Proteins and polysaccharides are commonly used in assembling biopolymer-based delivery systems. The purpose of this research was to investigate the effect of sodium chloride on the physical and creaming stability of whey protein isolate (WPI) stabilized fish oil-in-water (O/W) emulsions containing xanthan (XG)-locust bean gum (LBG) mixtures. The O/W emulsions containing 0.2% XG-LBG mixtures were compared to emulsions with 0.2% XG and 0.2% LBG separately, and control with no polysaccharides. The stability of the emulsions was assessed by measuring droplet particle size, creaming index, viscosity, and microstructure. Emulsions were also measured within 24 hours of being made and then again after 2 weeks to study the effect of storage. Results indicated that salt concentration had no significant effect on the particle size of the oil droplets, suggesting that the interaction between WPI and XG-LBG was weak at neutral pH. At 0 mM and 5 mM NaCl, XG-LBG emulsions had the highest creaming stability by demonstrating the greatest resistance to phase separation. At 50 mM XG emulsions had the highest creaming stability, because as the addition of salt increases, the synergistic interaction that occurs between xanthan gum and locust bean gum is decreased due to electrostatic screening. The viscosity of all emulsions decreased as the salt concentrations, as well as storage time increased. At all salt concentrations and over time XG-LBG emulsions had the highest viscosity, with 0 mM NaCl emulsions having the best. The addition of NaCl causes the droplet to become more compact, reducing the viscosity. Microstructure results indicated that flocculation is lower in both XG-LBG and XG emulsions compared to the highly flocculated LBG and WPI emulsions. These results have important implications in development of biopolymer-based emulsion delivery systems.

Influence of salt on the stability of oil-in-water emulsions containing whey protein-xanthan-locust bean complexes

253rd National Meeting (2017)

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