Edible Oils Extraction

The other cleanup method utilizes the adsorptive properties of activated carbon to remove caffeine from the carbon dioxide before recycle (Zosel, 1981). An adsorption isotherm of the carbon dioxide-caffeine-activated carbon system, shown in figure 10.3, indicates that it is possible to adsorb the caffeine in the carbon dioxide-rich stream onto activated carbon (Krukonis, 1983a). In this industrial application an activated carbon bed is used to remove a component from a supercritical carbon dioxide-rich stream rather than having the activated carbon regenerated by the supercritical carbon dioxide. It is perhaps no surprise that spent activated carbon is difficult to regenerate with carbon dioxide, as discussed in chapter 8. 

The process development work being carried out at the United States Department of Agriculture s (USDA) Northern Regional Research Center on 

Carbon dioxide has been tested with other materials, such as corn and wheat germ, sunflower and safflower seeds, and peanuts. To a very good first approximation, the solubility of all vegetable triglycerides is identical, and all these seeds can be extracted completely if the cells are macerated to make the oil accessible. 

Recently, a supercritical carbon dioxide process has been proposed to concentrate certain aromatic constituents in lemon oils, specifically the oxygenated components from limonene (Robey and Sunder, 1984). Although the components can be concentrated by either steam distillation or liquid-liquid extraction, these processes suffer from drawbacks, such as product degradation, low yields, or the requirement of subsequent removal of solvent. The supercritical carbon dioxide process being developed operates at 60°C this precludes degradation of the sensitive essential oils. The extraction and 

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Hexane spilled onto surface soils will also volatilize to the air. Data sources were not identified allowing comprehensive quantitative estimates of the amount of -hexanc released on an annual basis to the air. In addition to releases from such commercial applications as edible oil extraction, the other major sources of atmospheric releases would be from emissions related to the -hexane contained in heating and motor fuels. 

Rosenthal, A, D.L. Pyle K. Niranjan. Aqueous and enzymatic processes for edible oil extraction, Enz. Microb. Technol. 1996, 19, 402—420. 

Geng, A., Lin, H. T., and Tan, Y. (2002) Solvent recovery from edible oil extract using nano-filtration ceramic membranes. In World Conference and Exhibition on Oilseed and Edible, Industrial, and Specialty Oils (p. 17) abstracts. Istanbul, Turkey. 

Rosenthal, A., Pyle, D. L., Niranjan, K., (1996), Aqueous and enzymatic process for edible oil extraction. Enzyme Microb. Tech. 19,402-420. 

Rosenthal A, Pyle DL, Niranjan K. 1996. Aqueous and Enzymatic Processes for Edible Oil Extraction. Enzyme Microb. Technol. 19 402-420. 

Solvent Extraction. Extraction processes, used for separating one substance from another, are commonly employed in the pharmaceutical and food processing industries. Oilseed extraction is the most widely used extraction process on the basis of tons processed. Extraction-grade hexane is the solvent used to extract soybeans, cottonseed, com, peanuts, and other oilseeds to produce edible oils and meal used for animal feed supplements. Tight specifications require a narrow distillation range to minimize solvent losses as well as an extremely low benzene content. The specification also has a composition requirement, which is very unusual for a hydrocarbon, where the different components of the solvent must be present within certain ranges (see Exthaction). 

Residuum oil supercritical extraction-petroleum deasphalting Polymer fractionation Edible oils fractionation Analytical SGF extraction and chromatography Reactive separations... 

Lipid-soluble food grade copper chlorophyll is manufactured similarly by extraction of adequate plant material, followed by replacement of magnesium by copper, and purihcation steps to remove carotenoids, waxes, sterols, oils, and other minor components that are co-extracted. Commercial copper chlorophylls may vary physically, ranging from viscous resins to fluid dilutions in edible oils as well as granulated forms and emulsions standardized with edible vegetable oil. Colors may vary... 

Residuum oil supercritical extraction (ROSE) (petroleum deasphalting) Polymer and edible oils fractionation CO2 enhanced oil recovery Analytical SCF extraction and chromatography Infusion of materials into polymers (dyes, pharmaceuticals)... 

Watts JO, Holswade W. 1967. Gas chromatographic determination of residual hydrocarbon solvents in solvent-extracted edible oils. J AOAC 50(3) 718-726. 

The contactor finds extensive use where high performance phase separation and countercurrent extraction or washing in the one unit are required. Particularly important applications are the removal of acid sludges from hydrocarbons, shown in Figure 13.40, hydrogen peroxide extraction, sulphonate soap and antibiotics extraction, the extraction of rare earths such as uranium and vanadium from leach liquors, and the washing of refined edible oils. 

A correlation may be established between the concentration of oxidized lipids and the TEARS value, expressed as MDA equivalents, in uM units. Correction is due in some cases for the interference by dyes or other factors. For example, the presence of anthocyanins in red cabbage leaves or turbiditjf causes overestimation of lipid hydroperoxides in plant tissue by the TEARS method. TEARS was used to assert the level of endogenous peroxides in hypo- and hyperthyroidism, both conditions being characterized by low lipid and lipoprotein plasma levels and enhanced oxidative metabolism . In a procedure for determination of TEARS in edible oils, the sample is placed in a centrifuge at 12000 g before measuring at 532 nm (e = 1.56 x 10 M cm ) . A usual procedure for determination of TEARS in certain complex matrices involves steam distillation of the aldehydes responsible for the value, instead of extraction. In nitrite-cured meats, excess nitrite may cause nitrosation of MDA, thus interfering with distillation. To avoid this interference sulfanilamide is added, which is converted to a diazonium salt and... 

The supercritical fluid extraction of oil seeds has been investigated extensively by several authors [34,98]. Possible applications of supercritical fluids in the edible-oil industry include deacidification, deodorization, and fractionation of crude oils and chemical conversion (like hydrogenation, and enzymatic reactions). 

Procedures for isolation and measurement of lipids in foods include exhaustive Soxhlet extraction with hexane or petroleum ether (AOAC, 1995 see Basic Protocol 1), chloro-form/methanol (Hanson and Olley, 1963 Ambrose, 1969), chloroform/methanol/water (Folch et al., 1957 Bligh and Dyer, 1959 see Basic Protocol 2 and Alternate Protocol 2), acid digestion followed by extraction (see Basic Protocol 4), or, for starchy material, extraction with n-propanol-water (e.g., Vasanthan and Hoover, 1992 see Basic Protocol 3). Each method has its own advantages and disadvantages and successful measurement of lipid content is often dictated by the type of sample and extraction medium employed. Commercial extraction and preparation of edible oils are explained in the literature (Williams, 1997). 

Toivo, J., Piironen, V., Kalo, P., and Varo, P. 1998. Gas chromatographic determination of major sterols in edible oils and fats using solid-phase extraction in sample preparation. Chroma-tographia 48 745-750. 

A capillary gas chromatographic method is described for determination of major phytosterols and cholesterol in edible oils and fats. To extract the unsaponifiable matter and for sample cleanup, solid-phase extraction with C18 absorbent was used. 

Edible oils are easily dissolved in benzene, but if a solid food is to be analyzed, the sample should be well ground first. A portion is accurately weighed, to which a known volume of benzene is added. The sample is mixed, centrifuged, and a 5.0-ml aliquot of this extract is used for the analysis. 

Various protocols and modifications have been reported in the literature on how to perform the TBA test. In foodstuffs, malonalde-hyde can be bound to various constituents of the food (e.g., proteins), and therefore it must somehow be released prior to determination. It is difficult to determine the optimal conditions for release of malonaldehyde as they differ from one material to another and require different conditions for hydrolysis. Heat and/or strong acid are thought to be essential for the liberation of malonaldehyde from precursors or bound forms, for condensation with TBA, and for maximal color development. For edible oil samples or lipid extracts, the test is simplified in that samples are directly dissolved in butanol and then an aliquot is reacted with TBA. Alternatively, a food sample can be heated with TBA solution and the red pigment that is formed can be extracted from the reaction mixture with butanol or a butanol/pyridine solution (Turner etal., 1954 Sinnhuberand Yu, 1958 Placer et al., 1966 Uchiyama and Mihara, 1978 Ohk-awa et al., 1979 Pokorny and Dieffenbacher, 1989). 

Blend samples with appropriate solvent and added dihydrophylloquinone (internal standard). Centrifuge. Evaporate sample extracts to dryness (except edible oils) and dissolve residue in hexane. Add equal volume of MeOH/HjO (9 1), mix, and centrifuge. Remove upper hexane layer and evaporate to dryness. 

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