Chemical and physical properties of a sunflower oil with high levels of oleic and palmitic acids

High-oleic high-palmitic sunflower oil (HOHPSO) has been obtained from field-grown mutant sunflower seeds CAS-12. The fatty acid and triacylglycerol compositions, the thermo-oxidative stability and the physical properties of the HOHPSO were determined and compared with those of the conventional and high oleic sunflower oils and those of a liquid fraction of palm oil (olein). The major fatty acids of the HOHPSO were monoenes (57.7% oleic, 7.3% palmitoleic) and palmitic (27, 8%), while the content of linoleic acid was low (2.3%). The saturated fatty acids were almost absent from the sn-2 position and, thus, the major triacylglycerol (TAG) molecular species were those with one or two saturated fatty acids at the sn-1, 3 positions and oleic acid at the sn-2 position (mainly POO and POP). Total polar compounds and their distribution in oxidised TAG monomers and TAG polymers were determined after 10 h at 180 °C. The HOHPSO showed enhanced thermal stability, producing half the amount of total polar compounds, and much less TAG polymers, as the palm olein. The stability index (Rancimat) of the HOHPSO was unusually high (19 h at 120 °C). The thermal properties of the HOHPSO (determined from the differential scanning calorimetry thermograms) were different from those of the palm olein. The HOHPSO presents lower solid fat con-tents than the palm olein above 15 °C and hence remains liquid at common working temperatures.The work was supported by grant 1FD97- 1023 from MCYT (Spain)