In-vitro digestion of whey protein- and soy lecithin-stabilized High Oleic Palm Oil emulsions

Sweet whey- and soy lecithin-stabilized emulsions have been studied as potential delivery systems of High Oleic Palm Oil bioactive compounds. However, the gastrointestinal behavior of these systems has not been investigated. In this work, two High Oleic Palm Oil emulsions were submitted to in vitro digestion using a standardized static method. Stability of the emulsions was followed in each digestive phase and the final extent and kinetics release as well as the bioaccessibility of free fatty acids were measured and compared against non-encapsulated control. No changes were found in the droplet size of the emulsion after oral digestion, however, during gastric digestion, destabilization was observed due to the pH and the ionic strength of the medium. During the intestinal phase, nanoemulsions showed the highest rate constant followed and the least free fatty acids release final extent (78.48 ± 3.08 wt%) in comparison with macroemulsions (86.06 ± 2.04 wt%) and control (107.77 ± 1.45 wt%). Saturated fatty acids showed lower bioaccessibility in both emulsions than for control, meanwhile it increased for unsaturated ones. The results obtained allow addressing future research in formulation and design of delivery systems to improve the High Oleic Palm Oil digestibility and bioactive compounds bioaccessibility.