Those who cook with sunflower oil may have noticed in recent years that some brands are now labeled as "mid-oleic." This refers to the balance between polyunsaturated and monounsaturated fats in the oil, which are linoleic acid and oleic acid, respectively. Mid-oleic oils are the result of an initiative by the sunflower industry to move away from hydrogenation, which causes trans fat.
Traditional Linoleic Sunflower Oil
Traditional sunflower oils have fallen into two categories, one high in oleic acid and the other in linoleic acid. Linoleic acid is one of the essential fatty acids in the human diet, and linoleic varieties of sunflower oil contain nearly 70 percent polyunsaturated linoleic acid. Another 20 percent is in monounsaturated oleic acid, and the remaining 10 to 11 percent is saturated fat.
Traditional High-Oleic Sunflower Oil
High-oleic sunflower oil is radically different in its makeup. It consists primarily of monounsaturated oleic acids, at around 80 percent of the total. Saturated fats and polyunsaturated linoleic acid make up the balance, in equal proportions. High-oleic sunflower oil is important in the manufacture of food products, because it remains stable without hydrogenation and will not go rancid in long storage. This makes switching from linoleic to high-oleic sunflower oil an easy way for manufacturers to reduce trans fats.
Mid-Oleic Sunflower Oil
Mid-oleic sunflower oil takes a middle position between the two traditional oils, with oleic acid accounting for roughly two-thirds of the fat content, polyunsaturated linoleic acid at roughly 25 percent, and about 9 percent saturated fat. Mid-oleic oil retains high enough levels of linoleic acid to remain an excellent dietary source, but the relatively high levels of oleic acid make it less prone to rancidity and breaking down, eliminating any need for hydrogenation and the resulting trans fat.
Development of Mid-Oleic Oil
Mid-oleic oil is not the result of genetic engineering, but straightforward, old-fashioned hybridization. Researchers at various agricultural concerns cross-bred linoleic and high-oleic cultivars until they were able to produce a sunflower that consistently produced the desired levels of poly- and monounsaturates. The industry's producers trademarked the name "NuSun" to differentiate the new sunflower and its oil from those already on the market.