Sunflower was considered as an ornamental flower until 19th century after that it was cultivated as an oil seed plant in Russia.
The sunflower is a member of the compositae family. The commercial varieties cultivated for seed purposes are grouped under Helianthus annuus variety macrocarpus. The cultivated sunflower contains 34 somatic chromosomes (2n=34).
Sunflower is mainly used for the extraction of soil. Defatted meal is the main by product of sunflower oil extraction and it is rich in protein and certain minerals. Defatted meal is mostly fed to animals and birds. The large seeded non-oil seed varieties normally provide feed for birds and also used as whole roasted seeds similar to peanuts. After dehulling, the kernels are sold as confectionery nuts.
Sunflower oil has high level of linoleic acid. Linoleic acid is required for the cell membrane structure, cholesterol transportation in the blood and for prolonged blood clotting. Sunflower oil helps to reduce the serum cholesterol levels. The presence of trypsin inhibitor has been observed in sunflower seeds. However, the activity of the inhibitor is extremely low. The inhibitor is heat-labile and inactivated easily.
The chemical composition of sunflower seed is comparable to that of groundnut. However, the composition varies widely due to genetic and environmental factors. A proximate composition of sunflower seed is presented in Table 1.
Proximate composition (% of sunflower seeds)
Most of lipids in the seed are present in kernels (87%) followed by embryo (74%) and least in the hull. The dehulled seeds (kernels) contain more oil than the whole seed. Sunflower oil is primarily comprised of palmitic, stearic, oleic and linoleic acid. It contains more unsaturated fatty acids than other oil seeds such as soybean, peanut and cotton seed.
No recommended variety is available. Spain, Sunfola and CO-2 are identified as promising lines.
Sunflower can be grown successfully in the dry zone as a rainfed crop in 'maha' season or as an irrigated crop in 'yala'.
Sunflower grows well on a wide range of well-drained soils from sandy loam to heavy clays.
Fertilizers are necessary for good yields. Nitrogen, the most important nutrient, is stored in the main stem and withdrawn when needed. Phosphate and potassium have an appreciable effect on yield only if sufficient nitrogen is available.
Basal- apply the following formulations and rates.
Harvesting & Post-harvest Technology
Most heads turn yellow at maturity
Harvest after petals drop but before seeds shatter.
After heads are dried in the sun, seeds can be separated easily by hand or multi-crop thresher with the capacity of 900 kg/ha.
Drying of seeds is the first step in sunflower seed processing. The moisture content of freshly harvested sunflower seeds may be as high as 20%. To ensure safe storage, the seeds must be dried to less than 10% moisture. Sunflower seed is decorticated before the oil is extracted to ensure that the cake is a nutritious animal feed.
Extraction of oil from sunflower seeds or kernels can be done using general equipments and operating conditions used for soybean or other oil seeds. The extraction of oil from sunflower is done by mechanical extraction, prepress solvent extraction and direct solvent extraction methods.Sunflower oil usually does not require extensive refining as it contains relatively low
levels of free fatty acids, phopholipids, tocopherols, pigments and sterols.
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