Oil thistles, or more precisely safflower thistles (botanically Carthamus tinctorius), are mostly annual representatives of the composite plants (Asteraceae). The thorny plants reach a height of between 50 and 130 centimeters. Their bright orange-red composite inflorescences of about 4 centimeters in diameter are characteristic. Its taproot does best in loose, deep soil. Otherwise, safflower is heat-loving but quite frugal, frost-resistant, and heat- and drought-resistant. Botrytis infestation can occur in wet conditions. The main use is for the numerous nut-like achenes, which are about 7 millimeters long and each contain an oily seed. Safflower oil accounts for 30 plus/minus 10 percent of the fruit dry matter.
The original form of the safflower thistle no longer exists today. Domestication probably took place well over 4000 years ago. According to population genetic research, it originated from the wild species Carthamus palaestinus in the Middle East. From there, people spread 5 to 7 cultivated varieties to the east and west in the so-called Fertile Crescent north of the Arabian Peninsula. Meanwhile, the cultivation areas are also distributed to temperate climates worldwide.
In 2019, more than half of the 45,000 tons of world exports of safflower oil (safflower oil) came from Ukraine, with the U.S. supplying just under 16,000. Mexico, Poland and India exported far less, while Germany is still the sixth largest supplier.
Depending on the climatic conditions of the growing area, summer and winter cultivation are practiced. The flowering period in this country ranges from July to August. After a growing period of about 5 months, harvesting takes place in late summer by means of combine threshing. Before further processing, the fruits require a cool drying period of several months.
Cold-pressed safflower oil of the original "linoleic" variety contains 68 to 83 percent esterified linoleic acid, an extremely high proportion among vegetable oils. This doubly unsaturated omega-6 fatty acid (C18:2, n-6) then also characterizes the physicochemical properties such as smoke point 150 to 160 degrees Celsius, iodine value 90 to 150. Although not highly heatable, safflower oil is nevertheless very stable against oxidation (2.9 hours). Oleic acid (18:1, n-9) accounts for an average of 10 percent, followed by the saturated representatives palmitic acid and stearic acid. Omega-3 fatty acids are completely absent. In addition, safflower oil is a source of vitamin E (alpha- and gamma-tocopherol), vitamin A and phytosterols.
As an edible oil, virgin safflower oil is valuable for its richness in essential linoleic acid, because polyunsaturated fatty acids can lower blood lipid levels. This is an established medical therapeutic use in hypercholesterolemia. However, it should only be used cold and as a supplement to "omega-3 oils". The DGE (German Nutrition Society) recommends a ratio between omega-6 and omega-3 fatty acids of no more than 5 to 1, since more predominant linoleic acid leads to increased formation of inflammation- and clotting-promoting eicosanoids. In terms of taste, virgin safflower oil is close to sunflower oil and is yellow to golden yellow in color.
In the safflower new varieties "oleic" and "high oleic", the ratio of linoleic to oleic acid is reversed and thus more similar to olive oil. When cold-pressed, these varieties are also suitable for frying.
Depending on the process and specification, safflower oil raffinates are tasteless and odorless, high-heat frying oil, pharmaceutical raw material for topical formulations, or cosmetic base material - also for soaps. Cosmetic as well as pharmaceutical manufacturers particularly appreciate some specifications of safflower oil: low viscosity, suitable also for acne or seborrhea, neither comedogenic nor film-forming, soothing and fast absorbing. Alpha-tocopherol also has antioxidant effects possible for the skin.
Hot-pressed safflower oil can be used as a technical raw material for varnishes and lacquers, as it is one of the slow-hardening oils. Afridi wax, boiled safflower oil, can be used to make linoleum. It is also suitable as a fuel (bio diesel).
Safflower is not the only supplier of safflower oil, although it is the most important. Other thistle oils come, for example, from the seeds of the widespread nodding thistle Carduus nutans, the common ass thistle Onopordum acanthium or the ornamental plant Echinops ritro (Ruthenian globe thistle).
The dried tubular flowers are also called false saffron, because they are visually difficult to distinguish from the precious original spice. They served as an important dye, especially in the Middle Ages. Their red dye, carthamine (saffron), colors natural fibers, and to this day also cosmetics and foodstuffs. Because of its attractive inflorescences, safflower is also a popular ornamental plant.