CONICET | Buscador de Institutos y Recursos Humanos

It is believed that conjugated linoleic acid (CLA)isomers have beneficial biological effects, which include the reduction of bodyfat content and mass muscle increment, stimulation of the immune system,inhibition of carcinogenesis. The aim of the present work was to formulateCLA-loaded liposomes for food aplications, to characterize them in size and toevaluate membrane fluidity. Liposomes were formulated following the techniqueof ethanol injection, utilizing soy phosphatidylcholine and conjugated linoleicacid isomers (9c, 11t and 10t, 12c) attwo different ratios (A and B formulations, protected information). Controls (Aand B) without CLA were included. Size distribution was measured by dynamiclight scattering, efficiency by gas chromatography, and membrane fluidity byelectron paramagnetic resonance (EPR) utilizing 5 SASL and 16 SASL spin labels.As for size, formulation B had the highest medium diameter (271.87± 13.25 nm),followed by formulation A (203± 1.33), which not differ from control A (197.53± 16.12 nm) and control B (153.00 ±5.52). CLA encapsulation efficiencies wereover 80 %, similar between formulations. Regarding membrane fluidity ofCLA-liposomes, two behaviors were noticed. With 5 SASL, sensing the outerportion of the lipid bilayer, both CLA formulations showed higher membranefluidity than controls. When employing 16 SASL, which senses the inner portionof the bilayer, formulation A did not differed from controls, but formulation Bshowed decreased fluidity. In summary, CLA at both formulations disorders theouter membrane zone increasing its fluidity, but formulation B causes adecreased fluidity near the center of the membrane. The results could haveimplications in fatty acids digestibility; and they constitute a preliminarystudy with a view of potential applications in food formulations.