Influence of emulsifier type on the in vitro digestion of fish oil-in-water emulsions in the presence of an anionic marine polysaccharide (fucoidan): Caseinate, whey protein, lecithin, or Tween 80

Abstract

The influence of an anionic marine polysaccharide (fucoidan) on the gastrointestinal fate of emulsified fish oils stabilized by different types of natural and synthetic emulsifier was examined: whey protein isolate (WPI); caseinate; lecithin; Tween 80. Oil-in-water emulsions in the absence and presence of fucoidan were passed through a simulated gastrointestinal tract (GIT) that included mouth, stomach, and small intestine phases. The change in droplet properties (particle size, charge, and organization) was measured throughout the GIT and the rate and extent of lipid digestion was measured in the small intestine phase. The presence of fucoidan increased the initial digestion rate of caseinate- and WPI-stabilized emulsions due to its ability to modulate lipid droplet aggregation. The fucoidan appeared to suppress isoelectric aggregation of the droplets, which increased the surface area of lipids available for the lipase molecules. On the other hand, the presence of fucoidan had little impact on the digestion of emulsions stabilized by lecithin or Tween 80, since it did not strongly impact the lipid droplet aggregation state. These results have important implications for the fabrication of functional foods and beverages that can control lipid digestion in the gastrointestinal tract.