Development and characterization of sunflower-chia oil blends

SUSANA M. NOLASCO ; IXTAINA, VANESA Y..; ESTEFANIA N. GUIOTTO; MC TOMAS

Sevilla

Conferencia; 2nd International Conference of Chia-Link Network; 2016

Instituto de la Grasa CSIC

Chia (Salvia hispanica L.) seed oil is an interesting source of polyunsaturated fatty acids (PUFA), containing the highest content of α-linolenic acid (~60%) of any known vegetable source. PUFA oxidation generates volatile compounds that impart undesirable flavors and aromas, limiting its shelf life. The mixture of different proportions of chia with sunflower oil provides a simple method to formulate oil blends with a special composition to improve their stability and nutritional value. FAO/WHO has recommended that essential ω-6:ω-3 FA balance should be between 5:1 and 10:1 on intake. The aim of this work was to study the effect of the addition of antioxidants (Rosemary extract, ascorbyl palmitate and their mixture) on the oxidative stability of sunflower-chia seed oil blends from Argentina in order to evaluate its functionality for the food industry. Sunflower-chia (90:10 and 80:20 wt/wt) oil blends with the addition of rosemary (ROS), ascorbyl palmitate (AP) and their blends (AP:ROS) were formulated to evaluate the oxidative stability using different methods (DSC, Rancimat, PV, p-anisidine) during storage at two temperature levels normally used, cooling (4±1 °C) and room temperature (20±2 °C) for a period of 360 days. Sunflower-chia blends 80:20 and 90:10 wt/wt contain about 17.4 and 9.0% of α-linolenic acid, corresponding to ω-6:ω-3 relationship ranging from 2.7:1 to 5.3:1, respectively. Peroxide values (PV) of the oil blends with antioxidants stored at 4±1 ºC showed levels ≤ 10.0 meq O2/kg oil; the lowest levels of PV were found for blends with AP:ROS. Values higher than 10.0 meq O2/kg were observed between 120-240 days for oil blends stored at 20±2 ºC. Similar trends were observed with p-anisidine and Totox values. The oxidative stability determined by the Rancimat method and differential scanning calorimetry (DSC) showed a greater susceptibility of the oils to oxidative deterioration with increasing unsaturated fatty acids content. The fatty acid composition corresponding to sunflower-chia oil blends indicates that the essential fatty acids balance ω-6/ω-3 can be achieved with a low proportion chia oil (10 and 20% wt/wt). Temperature had a strong influence on oil oxidation. DSC study showed that ROS had the best antioxidant effect, whereas AP:ROS was the most effective antioxidant during storage at 4±1 °C according to Rancimat tests and PV, p-AV and Totox values.