Phosphatide purification

We have used both the commercial crude and stripped materials without further purification in tests of relative antioxidant effectiveness because they effectively simulate two different food exposures of phosphatide. The crude material simulates a typical emulsified oil (35% triglyceride), as in a baking shortening, while the stripped powder in microdispersion (3-5% triglyceride) is an approximate membrane model (25). 

Refining involves the purification of triglyceride to remove impurities (phosphatides, polyethylene, chlorophyll, heavy metals, off-odors, color bodies) by a combination of acid/alkali washing, clay/activated silica bleaching, deodorization, and hydrogenation steps. 

Soy lecithin is a coproduct of oil processing. As a result, purification steps used to produce quality oil may affect the lecithin components. Also, soybeans exposed to frost damage, or subjected to prolonged storage, have reduced lecithin yields (33). Phospholipases, which produce phosphatidic acid, are active during storage and may reduce the yield of lecithin (34). During the maturation process, the major phospholipids (PC, PE, and PI) increase, and others decrease or remain constant (32). 

In conventional chemical processing of vegetable oils, crude oil is recovered from the mechanically expressed vegetable seed by solvent extraction using hexane, as shown in Figure 3.14 [22]. The misceUa (a mixture of extracted oil and solvent) from the extractor contains 60—70% solvent, which is recovered by distillation and reused. Purification of crude oil consists of removing components that are harmful and are not wanted in the final product, the pure oil. These components are phosphatides (gums and lecithin). 

Kanamoto et al., (1981) reported that the degrees of hydration of phosphatidylethanolamine and phosphatidic acid are increased in the presence of phosphatidylcholine due to the formation of mixed micelles. This association forms the basis of a method of oil purification by the addition to an oil of hydratable phosphatides. The method is the subject of United States Patent No. 4 162 260. 

THE PURIFICATION AND CHARACTERISATION OF PHOSPHATIDATE PHOSPHATASE FROM AVOCADO... 

Lin, Y-P. and Carman, G.M. (1989) Purification and characterisation of phosphatidate phosphatase from Saccharomyces cerevisiae, Journal of Biological Chemistry 264, 8641-8645... 

Fleming, I.N. and Yeaman S.J. (1995) Purification and characterisation of iV-ethylmaleimide-insensitive phosphatidic acid phosphohydrolase (PAP2) from rat hver. Biochemical Journal 308,983-989... 

Ohta, H, Shimojima, M, Aral. T., Masuda, T., Shioi, Y., Takamiya, K. UDP-galactose diacylglycerol galacto.syltransferase in cucumber seedlings Purification of the enzyme and" the actix ation by phosphatidic acid. Phinl Lipid MelahoUsw (eds by Kader, J.-C and Mazliak, P.) 1995 152-155. 

The Purification and Characterisation of Phosphatidate Phosphatase from Avocado. M. Pearce and A.R. Slabas. 

The free acids are soluble in ether and ethanol the sodium salt is soluble in ether but insoluble in ethanol (Kates 1955). Phosphatidic acids can be prepared enzymatically by the action of phospholipase D on phosphatidyl chofine (Hanahan 1957) with Uberation of the nitrogen base. Phosphatidic acids with two identical acyl components have been prepared synthetically (Baer 1951 Baer et al. 1958). Isolation and purification may be accomplished using silicic acid or anion-exchange resins (Kornberg et al. 1953). Nothing is known about the stabihty under the conditions of the chromatographic procedures. 

UDP-GALACTOSE DIACYLGLYCEROL GALACTOSYLTRANSFERASE IN CUCUMBER SEEDLINGS PURIFICATION OF THE ENZYME AND THE ACTIVATION BY PHOSPHATIDIC ACID... 

Thomson FJ, Clark MA. Purification of a phosphatidic acid hydrolyzing phospholipase A2 from rat brain. Biochem J 1995 306 305-309. 

After administration of labeled phosphate, free phosphate and also some of the acid-soluble fractions of organs are often much more active than the phosphatide fraction. It is therefore of great importance to purify the phosphatides and free them from all other active fractions. Levene s classical method, which is based on the extraction of the mineral constituents by shaking an ether solution of phosphatides with a water solution of acetic acid, does not remove the labeled free phosphate. When, however, acetic acid is replaced by hydrochloric acid, an effective separation can be obtained (69). The effectiveness of this method of purification is seen from the figures of Table XII (9). 

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