Capillary bridge-based oleogel using guar gum dispersed in soybean oil: Enhancement of gel stability by soy lecithin

Abstract Dietary solid fats are crucial for baked food quality but often high in unhealthy saturated and trans fats. This study developed a novel, food-grade capillary bridge-based oleogel using guar gum (GG) particles in soybean oil, with an aqueous phase containing soy lecithin (SL) as the secondary fluid, to structure liquid oil without chemical modification. The effects of GG concentration, secondary fluid content, and SL concentration on oleogel formation, properties, and oxidative stability were investigated. Interfacial tension measurements and contact angle analysis revealed that SL significantly reduced interfacial tension and modulated GG particle wettability, promoting a transition from a pendular to a denser capillary state, thereby strengthening the gel network. Rheological studies confirmed the solid-like behavior and enhanced mechanical stability of oleogels with higher SL concentration in aqueous phase. Furthermore, the improvement in the oxidative stability of oleogels with SL incorporation may be attributed to the formation of a protective network. Application tests in sponge cakes demonstrated that oleogels with high SL concentration (9 % and 15 %, v/v) in aqueous phase could effectively replace 50 % butter, yielding cakes with color, texture, and sensory profiles that were comparable to those of butter cakes, while significantly improving these characteristics compared to cakes made with soybean oil. This study provides a strategy for constructing oleogels as a potential alternative to solid fats in baked products. • A novel capillary oleogel was structured in soybean oil with GG particles and SL. • SL enhanced gel strength and oxidative stability by tuning interfacial properties. • High-SL oleogels (9–15 %) showed solid-like behavior and improved stability. • The oleogel replaced 50 % butter in sponge cakes with comparable sensory quality.