Encapsulation of emulsions by a novel delivery system of fluid core–hard shell biopolymer particles to retard lipid oxidation
Colloidal delivery systems could be designed to retard lipid oxidation in foods, thereby extending their shelf-lives and improving their nutritional quality. In this study, a class of novel fluid core–hard shell biopolymer particles with lipid droplets being encapsulated in the biopolymer has been designed and fabricated to increase their lipid oxidative stability. This was achieved by injecting a mixture of Tween 80-coated lipid droplets, xanthan gum, and calcium ions into a sodium alginate solution at either pH 3 or 7. The viscosity, hardness, microstructure, physical stability, and chemical stability of the droplet-loaded fluid core–hard shell (FCHS) biopolymer particles were then measured. The results indicated that the FCHS biopolymer particles had thinner, denser, and harder shells at pH 3 than at pH 7. The thickness of the alginate biopolymer particle walls could be modulated by varying the xanthan gum to alginate ratio used during fabrication. The lipid oxidation measurements indicated that the primary (PV) and secondary (TBARS) reaction products decreased by approximately 60% and 75%, respectively, compared to the control after 13 days of storage at pH 3. These results indicate that the encapsulation of lipid droplets within the FCHS biopolymer particles substantially increased their oxidative stability. The biopolymer particles developed in this study may have promising applications in various food, pharmaceutical, and cosmetic products for retarding lipid oxidation.