Determination of Neutral Lipids in Regular and Lowfat Eggs by High Performance TLC with Densitometry

Abstract

A simple quantitative HPTLC method was developed for determination of cholesterol esters, triacylglycerols, free fatty acids, and cholesterol in hens' egg yolk. Lipids were extracted with chloroform-methanol (2:1), the extract was passed through a glass wool column, and the eluate was chromatographed on laned preadsorbent silica gel HPTLC plates with bracketing standards using the Mangold developing solvent for the latter three lipid classes or a modified Mangold solvent for cholesterol esters. Lipids were detected with phosphomolybdic acid spray reagent, and zones were quantified by densitometric scanning. The method was used for the analysis of four regular and four lowfat eggs, and it was found that there was no significant difference between the two types of eggs except for a lower concentration of free fatty acids in the lowfat eggs. There was no significant difference between the mean cholesterol content of either type of eggs in this study and 18 regular eggs analyzed in 1987. Fractions containing monoacylglycerols, diacylglycerols, and nonpolar hydrocarbons were identified in yolk from both types of eggs, but amounts were not quantified.