Chia bilayer emulsions with modified sunflower lecithins and chitosan as delivery systems of omega-3 fatty acids

Chia oil constitutes a vegetal source of omega-3 polyunsaturated fatty acids (PUFAs) and natural antioxidants, although it is susceptible to the oxidation process. Emulsion-based delivery systems could be adequate for its protection and incorporation into foods. In this study chia bilayer O/W emulsions were obtained applying layer by-layer deposition technique. It consisted of the electrostatic deposition of positively charged chitosan on negatively charged oil droplets. These were stabilized using modified sunflower lecithins (deoiled or phosphatidylcholine-enriched) in presence or absence of maltodextrin. The particle size distribution, mean diameters, zeta-potential and viscosity of emulsions were determined. The chitosan addition had a strong influence (p <= 0.001) on the rheological properties increasing the viscosity and changing the flow behavior of emulsions. The global and oxidative stability of emulsions were monitored during 50 days at 4 degrees C. The bilayer emulsions showed better physical stability than the monolayer ones. Also, they recorded lower peroxide values (p <= 0.05) than mono layer systems and bulk chia oil, with no significant (p > 0.05) changes in their omega-3 PUFAs content during the storage period. Bilayer emulsions with modified sunflower lecithins proved to be protective systems against lipid oxidation, constituting a viable option for the delivery of chia omega-3 PUFAs with potential application in the food industry.