Submitted to: Helia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 3, 2002
Publication Date: July 1, 2002
Citation: SEILER, G.J. WILD PERENNIAL SUNFLOWER AS A POTENTIAL SOURCE OF REDUCED PALMITIC AND STEARIC FATTY ACIDS IN SUNFLOWER OIL. HELIA. 2002. V. 25 (36). P. 79-84. Interpretive Summary: In recent years consumers have become more concerned about the consumption of saturated fats in their diet. High levels of saturated fat consumption may contribute an increase in blood serum cholesterol, and high blood serum cholesterol increases the risk of coronary heart disease. Prompted by nutritional recommendations to consume fats lower in saturates and food manufacturers¿ interest in reducing the use of hydrogenated oil, food processors have become interested in oils with specific fatty acid profiles. Vegetable oils are the principal source of fats in many diets. Compared to other edible vegetable oils, the saturated fatty acid concentration in sunflower oil of 12% is considered moderate, with the principal saturated fatty acids being palmitic (6.5%) and stearic (4.5%) acids. Canola oil has only 4% palmitic and 2% stearic acids which is considered low in saturated fats. A reduction of saturated fatty acids in sunflower oil to the 6 to 8% level would increase the acceptability of sunflower oil as a healthier edible oil. The genus Helianthus contains 50 species, 36 perennial and 14 annual. Wild sunflower species serve as a potential resource for improving fatty acid composition in cultivated sunflower. Achene oil of one population of wild perennial H. giganteus (GIG-102) from INRA, Montpellier, France, had a palmitic acid level that averaged 4.7%, while stearic acid averaged 1.8%. The combined 6.5% palmitic and stearic acids is 40% lower than the present level of these fats in sunflower oil. When grown in the greenhouse, the saturated palmitic acid averaged 4.8%, while stearic acid averaged 1.6%, similar to the original population. This would indicate that palmitic and stearic acids have a genetic base with the potential for selection and incorporation into cultivated sunflower. Crossing this population with an inbred cultivated line produced early generation plants with achene oil that averaged 4.7% palmitic and 2.8% stearic acid, for a total of 7.5%. The inbred cultivated parent averaged 5.4% palmitic and 5.6% stearic acid totaling 11.0%. Preliminary information indicates that palmitic and stearic fatty acids in sunflower oil can be reduced by introducing genes from a population of a wild perennial progenitor into cultivated sunflower. Further research will be needed to determine the inheritance of these fatty acids. Acceptable agronomic traits will also have to be bred into the lines and monitored during the introduction of the genes into cultivated sunflower.
Technical Abstract: The trend in healthier human diets is to decrease the consumption of the saturated fatty acids. Sunflower oil, which is fourth in production among edible vegetable oils in the world, contains 65 g kg-1 palmitic and 45 g kg-1 stearic acids, both saturated fatty acids. These levels are high compared to rapeseed (Brassica napus L.) oil with 40 g kg-1 palmitic and 20 g kg-1 stearic acids. A reduction of saturated fats in traditional sunflower oil would lead to a healthier edible oil. The objective of this preliminary study was to search the vast genetic diversity available from wild ancestors of cultivated sunflower for potential sources of reduced palmitic and stearic fatty acids. Achene oil of one population of wild perennial H. giganteus L. (GIG-102) from INRA, Montpellier, France had 47 g kg-1 palmitic acid and 18 g kg-1 stearic acid. The combined 65 g kg-1 palmitic and stearic acids is 40% lower than the present level of these fats in sunflower oil. The level of saturated fatty acids observed in the population remained low when plants were grown in the greenhouse under uniform conditions. In the greenhouse, palmitic acid averaged 48 g kg-1, while stearic acid averaged 16 g kg-1. This would indicate that palmitic and stearic acid concentrations are under genetic control with potential for incorporation into cultivated sunflower. Crossing this population with an inbred cultivated line produced F1 plants with achene oil that averaged 39 g kg-1 palmitic and 26 g kg-1 stearic acid. The inbred cultivated parent averaged 55 g kg-1 palmitic and 51 g kg-1 stearic acid. F2 plants produced achene oil that averaged 47 g kg-1 palmitic and 29 g kg-1 stearic acid, for a total of 76 g kg-1. When F1 plants were backcrossed to the cultivated inbred, BC1F1 plants produced an achene oil that averaged 47 g kg-1 palmitic and 28 g kg-1 stearic acid for a total of 75 g kg-1. The inbred cultivated parent averaged 54 g kg-1 palmitic and 56 g kg-1 stearic acid, for a total of 110 g kg-1. Preliminary information indicates that introducing genes from a wild perennial progenitor into cultivated sunflower can reduce palmitic and stearic fatty acids in sunflower oil. Further research will be needed to determine the inheritance of these fatty acids. Other agronomic traits will also have to be monitored during the introgression of genes for reduced saturated fatty acids into cultivated sunflower.