Synergistic antioxidant effect of glutathione and edible phenolic acids and improvement of the activity protection by coencapsulation into chitosan-coated liposomes

Reduced glutathione (GSH) and some food-derived phenolic acids are welcome as natural antioxidants, but their synergistic antioxidant effect is unknown. The purpose of this study was to screen out the combination of GSH and the phenolic acid with synergistic antioxidant effect, improve their coexistence and protect the activity. Antioxidant evaluation systems including ABTS, DPPH, ORAC and reducing power assays were implemented, and dynamic light scattering and transmission electron microscopy analysis were carried out. Caffeic acid (CA) and GSH exhibited significant synergistic effect via electron transfer when the concentration ratio was 1:5. This combination was well embedded into chitosan-coated liposomes, which consist of evenly distributed and uniformly spherical microparticles, and its average particle size was 247.63 nm with polymer dispersity index of 0.29 and zeta potential of 57.73 mV. The encapsulation efficiencies of GSH and CA were 61.32% and 68.92%, respectively. The successfully prepared microparticles showed higher markedly antioxidant activity than the simple mixture and liposomes in 10-week storage. Therefore, co-encapsulation of GSH and CA using chitosan-coated liposomes is a potential approach to prepare natural potent antioxidant in food manufacture.