Controlling the potential gastrointestinal fate of β-carotene emulsions using interfacial engineering: Impact of coating lipid droplets with polyphenol-protein-carbohydrate conjugate

- β-Carotene emulsions were stabilized by chlorogenic acid-lactoferrin-polydextrose conjugate.
- Ternary conjugate increased the aggregation stability of β-carotene emulsions during digestion.
- Ternary conjugate had little impact on lipid digestion, but increased β-carotene bioaccessibility.
- The importance of including the oral phase in simulated gastrointestinal models was highlighted.

The impact of interfacial coatings comprised of polyphenol-protein-carbohydrate conjugates on the properties of nutraceutical-fortified lipid droplets during digestion was investigated. Surface-active chlorogenic acid-lactoferrin-polydextrose (CA-LF-PD) conjugate was synthesized as emulsifier to stabilize lipid droplets in β-carotene-enriched oil-in-water emulsions. Changes in droplet size, charge, and microstructure were monitored as β-carotene emulsions were passed through a simulated gastrointestinal tract model (mouth, stomach, small intestine). LF-coated droplets were unstable to flocculation at pH 8.0-9.0, due to the reduction in electrostatic repulsion, but CA-LF-PD conjugate-coated droplets were stable. Emulsions stabilized by ternary conjugate had better stability to droplet aggregation under simulated GIT conditions than other systems, which increased β-carotene bioaccessibility. The importance of including an oral phase in the simulated GIT model was also demonstrated. The ternary conjugate-stabilized emulsions developed in this study have potential applications as protectors and carriers of hydrophobic drugs, supplements and nutraceuticals.