1 EGG-YOLK LECITHIN FRACTIONATION AND CHARACTERIZATION 2

Abstract

2 Egg-yolk lecithin has phospholipid class and fatty acid compositions that are different 2 from soybean lecithin, and egg-yolk lecithin may have unique functional properties. The purposes of this research were to develop an effective method for extracting sufficient amount of 4 lecithin from fresh egg yolk, and to evaluate its functional properties. Ethanol was used to dehydrate and partially extract the phospholipids (PLs), followed by hexane to extract the total 6 lipids. A phase separation of the combined extracts resulted in neutral and polar lipid fractions. An acetone precipitation of PLs from the final polar lipid fraction was necessary to remove 8 residual neutral lipids, especially cholesterol. PL purity of the lecithin product was 95%. Surface tension reduction, emulsion stability and oxidative stability studies were conducted to 10 characterize functional properties of egg-yolk lecithin. Egg-yolk lecithin and soy lecithin had similar surface activity as evaluated by surface tension reduction in an aqueous system and the 12 critical micelle concentration (CMC). Soybean lecithin created a more stable emulsion than egg-yolk lecithin. However, egg-yolk lecithin was more oxidatively stable than soybean lecithin. 14