Emulsification and oxidation stabilities of DAG‐rich algae oil‐in‐water emulsions prepared with the selected emulsifiers

BACKGROUND Diacylglycerol (DAG) reduces body weight, suppresses body fat accumulation, and lowers the blood lipid concentration, and docosahexaenoic acid (DHA) can reduce the risk of occurrence of coronary artery diseases. RESULTS DAG‐rich algae oil with a high DHA content (55.9%) was synthesized via the lipase‐catalyzed glycerolysis of algae oil, which consisted of triacylglycerol (43.9 mol%), DAG (40.9 mol%), and monoacylglycerol (15.2 mol%). The DAG‐rich algae oil‐in‐water emulsions were prepared using three emulsifiers [whey protein concentrate (WPC), Tween80, and Tween80 + Span80]. The WPC‐emulsion formed a thicker serum layer (6.67% at day 51) and larger oil droplets ( d 32 , 0.37 μm at day 28) than the Tween80‐ and Tween80 + Span80‐emulsions (3.33–4.17%; 0.26 μm), and an upper cream layer with excess oil droplets was observed in only the WPC‐emulsion, indicating that WPC‐emulsion possesses the lowest emulsification stability. The hydroperoxide value and reduction rate of the DHA content were higher in the WPC‐emulsions than in the Tween80‐ and Tween80 + Span80‐emulsions during storage, which suggested that the WPC‐emulsion had the lowest oxidation stability. CONCLUSION The DAG‐rich algae oil‐in‐water emulsion prepared with suitable emulsifiers, such as non‐ionic emulsifiers, would have excellent emulsification and oxidative stabilities and provides a health benefit for special purposes in the food processing industry.