Controlling lipid digestibility: Response of lipid droplets coated by β-lactoglobulin-dextran Maillard conjugates to simulated gastrointestinal conditions

There is considerable interest in controlling the digestibility of lipids within the human gastrointestinal tract. In this study, we examined the influence of coating lipid droplets with β-lactoglobulin-dextran Maillard conjugates on their physicochemical stability and lipase digestibility under simulated gastrointestinal conditions. Initially, Maillard conjugates were prepared by dry-heating freeze-dried β-lactoglobulin and dextran under controlled conditions (76% relative humidity, 60 °C, 24 h). Particle size and charge measurements showed that conjugation of β-lactoglobulin with dextran altered lipid droplet responsiveness to pH (7.0–3.0), gastric pepsin (0–2 h), ionic strength (0–60 mM CaCl2), bile (0–25 mg/mL), and pancreatic lipase. Increasing the molecular weight of the dextran moieties attached to the β-lactoglobulin molecules increased emulsion stability and slightly decreased lipid digestibility, which was attributed to an increase in steric repulsion. This research should facilitate the rational design of Maillard conjugates to improve emulsion stability, control lipid digestion, and deliver lipophilic bioactive components within the gastrointestinal tract.