Human beings have used seeds for oil for as long as human civilization has been around. As far back as 2,000 BC, rapeseed and sesame have been mentioned in writings from the Indian subcontinent. Even earlier, in 3,000 BC, sunflower was reported to be around in what is today Arizona and New Mexico.
What are oilseeds?
Seeds for oil - or oilseeds, as we commonly refer to them - are the seeds of plants cultivated primarily for their oil content. Nutritionally, every type of oilseed - be it sunflower, groundnut, sesame, pumpkin, soyabean, or rapeseed - has a distinct chemical composition, with different proportions of protein, fat, starch, water, vitamins (like vitamin E, niacin, and foliate) and minerals (like iron, phosphorus, and magnesium). For instance, sunflower seed meal (i.e. what's left after sunflower oil is extracted) contains 40 to 50% of protein content, while soyabean pressed cake boasts as much as 70% protein.
Seeds for oil extraction are selected for this purpose because of their nutritional profiles. In addition to the fats and proteins mentioned above, researchers have found that oilseeds are also rich in phytonutrients beneficial for human health. Particularly, because of their antioxidative and anti-inflammatory properties, omega-3 fatty acids, lignans, and phytosterols have been shown to help fight non-communicable diseases like cardiovascular disease, rheumatoid arthritis, diabetes, hypertension, obesity, and more.
Grown globally, seeds for oil extraction have also proven to be important economic crops. Oilseed processing using seeds oil extraction machines and allied equipment yields edible oils - the product for which oilseeds are cultivated in the first place. However, that's not all.
More than just oil…
Beyond the valuable edible oil, oilseed processing also yields a protein-rich meal or cake, which is used as a human protein source or as animal feed. Plant protein, as an economical and effective alternative to animal protein, has become increasingly popular. This popularity is also driven by the increasing preference for low-carbohydrate, high-protein diets to improve overall health and prevent or manage chronic diseases. The increasing demand for functional foods has also led to the development of novel food products fortified with bioactive ingredients found in seeds for oil.
Moreover, the extracted oil and other products from oilseed processing also have applications in the biodiesel and oleochemical industries. The demand for plant-based oils in non-food industries has risen so much, that many countries have begun to prioritise the cultivation of non-edible oilseeds for these industries. This prevents a conflict between food and other industries for the same agricultural raw materials.
On the whole, many factors affect which seeds for oil extraction are cultivated and processed. The culture and traditions of a region, people's income levels, flavour preferences, proximity to oilseed cultivation, and applications of the oils in question affect their production and consumption.
The need for seeds oil extraction machines
Many common seeds for oil extraction have chemicals or antinutrient components which may be negatively associated with human health. Some of these oils and the protein from their seeds may even be deficient in important vitamins, minerals and amino acids which could enhance people's well-being. These limitations can be overcome by either supplementation with other nutrients or tailored physico-chemical treatment, as can be achieved with seed cleaning machines, seeds oil extraction machines, and edible oil refining equipment.
Overall, oilseed processing techniques can be used to improve the quality of seeds for oil extraction to meet the increasing demand for healthy edible oils. Oilseed processing can enhance the oil yield and nutritional profile of the extracted edible oils, making it more acceptable and appealing to consumers.
Additionally, the oil extraction and processing techniques themselves affect the quality of the extracted oil and the residual meal or cake. Severe heat and ineffectively eliminated solvents can affect product quality, even destroying amino acids like lysine, arginine, methionine, and tryptophan. That's why choosing the right seeds oil extraction machine is so important.
The best seeds for oil extraction
According to Statista, of all the seeds for oil cultivated in the 2023/2024 crop year, soybean led the way globally, with over 398 million metric tonnes of soybeans forecast to be produced. In terms of worldwide production by mass, rapeseed was a distant second, followed by sunflower seed, peanuts, cottonseed, palm kernel, and copra.
Meanwhile, in 2021, the United States Department of Agriculture (USDA) stated that palm, soybean, rapeseed, sunflower seed, palm kernel, peanut, cottonseed, coconut, and olive oil were the major vegetable oils produced globally. Minor or unconventional oils from safflower, pumpkin, flaxseed, apricot, and chia, which have high oil content or bioactive compounds, were also produced for human consumption or industrial applications.
Soybean (Glycine max). The oil extracted from the seeds of the soyabean plant is among the most widely consumed cooking oils globally. After the seeds are cleaned, dried, dehulled, and extruded, oil is extracted from them predominantly via mechanical extraction using an expeller press under high temperature and pressure. Subsequently, solvent extraction is also used to extract more oil. The expelled oil is redirected to an oil refinery, while the residual de-oiled cake is processed so that all that protein can be used to make different products like animal feed.
Rapeseed or canola (Brassica napus). Known for its bioactive compounds and high unsaturated fatty acid content, which lend it a high nutritional value, rapeseed oil is the third most consumed cooking oil globally - its consumption is less than that of only palm oil and soyabean oil. As one of the most important seeds for oil extraction globally, mustard or rapeseed goes through two rounds of expeller pressing after it is cleaned and flaked. The residual cake after mechanical extraction is then showered with the solvent hexane for a final pass at oil extraction. All the extracted oil is then refined to get the purified variety that you might find in your kitchen.
Sunflower (Helianthus annuus). Extracted from the seeds of the sunflower plant, sunflower oil is rich in the essential fatty acid, linoleic acid. Some sunflower seeds are cultivated to be consumed as is, while some are cultivated for their oil. These seeds for oil extraction may also be grown to contain high amounts of oleic acid, which is used as a dietary source of polyunsaturated fat. When used as seeds for oil extraction, sunflower seeds are prepared using seed cleaning machines and dehullers. The prepared seeds and their kernels are subjected to expeller pressing i.e. mechanical extraction. After this, solvent extraction is the final round of oil extraction, after which all the extracted oil is redirected to an edible oil refining operation.
Groundnut (Arachis hypogaea). Boasting a high energy value, groundnuts - also called peanuts - are rich in oil and protein. While China, India, Nigeria, and the USA lead the world in groundnut production, other countries in Africa and South America also have substantial groundnut cultivation. As a cooking oil source and a protein source, groundnuts are high-quality agricultural raw materials. Good post-harvest handling is required to prevent peanut contamination by aflatoxins and to maintain the produce quality. While the seeds oil extraction machines used to extract groundnut oil aren't unique, the preparatory steps are slightly different from those for the other oilseeds we've discussed so far - decortication and oilseed conditioning are integral steps in preparing the seeds for oil extraction.
Palm kernel (Elaeis guineensis). Distinct from palm oil and coconut oil, both of which are extracted from the fruit of palm trees, palm kernel oil is extracted from the seed of the oil palm Elaeis guineensis. Palm kernel oil has about 82% saturated fat, because of which it is hard and brittle at room temperature. At body temperature, however, it melts quickly due to the presence of 48% lauric acid, which has a low melting point. This oil is commonly used to produce confectionary products. Like most other seeds for oil extraction, palm kernels, too, undergo a combination of mechanical extraction and solvent extraction, followed by filtration and refining, before we get a final product that can safely be used for culinary applications.
Due to their versatility and widespread cultivation, these are among the best seeds for oil extraction. Nonetheless, the value of these seeds extends far beyond their oil. From plant-based protein to feedstock for biodiesel production and oleochemical manufacturing, oilseeds have incomparable economic, social, and environmental value. Their cultivation and consumption promote employment across the value chain, help people meet their dietary needs, and help replace polluting or toxic substances with natural ones. Essentially, seeds for oil are also seeds for food, feed, and fuel, and symbols of a green and circular economy.
You might find these interesting:
Choosing the perfect oil extraction unit for your business
Discover how to make the most of oilseeds
Building a resilient supply chain in the oilseeds processing industry
