April 15/Journal of Technology & Science -- "Egg yolk is an excellent source of phospholipids. Egg yolk powder (EYP) contains about 60% lipids, which consist of, on average, neutral lipids (65%), phospholipids (31%) and cholesterol (4%)," scientists in Turku, Finland, report.

"The utilization of supercritical fluid techniques is a new way to selectively extract and fractionate non-polar and slightly polar components from foods and food products. In this study, we developed pilot-scale production methods for the isolation of high-purity egg yolk phospholipids. The method involves either liquid ethanol or supercritical fluid extraction (SFE) as isolation method and supercritical antisolvent process as precipitation method. EYP was fractionated to lipid- and protein-rich fractions using liquid ethanol or supercritical fluid as an extraction medium. In both cases, the target fraction was phospholipids dissolved in ethanol. From this solution, phospholipids were precipitated using supercritical carbon dioxide as antisolvent. Depending on the process conditions, 72-99% of the precipitate consisted of phosphatidyl choline and phosphatidyl ethanolamine, which appeared in ratios 6:1-7:1," wrote H. Aro and colleagues.

The researchers concluded, "The highest purity of phospholipids was obtained via precipitation of the isolate obtained using two-step SFE."

Aro and colleagues published their study in European Food Research and Technology ("Isolation and purification of egg yolk phospholipids using liquid extraction and pilot-scale supercritical fluid techniques." European Food Research and Technology, 2009;228(6):857-863).

For more information, contact H. Aro, TE Center SW Finland, Employment & Economics Development Center, Ratapihank 36, Turku 20100, Finland.

From the April 27, 2009, Prepared Foods E-dition