Free fatty acids recovery

Solvent extraction in batch or continuous systems is used to recover most of the residual oil from the presscake. Heptane, hexane, or a mixture of these solvents is used to recover the oil. The solvent-extracted presscake is steam stripped to recover solvent and a residual meal known as castor pomace, containing 1% residual oil. The solvent extracted oil is also processed for solvent recovery (qv). The oil from the extraction procedure is darker than the mechanically pressed oil and has a higher free fatty acid content. It is sometimes referred to as a No. 3 castor oil and is used for blending with higher quaUty oils that are well above No. 1 specifications. 

Traditional column chromatography has also been employed for the extraction of carotenoids from palm oil. Separations were carried out on silica columns, carotenoids were eluted with n-hexane while the free fatty acids of the oil were removed from the stationary phase with ethyl acetate. The recovery of the method was 45 per cent and the purity of the cartotenoid fraction about 20 per cent w/w [23],... 

Alkali-catalyzed transesterifications have several drawbacks in addition to the problem of free fatty acids and water in the feedstock. They are energy intensive, recovery of the glycerol is difficult, the basic catalyst has to be removed from the product and the alkaline waste water requires treatment. These disadvantages could be circumvented by employing a lipase catalyst. But, in order to be economically viable, the enzyme costs have to be minimized through effective immobilization and recycling. 

Microwave treatment, because of its rapid heating of materials, is being explored in a multitude of crops for enzyme inactivation (25-28), for extraction of natural products (29), and oil and fat extraction from seeds and food products (30-32). Microwave treatment of peanut seed prior to press extraction increased oil recovery approximately 10% at an optimum treatment time of 30 seconds (30). However, free fatty acid content initially increased with exposure time as well as peroxide value (30). Research on use of microwave treatment in blanching of peanuts indicated an influence on oil stability depending on treatment conditions (33). 

The preparation of high-purity tocopherols and phytosterols involves steps such as molecular distillation, adduct formation, liquid-liquid extraction, supercritical fluid extraction, saponification, and chromatography (175). The extraction of tocopherols from soybean oil deodorizer distillate by urea inclusion and saponification of free fatty acids resulted in good recovery of tocopherols (208). To improve the separation of sterols and tocopherols, Shimada et al. (209) used a lipase to esterify sterols with free fatty acids. Then the steryl esters and tocopherols were separated better by molecular distillation. Chang et al. (210) used supercritical fluid CO2 extraction to recover tocopherols and sterols from soybean oil deodorizer distillate. A patent by Sumner et al. (211) advocated treatment of the distillate with methanol to converted free fatty acids and other fatty acid esters to methyl esters that can then be removed by a stripping operation. Then separation of sterols and tocopherols could be carried out by molecular distillation. 

SCCO2 fractional extraction of soybean deodorizer distillate using an extractor with a reboiler at the bottom and obtained 83.6% tocopherol recovery at the optimal conditions of 31.03 MPa, 363 K top, and 343 K bottom temperature. Free fatty acids and squalene were concentrated in the extract together with tocopherols, whereas sterols were concentrated in the raffinate. 

The commercial membrane separation processes are offered in the areas of nitrogen production and waste treatment applications (1). Developing membrane applications in oil milling and edible oil processing are (1) solvent recovery, (2) degumming, (3) free fatty acid removal, (4) catalyst recovery, (5) recovery of wash water from second centrifuge, (6) coohng tower water recovery, (7) protein purification, and (8) tocopherol separation. 

Freeze-drying is also highly useful as a preconcentration method. For example, using it to concentrate the sodium salts of free fatty acids in cheese following extraction with ether substantially improves the recovery of volatile acids in general and acetic acid in particular [59]. 

Tall oil, derived from the Swedish tallolja meaning pine oil, is recovered from the black liquor of softwood pulping. It is taken out at an intermediate stage of the multiple-effect evaporation when the liquor contains about 30% total solids, after it is allowed to stand [21]. The soaps (sodium salts of fatty acids present) are insoluble, cream to the top of the vessel, and are skimmed off. The residual black liquor is returned to the evaporators to continue chemical recovery. The soap yield, which can range from 10 to 200 kg/tonne of pulp (or even higher for pine), is then acidified and the free fatty acids and resin acids obtained are separated by distillation. The fatty acids recovered consist mainly of oleic and linoleic acids and are employed in soap manufacture and as the drying oil components of paints and varnishes [22] (Chap. 19). Resin acids consist of terpene acids such as abietic acid and its positional and reductive variants, and are mainly employed in paper sizing. 

Extraction of free fatty acids from naturally occurring glycerides removal of HCl from chlorinated organic compounds recovery of aliphatic acids HE and HCl from aqueous solutions nitration of phenol solvent extraction in mineral processing interfacial polycondensation and esterification manufacture of organo-phosphate pesticides. 

Oorrparing the results of Krutonis and Daniels et al. ows that vhen the starting material was free fatty acids, the recovery of EPA was similar but low. For EHA, the recovery reported by Krukonis was very low, around 19%, and significantly different from that of Daniels et al. at 92.4%. Oanoparison of the results of Krukonis to those of Eiseribadh (16) for the fractionation of methyl esters indicates that both EPA and EHA show very similar concentrations (Table IV). From Table IV it is apparent that SFE of fish oil enhances EPA and EHA concentrations and that fatty acids are more efficiently separated as their methyl esters. 

OFig. 3. Recovery of radioactivity in phospholipid (A), free fatty acid (B), free cholesterol (C), and cholesteryl ester (D) fractions for the first three intervals in the thoracic duct lymph in rats infused with emulsions containing " C-labeled 1,3-dioleoylglycerol (DAG) or trioleoylglycerol (TAG). Each value represents the mean SEM, n = 7. Significantly different (P< 0.001) from the corresponding values for the rats infused with C-labeled trioleoylglycerol. 

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