The objective of this study was the design of natural delivery systems for the composition of the essential polyunsaturated fatty acids (PUFA) with an adequate level of w-3/ w-6 (1/1÷2). Linseed oil was used as a main source of alpha-linolenic acid (ω -3: 54.5%; ω-6: 18.3%; ω-9: 15.7%). Two types of phospholipids, namely phosphatidylcholine, PC (ω-3: 3÷7%; ω-6: 59÷70%; ω -9: 11÷15%) and lisophosphatidylcholine, LPC (ω -3: 1%; ω -6: 44÷48 %; ω -9: 15÷17%) (Lipoid GmbH) were added, on the one hand, as low-molecular weight emulsifiers, and, on the other hand, as the main suppliers of the linoleic acid (ω-6). Sodium caseinate (SCN) (Sigma, New Zealand) or its covalent conjugate with maltodextrin (MD) (Paselli Md10, Avebe, the Netherlands) were added as additional biopolymer emulsifiers. Dynamic laser light scattering was used for the measurement of the mean droplet size of the formed nanoemulsions.
The extent of the oxidation of the polyunsaturated lipids in such nanoemulsions was followed during 28-day of their storage by measuring the quantity of the conjugated hydroperoxides and malonic dialdehyde. It was revealed that the linseed oil droplets, stabilized by PC, were much more stable in relation to oxidation in comparison with both linseed oil alone and linseed oil droplets stabilized by LPC. The best stability against oxidation was found for the nanoemulsions involving linseed oil, LPC and food biopolymers. As this takes place, the covalent conjugate provided the most effective protection against oxidation for the polyunsaturated lipids.
