Physicochemical Stability of Chia Seed Oil Bi-layer Emulsions

NOLASCO, SUSANA M.; IXTAINA, VANESA Y.; JULIO, LUCIANA M.; TOMÁS, MABEL C.

Salt Lake City

Congreso; 107th AOCS Annual Meeting & Expo; 2016

American Oil Chemists' Society

The development of multilayer emulsions with chia oil is very interesting since this oil is sensitive to lipid oxidation due to its high omega-3 content. This emerging method based on the electrostatic layer-by-layer deposition provides interfacial layers of greater thickness around the oil improving its stability. A primary (lecithin, Lec) and secondary emulsion (Lec+chitosan) was prepared by homogenizing 5% wt chia oil with 95% wt aqueous solution (600 bar), pH3, stored ~1 month at 4.0±0.5°C. Emulsions were evaluated by confocal microscopy, ζ-potential, apparent viscosity and the evolution of backscattering profiles, particle size distribution, mean diameter (D[4,3]) and peroxide value (PV). Surface charge changed from -37 to 46 mV when chitosan was added. The particle size distribution was monomodal for the two-layer emulsions, whereas the mono-layer emulsions presented a little shoulder. The initial D[3,2] was 0.32µm and 0.26µm for mono and bi-layer emulsions, respectively. Mono-layer emulsions recorded some signs of destabilization after 20 days of storage, while bi-layer emulsions were physically stable during this period. As determined by PV, bi-layer systems of Lec and chitosan were more stable than those with Lec alone. These data suggest that multilayer emulsion could be an effective technology to deliver chia oil into functional foods.