Impact of Galactolipids and Phosphatidylcholine on the Stability of Microalgal Oil‐In‐Water Emulsions

ABSTRACT Microalgal oil is a sustainable source of omega‐3 polyunsaturated fatty acids. However, it is very sensitive to lipid oxidation, especially in emulsions. While the presence of phospholipids and galactolipids in microalgal oil can influence its oxidation, their impact in oil‐in‐water emulsion is not yet fully understood. This study investigates the impact of phosphatidylcholine (PC), monogalactosyldiacylglycerol (MGDG), and digalactosyldiacylglycerol (DGDG) on the physical and oxidative stability of microalgal oil‐in‐water emulsions. Polar lipids were added at a concentration below (i.e., 25 μM) or above (i.e., 400 and 300 μM) their critical micelle concentration (CMC) in stripped and non‐stripped commercial microalgal oil, which were then emulsified with Tween 20. After homogenization, around 50% of DGDG, 70% PC, and 100% MGDG remained in oil droplets (i.e., including interface). All polar lipids increased the physical stability of the emulsions when added at concentrations above their CMC, with a stronger effect in stripped oil‐in‐water emulsions. Emulsions containing PC showed the highest physical stability due to its higher surface activity. Only the incorporation of 400 μM PC showed a slight antioxidant effect in stripped microalgal oil‐in‐water emulsions. These findings clarify the distinct roles of polar lipids in microalgal oil‐in‐water emulsions and highlight that their stabilizing function is primarily physical rather than oxidative.