Background and methodology:
The study sought to highlight the differences between seed oils produced from conventionally cultivated sunflower crops and organically cultivated ones, as processed using mild extraction procedures. The composition and nutritional and health aspects of different sunflower oils were compared. Organic and conventional oils available on the market were analytically tested to determine:
- macroscopic differences in proximate composition;
- main qualitative/quantitative differences in the minor components (tocopherols, polyphenols, and b-sitosterol);
- main quality parameters (free acidity, peroxide number, induction time by Rancimat);
- in vitro antioxidant activity; and
- presence of trans-ethylene stereoisomers in FA.
Remarkable differences were found in the composition of minor components and in the main chemical and analytical quality properties. Free acidity, peroxide number and induction time showed statistically significant differences between organic and conventional oils.
Results indicated high free acidity and peroxide numbers in organic oils. The organic oils had the lowest a-tocopherol content determined in the unsaponifiable fraction. The induction time for the organic oils was shorter than for conventionally processed oils because of the high presence of b- and g-tocopherol.
The in vitro test for antioxidant activity showed that all the samples had a positive activity. This was probably due to the synergistic effect between a-tocopherol and total polyphenols.
The organic oils had a higher total antioxidant activity while conventional oils had poorer antioxidant activity. The organic oils had poorer quality parameters than conventional ones. This does not represent a direct risk to consumer health, but it does indicate that greater attention has to be given to processing and storage of the raw material and end products.
Perretti, G., Finotti, E., Adamuccio, S., Sera, R. D., & Montanari, L. (2004). Composition of organic and conventionally produced sunflower seed oil. Journal of the American Oil Chemists’ Society, 81(12), 1119-1123. Available on-line at: http://www.springerlink.com/content/8r6493g7573kx634/