Biodiesel fuel is gaining more and more importance because of the depletion and uncontrollable prices of fossil fuel resources. The use of vegetable oil and their derivatives as alternatives for diesel fuel is the best answer and as old as Diesel Engine. Chemically biodiesel fuel is the mono alkyl esters of fatty acids derived from renewable feed stocks like vegetable oils and animal fats. Safflower oil contains 75-80% of linoleic acid; the presence of this unsaturated fatty acid is useful in alleviating low temperature properties like pour point, cloud point and cold filter plugging point

Safflower (Carthamus tinctorius) is a highly branched, herbaceous, thistle-like annual, usually with many long sharp spines on the leaves. Plants are 30 to 150 cm tall with globular flower heads and commonly, brilliant yellow, orange or red flowers which bloom in July. Each branch will usually have from one to five flower heads containing 15 to 20 seeds per head. Safflower has a strong taproot which enables it to thrive in dry climates, but the plant is very susceptible to frost injury from stem elongation to maturity.

Safflower, is a member of the family Compositae or Asteraceae, cultivated mainly for its seed, which is used as edible oil and as birdseed.

Traditionally, the crop was grown for its flowers, used for colouring and flavouring foods and making dyes, especially before cheaper aniline dyes became available, and in medicines.

In India the crop has traditionally been grown in the 'rabi' or winter dry season in mixtures with other 'rabi' crops, such as wheat and sorghum. After emergence, the crop maintains a rosette form for some weeks before rapid elongation to mature height. The florets are self-pollinating but seed set can be increased by bees or other insects.

Safflower is one of humanity's oldest crops, but generally it has been grown on small plots for the grower's personal use and it remains a minor crop with world seed production around 800 000 t per year (Gyulai 1996). Oil has been produced commercially and for export for about 50 years, first as an oil source for the paint industry, now for its edible oil for cooking, margarine and salad oil. Over 60 countries grow safflower, but over half is produced in India (mainly for the domestic vegetable oil market). Production in the USA, Mexico, Ethiopia, Argentina and Australia comprises most of the remainder. China has a significant area planted to safflower, but the florets are harvested for use in traditional medicines and the crop is not reported internationally.

There are two types of safflower varieties, the type that produces oil which is high in monounsaturated fatty acids (oleic acid), and those with high concentrations of polyunsaturated fatty acids (linoleic acid). Either type of safflower raised in the Northern Great Plains is very low in saturated fatty acids when compared to other vegetable oils. Only the linoleic safflower is being grown commercially in the Upper Midwest. Varieties with a high content of oleic acid may soon be grown more widely.

Uses

Safflower was originally grown for the flowers that were used in making red and yellow dyes for clothing and food preparation. Today this crop supplies oil, meal, birdseed, and foots (residue from oil processing) for the food and industrial products markets, although this crop is now primarily grown for the oil.

The oil in linoleic safflower contains nearly 75% linoleic acid, which is considerably higher than corn, soybean, cottonseed, peanut or olive oils. This type of safflower is used primarily for edible oil products such as salad oils and soft margarines. Researchers disagree on whether oils high in polyunsaturated acids, like linoleic acid, help decrease blood cholesterol and the related heart and circulatory problems. Nonetheless, it is considered a "high quality" edible oil and public concern about this topic made safflower an important crop for vegetable oil.

Varieties that are high in oleic acid may serve as a heat-stable, but expensive cooking oil used to fry potato chips and french fries. As an industrial oil, it is considered a drying or semidrying oil that is used in manufacturing paints and other surface coatings. The oil is light in color and will not yellow with aging, hence it is used in white and light-colored paints. This oil can also be used as a diesel fuel substitute, but like most vegetable oils, is currently too expensive for this use.

The meal that remains after oil extraction is used as a protein supplement for livestock. The meal usually contains about 24% protein and much fiber. Decorticated meal (most of hulls removed) has about 40% protein with a reduced fiber content. Foots are used to manufacture soap. The birdseed industry buys a small portion of the seed production. Sheep and cattle can graze succulent safflower and stubble fields after harvest.

Climate

Safflower production is not recommended for areas with more than 15 in. of annual precipitation or growing seasons with fewer than 120 frost-free days and less than 2,200 growing degree days. Temperatures as low as 20°F are tolerated by plants while in the rosette stage, but safflower is very sensitive to frost injury after stem elongation until crop maturity. This crop does best in areas with warm temperatures and sunny, dry conditions during the flowering and seed-filling periods. Yields are lower under humid or rainy conditions since seed set is reduced and the occurrence of leaf spot and head rot diseases increases. Consequently, this crop is adapted to semiarid regions. Most areas of Minnesota and Wisconsin are not well suited for safflower.

Soil

Deep, fertile, well-drained soils that have a high waterholding capacity and high level of stored moisture are ideal for safflower. This crop is also productive on coarse-textured soils with low water-holding capacity when adequate rainfall or moisture distribution is present. Soils that crust easily can prevent good stand establishment. High levels of soil salinity can decrease the frequency of seed germination and lower seed yield and oil content. Safflower has approximately the same tolerance to soil salinity as barley.