Potential biological fate of emulsion-based delivery systems: lipid particles nanolaminated with lactoferrin and β-lactoglobulin coatings.

Purpose: To develop lipid particles coated by nanolaminated protein coatings as potential oral delivery systems to encapsulate, protect, and deliver lipophilic bioactives.

Methods: Nanolaminated protein coatings were formed by sequential electrostatic deposition of cationic lactoferrin (LF) and anionic β-lactoglobulin (BLG) at pH 6.5: LF, LF-BLG, LF-BLG-LF, and LF-BLG-LF-BLG. Changes in physicochemical properties were characterized after exposure to environmental stresses (pH 2 to 9; 0 to 200 mM NaCl) and simulated gastrointestinal tract (GIT) conditions (mouth, stomach, small intestine). Triglyceride digestion and β-carotene bioaccessibility were also measured.

Results: The pH and salt dependence of the electrical charge and aggregation stability of the emulsions were strongly influence by the structure of the interfacial coatings. All emulsions behaved similarly under simulated GIT conditions: extensive droplet aggregation occurred in the stomach and small intestine; triglycerides were rapidly and fully digested after exposure to intestinal fluids; the bioaccessibility of β-carotene was low (< 4%).

Conclusions: Nanolaminated protein coatings may be useful for stabilizing encapsulated lipids in functional food and pharmaceutical products during storage, but releasing them after ingestion. Protein coatings had little impact on triglyceride digestion, but they greatly reduced β-carotene bioaccessibility, possibly due to binding to lactoferrin.