Improvement Effect of Soy Lecithin on the Stability and Delivery Efficiency of Ternary Interfacial Stabilized Emulsions

ABSTRACT The combination of soybean lecithin (SL), mono‐/di‐fatty acid glycerides, and proteins has been reported to notably enhance the stability and delivery efficiency of emulsions. Due to the complexity of SL, we here investigated the effect of three commercial SLs (SLA, SLB, and SLC) on the structural properties and lutein delivery efficiency of whey protein isolate (WPI)‐SL‐glyceryl monooleate (GMO) co‐stabilized emulsion. SLA, which contains a higher proportion of zwitterionic phospholipid, exhibited superior emulsion stability under pH and salt ion strength compared to SLB and SLC, which were enriched in more anionic phospholipids. Incorporating SLs at optimal concentrations significantly enhanced lipid digestion and lutein delivery performance compared to WPI emulsion. Specifically, in the presence of SLs, free fatty acid release increased from 26.86% to 45.52%, lutein digestive stability improved from 36.16% to 80.99%, lutein bioaccessibility increased from 58.44% to 85.55%, and delivery efficiency rose from 14.54% to 54.97%. Among the SLs, SLC with a high phosphatidylethanolamine content demonstrated the greatest reduction in interfacial tension and the highest delivery efficiency of lutein after digestion. These findings highlight the importance of lecithin compositional profiling in the design of emulsion‐based delivery systems for improved bioavailability of lipophilic bioactives.