Phospholipids, soybean, analysis

SL Melton. Analysis of soybean lecithins and beef phospholipids by HPLC with an evaporative light scattering detector. J Am Oil Chem Soc 69 784-788, 1992. 

SL Abidi, TL Mounts, T Finn. A preferred solvent system for high performance liquid chromatographic analysis of soybean phospholipids with evaporative light scattering detection. J Am Oil Chem Soc 73 535-536, 1996. 

For quantitation of cholesterol and its derivatives in muscle and liver tissues, the extracts of the tissue homogenates are evaporated, dissolved in a mobile phase such as hexane-isopropanol, and injected onto a normal-phase column. For analysis of soybean oil by reversed-phase HPLC, after extraction with chloroform-methanol (9 1), the neutral lipids, chlorophyls, and the phospholipids are separated by TLC. The lipids recovered from the TLC are analyzed by HPLC. 

Sotirhos, N., Ho, C.-T., Chang, S.S. High performance liquid chromatographic analysis of soybean phospholipids. Fette Setfen Anstrichm. 88,6 (1986)... 

Sotirhos, N., C. T. Ho, S. S. Chang, Normal and reverse phase HPLC analysis of soybean phospholipids, Dev. Food ScL, 1986, /2( Shelf Life of Foods and Beverages ), 601-608. 

The phosphoric acid esters of diacyl glycerides, phospholipids, are important constituents of cellular membranes. Lecithins (phosphatidyl cholines) from egg white or soybeans are often added to foods as emulsifying agents or to modify flow characteristics and viscosity. Phospholipids have very low vapor pressures and decompose at elevated temperatures. The strategy for analysis involves preliminary isolation of the class, for example by TLC, followed by enzymatic hydrolysis, derivatization of the hydrolysis products, and then GC of the volatile derivatives. A number of phospholipases are known which are highly specific for particular positions on phospholipids. Phospholipase A2, usually isolated from snake venom, selectively hydrolyzes the 2-acyl ester linkage. The positions of attack for phospholipases A, C, and D are summarized on Figure 9.7 (24). Appropriate use of phospholipases followed by GC can thus be used to determine the composition of phospholipids. 

Brash, A.R., Ingram, C.D., and Harris, T.M. 1987. Analysis of a specific oxygenation reaction of soybean lipoxygenase-1 with fatty acids esterified in phospholipids. Biochemistry 26 5465-5471. 

TL Mounts, AM Nash. HPLC analysis of phospholipids in crude oil for evaluation of soybean deterioration. J Am Oil Chem Soc 67 757-760, 1990. 

Lecithins as antioxidants. The literature is replete with references to the antioxidant properties of lecithins. For example, Pokomy (102) claimed that the addition of soybean phospholipids reduced the rate of autoxidation of sunflower oil and prolonged the induction period. Hudson and Ghavani (103) published data showing that the addition of 0.3% dipalmitoyl phosphatidylethanolamine (DPE) to refined soybean oil increased the induction time during Rancimat analysis from 8.8 hours to 19.3 hours. Hildebrand et al. (104), and Jung et al. (105), also published data demonstrating the antioxidant properties of various phospholipids and commercial lecithins. 

Rivnay, B., Combined analysis of phospholipids by HPLC and TLC. Analysis of phospholipid classes in commercial soybean lecithin,/. Chromatogr., 1984,294, 303-315. 

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