Combination of natural strategies to improve the oxidative stability of echium seed oil.

Echium seed oil is an alternative source of omega 3 fatty acids but it is highly susceptible to oxidation. A combination of three natural strategies was proposed in this study aiming to improve the oxidative stability of echium oil obtained by pressing (PO) or solvent extraction (PSO), kept in the storage condition for 180 days or during the consumption for 30 days. Our results showed that the reduction of temperature was sufficient to keep the oil stable during storage for both samples. During the consumption time, the best stability was achieved by adding a mixture of antioxidants, composed of sinapic (500 ppm), ascorbic (250 ppm), and citric (150 ppm) acids, and/or 20% of high oleic sunflower oil. The combined strategies promoted a 34 to 80% reduction of peroxide value and 0 to 85% reduction of malondialdehyde concentrations in the samples, showing to be a feasible and natural alternative to improve the oxidative stability of echium oil. PRACTICAL APPLICATION: Our study successfully applied an optimized combination of simple and low-cost strategies to enhance the chemical stability of echium seed oil. As the use of echium oil expands around the world, the oil industry and final consumers may benefit from our results to increase the oil shelf-life.

Effect of sinapic acid ester derivatives on the oxidative stability of omega-3 fatty acids rich oil-in-water emulsions.

Oil-in-water (O/W) emulsions are important delivery systems of omega-3 fatty acids (n-3 FA). We investigated the effect of sinapic acid esters concentration and chain length, the electrical charge of the emulsifier and emulsion pH on the oxidative stability of n-3 FA rich O/W emulsions. Echium oil was applied as n-3 FA source. A 24 factorial design was used to simultaneously evaluate these factors. Peroxide value, malondialdehyde, 2,4-heptadienal and 2,4-decadienal were measured in the emulsions. pH and the electrical charge of the emulsifier modulated the antioxidant effectiveness of sinapic acid esters, while concentration was not relevant. The combination of positively charged emulsifier with neutral pH provided the best oxidative stability for echium oil emulsions. Our results also suggested that the increase of length chain of sinapic acid, from C4 to C12, reduced the secondary products of oxidation, when echium oil emulsions were prepared using negatively charged emulsifier under acidic conditions.