Common Oilseed Extraction Processes & Equipment

oilseedsOil can be extracted from a large variety of oil bearing seeds and nuts for both human and animal consumption as well as for a range of industrial uses from biofuels to consumer products.  The following outlines the most commonly processed oilseeds, the use of their oils and the common extraction processes and necessary equipment.

Soybean

Soybean, also referred to a soy or soya, is a legume.

About 85% of the world’s soybeans are processed, or crushed, annually into soybean meal and vegetable oil.  Approximately 98% of the soybean meal that is crushed is further processed into animal feed with the balance used to make soy flour and proteins. Of the oil extracted, 95% is consumed as edible oil; the rest is used for industrial products such as fatty acids, cosmetics, soaps and biodiesel.   In addition, soybeans are processed into hydraulic oil, grease, solvent, ink, plastics and other products.

After being cleaned and dehulled, one of three processes is used to separate the soybean oil from the protein meal are: solvent extraction, continuous pressing or hydraulic pressing.

  • Continuous pressing: This process is performed at elevated temperatures, using an oil extraction screw press to express the oil from ground and properly conditioned soybeans. The pressed cake is reduced to between 4-6% oil content by this method.
  • Solvent extraction: This process, which is the one used most commonly around the world, uses hexane to extract the oil from flaked soy. This method reduces the level of oil in the extracted flakes to 1% or less.
  • Hydraulic pressing: This is an intermittent pressing operation carried out at elevated temperatures in a mechanical or hydraulic press after the soybeans have been rolled into flakes and properly conditioned by heat treatment. It is the oldest known method of processing oilseeds.

The world’s top producers of soy are the United States, Brazil, Argentina, China and India.   In 1996, French installed the world’s largest soybean extractor in Argentina.  The U.S. produces roughly 75 million metric tons of soybeans each year, exporting large quantities of soybeans, as well as meal and oil, to Europe and Asia.

Contact French engineers for more information regarding oilseed extraction equipment.

Canola/rapeseed

Canola is a variety of rapeseed that was developed in the early 1970s by Canadian scientists using traditional plant breeding techniques to remove the anti-nutritional components from rapeseed to assure its safety for human and animal consumption.  To be defined as canola, the seed must have less than 2% erucic acid and less than 30 umoles glucosinolates.

Canada is the biggest single producer of canola, producing 20% of the world’s canola/rapeseed . However, the EU member countries combined grow more canola and China’s rapeseed acreage exceeds Canada’s canola production.  The U.S. is Canada’s largest canola buyer.

Canola seeds contain 40-43% oil and are crushed to obtain the oil, the main product of the canola seed. The remainder of the seed is processed into meal, used as a high protein livestock feed or to produce biodiesel.

The first stage in processing canola is to roll or flake the seed in a roller mill or flaking mill. This ruptures cells and makes the oil easier to extract.  Next the flaked or rolled seeds are put into a conditioner/cooker and subjected to a mild pressing process which removes some of the oil and compresses the seeds into large chunks called “cake fragments.”  The cake fragments undergo further processing in a screw press to remove most of the remaining oil. The oil extracted during each step is combined and then subjected to processing according to the end product requirements.

Contact French for more information about our conditioner press for flaked or rolled seeds.

Cottonseed

Cottonseed is the seed of the cotton plant, separated from the fiber of the cotton ball. About 30% of cottonseed produced from the crop is used to produce edible oil, animal feed ingredients and ingredients for other industrial and consumer products.  Cottonseed oil is extracted using either a solvent extraction method or the full press method to produce high quality clarified crude oil and low-fat press cake.  Some possessors cycle the seeds through a flaking mill, like the French 2452 model with chilled cast iron rolls, to change the tissue structure of the oilseed cells while pressing them into flakes of different thickness to press out the oil.

Prior to the introduction of the screw press into the Oilseed industry, processors pressed oil from the seed using hydraulic presses.  In 1908, French marketed a 24,000 pound cottonseed hydraulic press, made from steel instead of cast-iron, a major innovation at the time.

The world’s top cottonseed producers are China, India, the United States and Pakistan.

Contact French for more information about our 2452 flaking mills.

Sunflower

The sunflower is a distinctive, flowering plant, Helianthus annuus L., with seeds containing a valuable edible oil, rich with Vitamin E. Most sunflower oil is used in food products though it is also used in the cosmetic market.  Confection sunflower seeds are also sold for human consumption and birdseed.

The sunflower industry continues to have adequate processing capacity to meet the demands of the domestic and international markets. The U.S. is recognized as having the highest quality of sunflower products due to technology that currently surpasses any other supplier.

Sunflower oil can be extracted during the solvent extraction process using chemical solvents or by a screw press used to squeeze the oil directly from sunflower seeds by crushing them.  This method of cold-pressing sunflower seed oil under low-temperature conditions is a preferred method for those seeking an extraction process that doesn’t involve hexane.

Contact French for more information about our solvent extraction technologies.

Peanuts

Peanuts, or “groundnuts” are the edible seeds of a legume, Arachis hypogaea, and they are high in protein, oil and fiber.

The United States is the third largest producer of peanuts, trailing China and India, but is one of the world’s leading exporters.  Peanuts produced in the U.S. are mostly used in food and confection products, but more than 50 percent of the worldwide production is crushed for its oil. Peanut oil is often used for cooking, due to its mild flavor and relatively high smoke point.

The oil is extracted from shelled and crushed peanuts by one or a combination of the following methods: screw pressing, hydraulic pressing and/or solvent extraction.

Corn germ

Corn, Zea mays L., is a cereal crop, a member of the grass family. Corn is grown throughout the world and is one of the globe’s most widely used food staples.  Corn varieties are directly used for food and animal feed or processed to make food and feed ingredients or industrial products such as ethanol and polylactic acid (PLA).  The two primary methods of processing corn are referred to as dry and wet milling.

The oil extracted from corn germ has high polyunsaturated fatty acid content and oxidative stability. Its largest single use is in bottled oil for consumer use, followed by margarine and industrial snack-frying operations.

The US is the world’s largest producer of corn, with 80 million acres of land dedicated to cultivating corn, larger than the landmass of Germany.  Over half of the U.S. corn crop is used for feed. The remaining U.S. crop is split between exports (20%) and food, seed or industrial uses such as ethanol production.  Other major corn producing countries include China, Brazil, Mexico and the European Union.

Algae

Algae is an informal term for a large, diverse group of eukaryotic organisms that are not necessarily closely related.  Commercial and industrial algae cultivation has numerous uses, including production of food ingredients such as omega-3 fatty acids or natural food colorants and dyes, food,fertilizer, bioplastics, chemical feedstock (raw material), pharmaceuticals, and algal fuel, and can also be used as a means of pollution control.

While algae is naturally occurring, many companies cultivate algae using either autrophic growth or hetertrophic methods and then harvest the algae for biofuel or other industrial uses.

The simplest method to extract the oil from algae is mechanical crushing. When algae is dried it retains its oil content, which then can be pressed or extracted out with an oil press. Different strains of algae warrant different methods of oil pressing, including the use of screw press. Many commercial manufacturers of vegetable oil use an oil extraction combination of mechanical pressing and chemical solvents.

Additional oil bearing seeds

Mustard, flaxseed, linseed, safflower, jatropha, grape seed, morinda seed, marigold, paprika seed, walnut meats, hemp seed, cuphea seed, lesquerella seed, vernonia seed, corn germ foots, bagasse, apricot kernels, coffee beans, chili peppers, cherry pits, peach pits, potato chips

For more information on oilseeds visit SoyaTech.