## 3 Factors Influencing and Mechanistic Pathways in Egg Yolk Emulsification
### Chemical Treatment
#### 3.1.2 Egg yolk Complex Formation  
While the egg yolk emulsifying characteristics have been thoroughly investigated in basic, well-characterized model emulsion systems, in industrial processing, egg yolk-stabilized emulsions are subjected to a range of conditions and environmental stresses, including pH and ionic strength fluctuations, and various thermal, chilling, freezing, and drying treatments [55,56]. These emulsions can undergo a destabilization process like coalescence, flocculation, creaming, and Ostwald ripening, with flocculation being particularly difficult to manage. Flocculation is highly sensitive to multiple factors and can directly affect emulsion formation and other instability mechanisms, including coalescence and creaming [57]. Egg yolk protein-stabilized emulsions tend to destabilize after thermal processing or changes in pH and ionic strength (vide supra), which may limit their use as emulsifying agents. Therefore, in the food industry, polysaccharides, which are a significant category of biopolymers, are utilized as thickeners, emulsifiers, and gelling agents. Through electrostatic interactions, polysaccharides can decrease firmness and improve emulsification in food, thereby enhancing the structure of the original gel network [58,59]. Pectin, a widely used food additive, serves as an emulsifier in mayonnaise. It effectively stabilizes oil-in-water emulsions and works well in oil phases [60]. Proteins and polysaccharides often form complexes during food processing, which helps create stable and desirable food products. As a result, there is growing interest in improving the functionality of egg yolk proteins through conjugation with food-grade components. It is important to note, however, that while protein-polysaccharide complexes can stabilize emulsions, many are still affected by environmental factors such as pH and ionic strength [61]. Therefore, this subsection discusses recent studies investigating the role of these complexes in emulsification and emulsion stabilization. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline \multicolumn{4}{c}{**Non-thermal processing**} \\ \hline
**Technology** & **Processing parameters** & **Findings** & **Reference** \\ \hline Hyperbaric storage of egg yolk & 200 MPa for 28 days & Preserved emulsifying properties and prevented oxidation & [49] \\ \hline High-intensity ultrasound treatment on egg yolk & Power: 75, 150, 225, and 300 W for 10 min (ultrasound 3 s) & No significant difference in EAI at different power and maximum ESI at 150 W & [50] \\ \hline High-intensity ultrasound treatment on egg yolk & Power: 90, 180, 270, and 360 W for 10 min (ultrasound 3 s) & Maximum EAI at 270 W and no significant effect of power on ESI & [51] \\ \hline High-intensity ultrasound treatment on egg yolk & Power: 75, 150, and 210 W for 3 s, stop & Optimum processing conditions for maximum emulsifying stability was 210 W for 9 min at 30 \({}^{\circ}\)C & [52] \\ \hline High-intensity ultrasound treatment on LDL & 200 W for 10 min (ultrasound for 3 s, stop for 3 s) & LDL molecules underwent partial rearrangement/recombination, and their molecular interface became flexible and stretched, which enhanced the zeta-potential and surface hydrophobicity and thus slightly improved the solubility and emulsifying & [53] \\ \hline Ozonation of egg yolk & Ozone generation rate of 1 g/h and sample treatment times 0, 10, 20, 30, and 40 min & Maximum emulsifying properties at 20 min treatment & [54] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Cont. [PERSON] et al. [38] investigated the use of an egg yolk-modified starch complex as a novel emulsifier for stabilizing HIPFs. They used octenyl succinic anhydride (OSA) to represent surface-active polysaccharides and hydroxypropyl distarch phosphate (HPDSP) to represent non-surface-active polysaccharides. The study observed that adding modified starch decreased the particle size of the emulsion by strengthening the electrostatic repulsion between egg yolk protein aggregates.