Composite beeswax-glycerol monolaurate oleogelation enhances encapsulation efficiency and oxidative stability of...

Microencapsulation of Antarctic krill oil (AKO) presents a unique challenge not encountered with conventional fish oils: the abundant endogenous phospholipids, while nutritionally valuable, are amphiphilic and competitively adsorb at the oil-water interface during emulsification and spray-drying. This interfacial competition disrupts wall material organization, promotes oil migration to the particle surface, and ultimately compromises encapsulation efficiency and oxidative stability. This study demonstrates that oil-phase pre-structuring via oleogelation using a composite beeswax/glycerol monolaurate (BW/GML) system effectively mitigates this problem. Endogenous phospholipids in Antarctic krill oil inherently migrate to the oil-water interface during emulsification and spray-drying, compromising microcapsule integrity. To mitigate this disruptive interfacial behavior, an oil-phase pre-structuring strategy via oleogelation was employed. This approach is proposed to physically constrain phospholipid migration by immobilizing the lipid core, thereby enhancing both encapsulation efficiency and oxidative stability. Results showed that a high BW/GML ratio (3,1) induced a robust crystalline network that effectively sequestered the oil phase. This structured core enabled uniform emulsion formation and yielded microcapsules with superior encapsulation efficiency (94.92% vs. 73.18% for non-gelled AKO), dramatically reduced surface oil (1.24% vs. 6.08%), and enhanced oxidative stability (peroxide value: 3.76 vs. 5.45 mg CHP/g oil after 12 days at 60 °C). Furthermore, during simulated intestinal digestion, oleogelation modulated lipolysis from a rapid burst to a controlled release, reducing total FFA liberation from 76.48% to 43.67%, while enhancing the bioaccessibility of EPA (90.46%) and DHA (60.50%), defined as their efficiency of incorporation into the mixed micellar phase. This work establishes oleogelation as an effective strategy to overcome phospholipid-induced interfacial competition, offering a robust platform for delivering nutritionally valuable but technologically challenging phospholipid-rich oils.