Egg yolk: structures, functionalities and processes

Area of Science:

• Food science and technology
• Biophysical chemistry
• Materials science

Background:

• Egg yolk comprises natural supramolecular assemblies of lipids and proteins.
• These assemblies are crucial for yolk's emulsifying properties, particularly in food production.
• Interactions between yolk proteins and phospholipids drive these structures.

Purpose of the Study:

• To review the multi-scale structures within hen egg yolk.
• To explore how processing treatments modulate these structures and emulsifying properties.
• To understand the role of plasma and granule fractions in yolk's functionality.

Main Methods:

• Literature review focusing on supramolecular assemblies in egg yolk.
• Analysis of structural changes induced by thermo-mechanical and high-pressure treatments.
• Examination of the relationship between structure, processing, and emulsifying capabilities.

Main Results:

• Egg yolk consists of plasma (lipoprotein-rich) and granule (protein-rich) fractions with distinct structures and properties.
• Plasma exhibits significant emulsifying properties, while granules offer functionality when forming micelles.
• External treatments like high pressure and heat alter yolk's structural organization and functionalities.

Conclusions:

• Understanding yolk's supramolecular organization is key to controlling its emulsifying properties in food systems.
• Processing treatments can modify yolk structures, offering avenues for commercial exploitation of its fractions.
• The distinct behaviors of plasma and granule fractions under stress are critical for targeted applications.