The effects of different types of polysaccharides on the structure and physical properties of W/O/W emulsions under varying pH conditions.

BACKGROUND

Biopolymer based water-in-oil-in-water double (W/O/W) emulsion systems comprise a complex emulsion system that might be affected by several factors and the status at multiple phases. The present study investigated the physicochemical properties of W/O/W double emulsions with inner W phase incorporated with various polysaccharides and the outer phase stabilized by whey protein isolate (WPI). Six different polysaccharides were selected as co-emulsifiers in the inner phase, and their effects on morphology, droplet size, zeta potential and rheology properties were evaluated. Furthermore, the impact of WPI/polysaccharide concentration and pH on the physicochemical properties and storage stability of the emulsions was compared.

RESULTS

Emulsions with an inner phase incorporated with xanthan gum and carrageenan exhibited better stability than others. Increasing the concentration of WPI enhanced the overall stability of the double emulsion, although it compromised the integrity of the internal W/O interface. On the other hand, a 1.0% concentration of polysaccharide, specifically when carrageenan is used, slowed down droplet floating and coagulation. An acidic external aqueous phase (pH 4) led to larger and more uniform particle size distributions, as well as enhanced stability. The lower pH decreased the viscosity and delayed molecular exchange in the oil phase, thereby preserving the structure of the double emulsion.

CONCLUSION

These findings contribute to a better understanding of the factors influencing the stability and properties of W/O/W double emulsions with addition of anionic polysaccharides in the inner water phase. © 2024 Society of Chemical Industry.