Design and Characterization of Food-Grade Liposomes for Enhanced Food Function and Delivery of p-Coumaric Acid...

This study evaluated liposomes prepared using three food-grade lecithins-SLP-WHITE and SLP-PC70 (soy-derived), and PL-30S (egg yolk-derived)-to enhance the food function and delivery of p-coumaric acid (CA), a phenolic antioxidant extracted from sugarcane bagasse. Among the tested formulations, liposomes composed of SLP-WHITE and PL-30S at a 90:10 (w/w) ratio exhibited the highest encapsulation efficiency (82%). Notably, dynamic light scattering and confocal laser scanning microscopy revealed a strong negative zeta potential (-75.26 mV), small particle size (~100 nm), and a unilamellar structure, confirming this formulation as the optimum condition. Interestingly, encapsulated CA prepared with this optimum combination retained its antioxidant activity for 28 days. Furthermore, in a Caco-2 monolayer model, the liposomal CA showed significantly improved intestinal permeability compared to free CA, suggesting enhanced bioavailability via endocytic uptake. These results demonstrate that rational combinations of food-grade lecithins with complementary characteristics-such as the electrostatic stability of SLP-WHITE and membrane rigidity from PL-30S-can improve both physical stability and functionality of liposomes. This study provides a practical strategy for developing functional liposomal carriers suitable for food applications, particularly for delivering poorly bioavailable phenolic compounds like p-coumaric acid.