## 3 Factors Influencing and Mechanistic Pathways in Egg Yolk Emulsification
### Chemical Treatment
#### 3.1.2 Egg yolk Complex Formation
Egg Yolk Plasma-Pectin/Guar Gum Complex  
Enulsions containing 1% egg yolk plasma exhibited rapid creaming, reaching approximately 50% within the first hour, followed by a slower rate, culminating in 61% creaming after 10 h. The addition of low pectin concentrations (0.01% and 0.1% \(w/v\)) slightly decreased creaming, while higher concentrations progressively decreased creaming, completely preventing it at 0.5% \(w/v\). Guar gum exhibited a more pronounced anti-creaming effect compared to pectin. At 0.05% and 0.2% \(w/v\) guar gum, creaming reduced to 57% and 39%, respectively, after 10 h. Complete creaming prevention was achieved at 0.5% \(w/v\). This enhanced stability was assigned to the higher viscosity of the continuous phase imparted by guar gum [40]. At low hydrocolloid concentrations (0.01-0.05% \(w/v\)), the emulsion exhibited a diffuse interface between the cream and serum phases, with a turbid serum indicating the presence of oil droplets. This is a feature of polydisperse emulsions with minimal hydrocolloid stabilization. Conversely, at higher hydrocolloid concentrations (0.1-0.5% \(w/v\)), a distinct interface and clear serum phase were observed, indicative of complete emulsion flocculation [40]. Egg Yolk Granule-Soybean Lecithin Complex  
Without lecithin, emulsions stabilized by native granules (at pH 7) and disrupted granules (at pH 9) began creaming after 1 and 3 days of storage, respectively. Emulsions stabilized by disrupted granules exhibited a significantly lower creaming index (\(p<0.05\)) than those stabilized by native granules at the same lecithin concentration. Both native and disrupted egg yolk granules demonstrated an initial increase followed by a decline in  
Figure 5: Schematic diagram of egg yolk and different phase behavior egg yolk–carboxymethyl cellulose complex stabilized emulsions. Reprinted with permission from [PERSON] et al. [37]. 2024, Elsevier. emulsifying stability as lecithin levels rose. The best emulsifying stability was observed in emulsions containing 0.25% lecithin. A notable finding was the absence of a droplet-free phase at the bottom of the emulsion made with disrupted granules and 0.25% lecithin after 7 days of storage. This indicated that granule dissociation, facilitated by a suitable amount of lecithin, can enhance emulsifying stability, although excessive lecithin may impede emulsifying activity due to competitive adsorption between egg yolk granules and lecithin at the interface. It was also evident that emulsions with 1% lecithin did not achieve the expected cream stability, indicating that lecithin alone is insufficient to stabilize oil droplets [36]. Egg Yolk HDL-Phosvitin Proteins Complex  
A recent study by [PERSON] et al. [39] explored the potential of egg yolk HDL and phosvitin as stabilizers for HIPEs. In optimal circumstances (pH 3, 2% ionic strength, 2% HDL), HDL by itself may stabilize HIPEs. The addition of phosvitin to HDL resulted in smaller particle sizes and reduced surface tension, with the optimal ratio being 1:1 HDL to phosvitin. HDL-phosvitin mixtures stabilized HIPEs with average particle sizes of around 15 um at pH 3. Incorporating calcium ions (0.2 M Ca\({}^{2+}\)) further enhanced stability, reducing particle size to approximately 10.86 um. These findings demonstrated the ability of HDL, phosvitin, and calcium ions in improving the emulsifying properties to produce highly stable HIPEs at a low pH. The stabilization mechanism of HIPEs by the egg yolk HDL-phosvitin protein complex involved several key factors. Firstly, the pH level had a significant impact on protein aggregation. Proteins aggregated as huge polymers at the oil-water interface, causing their correct alignment to be disrupted when the pH approached their isoelectric threshold. Consequently, HDL was unable to efficiently combine to form stable electrostatic complexes with phosvitin, which caused the emulsion droplets to enlarge at pH values of 6 or 5.