MOISTURE-CONTENT AND PARTICLE-SIZE OF DEHYDRATED EGG-YOLK AFFECT LIPID AND CHOLESTEROL EXTRACTION USING SUPERCRITICAL CARBON-DIOXIDE

Egg yolk was spray-dried under conditions to produce a small particle size powder and a large particle size powder. Particle size was determ ined using a Nikon Optiophot microscope. Spray-dried egg yolk was also adjusted to various moisture levels as follows: control (2 to 4% mois ture), 7% moisture, and 12% moisture. Supercritical carbon dioxide ext raction (SCE) of each of these moisture treatments at 45 C/306 atm usi ng 30 g CO2/g of sample was completed. For the particle size study, 45 g CO2/g of sample at 45 C/306 atm was utilized. Particle size exhibit ed a significant effect on cholesterol and lipids extracted using SCE. As moisture content of dried egg yolk increased to 7%, there was a si gnificant increase in lipids extracted using supercritical carbon diox ide. Moisture content had no significant effect on cholesterol extract ion. After extracting SCE higher moisture spray-dried egg yolk, sponge cake volume was significantly reduced compared to that of the control . The reduced sponge cake volume may be due to protein denaturation.