Extraction, oilseed

Many solvents have been proposed for extracting oilseeds, but later found ineffective others were used for a period, but disallowed because of health concerns about residues in food and feed products, or worker exposure.93 All Extraction solvents approved... 

Galvin, J. B., Toxicity data for commercial hexane and hexane isomers, in Technology and Solvents for Extracting Oilseeds and Nonpetroleum Oils, P. J. Wan and P. J. Wakelyn (Eds ), pp. 75-85, AOCS, Champaign, IL, 1997. 

Mechanically Extracted Meals. Solvent extracted oilseed meals typically contain less than 1.5% residual fat unless the gums (hydrated phosphatides) or soapstock have been added back to the meal before the desolventizer-toaster or meal dryer. Mechanically extracted (expeller or screw-pressed) meals can contain 4—9% oil, which can be a significant calorie source in animal feeds. Fat contents of extracted meals are not part of the definition, although typical analyses are shown below. 

The major lecithin sold domestically in commercial quantities is extracted from soybeans. Com and sunflower seed lecithins are available in limited amounts. Canola is being reviewed as a lecithin source in countries that do not grow significant quantities of soybeans. Lecithins may be added to feeds in cmde or refined forms, remain as residuals in solvent- or mechanical-extracted oilseed meals, be returned to oilseed meals as extracted gums or soapstocks at combined solvent extraction-oil refinery operations, or simply be native to an oilseed fed whole. 

King JW. Critical fluids for oil extraction. In Wan PJ, Wakelyn PJ, eds. Technology and Solvents for Extracting Oilseeds and Non-petroleum Oils. Champaign, IL AOCS Press, 1997 283-310. 

Most lecithins obtained during degumming of edible oils are not suitable for human consumption. Therefore, they are added back to the extracted oilseed meal and used as feed. Only soybean lecithin is snitable for human and industrial uses. Properties required for soybean lecithin are shown in Table 5.4 (adapted after Precise, 1985). The phospholipid fraction of soybean lecithin contains about 30 to 32% phosphatidylcholine, 22 to 28% phosphatidylethanolamine, 18 to 20% phosphatidyUnositol, 3 to 4% phosphatidylserine, and 20 to 29% other snbstances. The fatty acid composition of soybean lecithin is shown in Table 5.5. The technical soybean lecithin obtained by extraction with a hydrocarbon solvent is very different from the phospholipid fraction obtained by extraction with chloroform-methanol (after Folch). 

This chapter presents information on solvents for extracting oilseeds and other biological materials for oils, fats, and other materials. 

J.B. Galvin, Toxicity Data for Extraction Solvents Other Than Isohexane/Hexane Isomers, in Technoiogy and Soivents for Extracting Oilseeds and Nonpetrolenm oils, PJ.Wan and PJ.Wakelyn, Eds., AOCSPress, Champaign, IL, 1997, p. 75-85. 

Folic acid is widely distributed in nature green leafy materials, cereals and extracted oilseed meals are good sources of the vitamin. Folic acid is reasonably stable in foods stored under dry conditions, but it is readily degraded by moistine, particularly at high temperatures. It is also destroyed by ultraviolet light. 

Many solvents have been proposed or used for extracting oilseeds, but later have been found ineffective in extracting oil or have been disallowed because of health concerns about residues in food and feed products and exposure of employees. Essentially all commercial oil extraction now is done with hexane, a petroleum refinery fraction with a boiling point of 65 to 68°C (149-155°F) that consists of 48 to 98 percent n-hexane with the balance being short-chain homologs and branched compounds. Currently, ethyl and isopropyl alcohol are attracting the most attention as alternative extraction solvents. 

P.J. Wan, Hydrocarbon Solvents, in Technology and Solvents for Extracting Oilseeds and... 

---