Preferential degradation of noncholine phosphatides in soybean lecithin by thermalization

• Published in: Journal of the American Oil Chemists' Society Vol. 71; no. 11; pp. 1195 - 1199
• Main Author: Weete, J.D. (Auburn University, Auburn, AL.)
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer‐Verlag 01-11-1994; Springer
• Subjects: ACEITE DE SOJA; Analytical, structural and metabolic biochemistry; Biological and medical sciences; CALENTAMIENTO; CHAUFFAGE; DECOMPOSITION; DEGRADACION; DEGRADATION; Diglycerides; Fat industries; Food industries; FOSFOLIPIDOS; Fundamental and applied biological sciences. Psychology; Glycerolipids, phospholipids; GLYCEROPHOSPHOLIPIDS; GOMAS; GOMME; gum; GUMS; HEATING; HUILE DE SOJA; lecithin; LECITHINE; LECITHINS; LECITINAS; Lipids; Other biological molecules; PHOSPHATIDE; phosphatidylcholine; PHOSPHATIDYLCHOLINES; PHOSPHOLIPIDS; SOJA; SOYBEAN OIL; SOYBEANS; thermalization; Lecithin; Diglyceride; Thermalization; Phosphatidylcholine; Phospholipid; Qualitative analysis; Soybean; Degradation product; Thermal degradation
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1007/BF02540536

Purified soybean lecithin and the gum derived from soybean oil processing were heated separately in bulk at 125 to 200°C for 60 min, or at 175°C for 30, 60, 90 and 120 min, and the products were analyzed by thin‐layer chromatography and high‐performance liquid chromatography. It was found that the noncholine phosphatides are preferentially degraded relative to phosphatidylcholine, and that these phosphatides are broken down in the order phosphatidyl‐ethanolamine (PE)>phosphatidylinositol (PI)>phosphatidic acid (PA) with increasing temperature. At 175°C, the heating time required to degrade the noncholine phosphatides was between 30 and 60 min. Diglycerides were the principal products of thermalization at 77% of the total material, indicating that the 3‐phosphoester linkage is the most heat‐labile portion of the noncholine phosphatide molecules. Cleavage of the fatty acids from positions 1 and 2 of the phosphatides was minimal, as indicated by the relatively low amount of free fatty acids (8% of the total) when the lecithin was heated at 180°C for 90 min. The appearance of brown discoloration, characteristic of heated lecithin, coincided mainly with the decomposition of PE.