Sunflower seed
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The sunflower seed is the seed of the sunflower (Helianthus annuus).
These seeds have been cultivated for several thousand years, originally in Mexico and Peru. They have been used by Native Americans for more than 5,000 years. They were brought to Europe by the Spanish conquerors.
Sunflower seeds are both eaten whole and pressed to produce sunflower oil. Sunflower seeds are tasty and rich in fibers and polyunsaturated fatty acids (about 66 % linoleic acid) and low in saturated acids, such as palmitic acid and stearic acid. They are processed into polyunsaturated margarines. Nowadays, sunflower oil is one of the most popular oils in the world.
Sunflower seeds in achenes with striped pericarps (= fruit wall) are used primarily for food. Seeds from achenes with solid black pericarps are pressed into sunflower oil.
Sunflower seeds are more often eaten as a healthy snack than as part of a meal. They are particularly popular in Mediterranean countries. When eaten whole, the seeds are first dried. They may be roasted and for better preservation they are often covered with salt or flour.
Sunflower seeds are sometimes added to bread and other baked goods, for their flavor.
Apart from human consumption, sunflower seeds are also sold as food for pet and wild birds. The pressed sunflower seed cake constitutes a valuable livestock feed, rich in proteins.
Furthermore, sunflower oil could become in the future a renewable, eco-friendly energy source, as an important bio-source for hydrogen. A team for the University of Leeds has developed a workable method for the extraction of hydrogen from sunflower oil, through a chain of chemical reactions with nickel and carbon-based catalysts.