Impact of Adding Polysaccharides on the Stability of Egg Yolk/Fish Oil Emulsions under Accelerated Shelf-Life Conditions.

Polysaccharides can form interfacial complexes with proteins to form emulsions with enhanced stability. We assessed the effect of adding gum guar or gum arabic to egg yolk/fish oil emulsions. The emulsions were produced using simple or high-pressure homogenization, stored for up to 10 days at 45 °C, and characterized for their particle size and distribution, viscosity, encapsulation efficiency, oxidative stability, and cytotoxicity. Emulsions containing gum guar and/or triglycerides had the highest viscosity. There was no significant difference in the encapsulation efficiency of emulsions regardless of the polysaccharide used. However, emulsions containing gum arabic displayed a bridging flocculation effect, resulting in less stability over time compared to those using gum guar. Emulsions produced using high-pressure homogenization displayed a narrower size distribution and higher stability. The formation of peroxides and propanal was lower in emulsions containing gum guar and was attributed to the surface oil. No significant toxicity toward Caco-2 cells was found from the emulsions over time. On the other hand, after 10 days of storage, nonencapsulated fish oil reduced the cell viability to about 80%. The results showed that gum guar can increase the particle stability of egg yolk/fish oil emulsions and decrease the oxidation rate of omega-3 fatty acids.

Effect of Phospholipase A1 and High-Pressure Homogenization on the Stability, Toxicity, and Permeability of Egg Yolk/Fish Oil Emulsions.

Enzymatic treatment of egg yolk with phospholipases can enhance its emulsifying properties and thermal stability. Additionally, a two-step process (primary and secondary homogenization) could form emulsions with better stability. Thus, in this study we used a split-split-plot in time design to assess the effect of enzymatic treatment, processing, and storage conditions on the encapsulation efficiency, stability, toxicity, and permeability of egg yolk/fish oil emulsions stored up to 10 days at 45 °C. Egg yolk solutions before and after treatment with phospholipase A1 were used as carriers of fish oil containing ≥82% eicosapentaenoic and docosahexaenoic acids. Emulsions were formed by primary (24,000 rpm, 4 min) and secondary (200 MPa) homogenization. The combined effect of treatment with phospholipase A1 and secondary homogenization resulted in emulsions with improved stability, increased the encapsulation efficiency of the carriers, and reduced the release of oil to the particle surface, resulting in lower formation of oxidation products. At the end of storage time, none of the emulsions were toxic to Caco-2 cells at a concentration of 75 µg/mL medium, while nonencapsulated fish oil reduced cell viability to 81%. Only eicosapentaenoic acid was detected in the basolateral side of Caco-2:HT29 monolayers, and its apparent permeability from nonencapsulated fish oil was significantly lower than that from emulsions.