The low saturated fat and high Vitamin E content makes sunflower seed oil one of the best vegetable oil options for healthy eating. The oil must be extracted to separate it from the solids using one of several processes. Three types of sunflower oil produced for cooking applications, which vary in oleic levels, are: NuSun, linoleic and high oleic. Oil-seed-type sunflower seeds are used for oil production rather than for common snack seeds.
Sunflower Oil Extraction
Warm and cold presses extract oil from sunflower seeds with slightly different flavors in the finished product. In a cold press, the hulls are removed; the seeds are broken into smaller pieces and run through steel rollers or a piston-like cylinder to squeeze out the oil. The resulting oil is usually labeled as "extra-virgin" sunflower oil, but the process leaves much of the oil behind in the seeds. Warm presses work much the same as cold presses, but the seeds are heated slightly before passing through the press for extraction. The heat lowers the viscosity of the oil so it flows more easily from the seeds when pressed; think the flow of refrigerated honey versus the flow of microwaved honey. Warm pressing results in more extracted oil, but the flavor differs slightly, similar to the difference between roasted or unroasted nuts. In some cases, a chemical called "hexane" is applied to the seeds to increase the amount of oil that can be extracted. After pressing seeds through the cold or warm press method, hexane might be applied to help extract any remaining oil from the seeds. The extracted oil is boiled so the hexane evaporates, processed with lye to remove the chemical taste, then steamed and heated to remove the lye taste.