby temperature shifts can be used to predict time-dependent reaction kinetics over a range of conditions.

High internal phase emulsion (HIPE): Emulsions with an internal phase volume fraction exceeding 74 %, producing gel-like textures.

Ultra-high pressure homogenization (UHPH): A mechanical process applying pressures above 100 MPa to modify protein structures and functional properties.

References

1. Exploring non-equilibrium processes and spatio-temporal scaling laws in heated egg yolk using coherent X-rays. Nature Communications (2023).
2. Perspectives on lecithin from egg yolk: Extraction, physicochemical properties, modification, and applications. Frontiers in Nutrition (2023).
3. Formation of Natural Egg Yolk Granule Stabilized Pickering High Internal Phase Emulsions by Means of NaCl Ionic Strength and pH Change. Foods (2022).
4. Effect of ultra-high pressure homogenization on structural and techno-functional properties of egg yolk granule proteins. LWT (2023).
5. Thermal Processing of Liquid Egg Yolks Modulates Physio-Chemical Properties of Mayonnaise. Foods (2022).