|Small Scale Processing of Oilfruits and Oilseeds (GTZ, 1989, 100 p.)|
|1. Oil Plants and their Potential Use|
|1.2 The major oil plants|
The sunflower, Helianthus annuus L., is a member of the Compositae, a large and successful family of flowering plants occurring throughout the world. The genus Helianthus is named from the Greek hellos meaning sun, and anthos flower.
Figure 6: Sunflower.
Source: KIT, 1979
Basically a temperate-zone plant, the main commercial production of sunflower is in the warm-temperate regions but breeding and selection have produced varieties adapted to a wide range of environments. Optimal conditions are short, hot (around 27ºC) summers with not too much rain (around 250 mm) during flowering and fructification. Greatest production is between latitudes of 200 to 500 north and 200 to 400 in the southern hemisphere, usually below altitudes of 1 500 m.
Sunflower is the only crop of worldwide commercial importance that originates from the area of the USA (probably south-western states to Mexico). Earlier used for food by the Indians of that region, it was already cultivated when the Europeans arrived in North America. The post-war introduction of Russian varieties, which not only pushed the oil content of the seeds to 50 % but were suitable for mechanized harvesting (90 to 150 cm high), had an immense impact on the development of sunflower as a commercial crop in Europe and the Americas.
Today, world production of sunflower ranks fifth among oil seeds and third among the vegetable oils (see Tables 1 and 2). In world trade, it has established an equally important position, although a significant portion of the production in developing countries is for personal consumption and therefore not registered. World production of sunflower seeds was dominated by the USSR which used to account for 50 %, but has declined since the 1970's to roughly half that share or 5 million tons in absolute terms. Other major producers are now Argentina (3.4 million tons), China (1.9), France (1.5) and the USA (1.4). Argentina has also become the leading exporter of sunflower oil and now accounts for almost half the world trade.
The cultivated sunflower is a tall, erect, unbranched, coarse annual, with a distinctive large, golden head. The plant grows rapidly, the stem varying in height from I to 3m when full grown with individual plants of giant varieties reaching 5m. New hybrids have a shorter stem and are remarkably even in growth and final height (within 5 % deviation). The discshaped head is born terminally on the main stem and branches where these occur and is commonly 10 to 30 cm in diameter.
- The fruit, or sunflower seed, ranges in colour from black through to white, but brown, striped or mottled seed can also occur. Seed varies greatly in size and weight, but is generally a compressed, flattish oblong. Average seed yields are currently 1.3 tons per ha, but can reach up to 4 tons/ha. The oil content of sunflower seed is between 25 and 48 %, but can reach 65 % under experimental conditions. Important for developing countries is the fact that high temperatures during seed development can reduce the total oil content to below 25 %, which would make small-scale processing less rewarding.
Sunflower oil, which is pressed in a cold stage, is a very highly valued salad oil; lower qualities are also used for technical purposes (paints).