Most people think that cutting down on cholesterol means removing eggs from the refrigerator - forever.
Oscar A. Pike, a Brigham Young University assistant professor of food science and nutrition, believes the much-maligned egg shouldn't be dismissed so easily.Cholesterol-free egg oil is one potential new food product, he said.
"Eggs are not being fully utilized because of their cholesterol content, which actually makes up only 5 percent of an egg yolk," said Pike.
Separating the various lipids or oils from an egg yolk, isolating and removing the cholesterol and then recombining the remaining lipids has been the focus of recent research by Pike and graduate student J. Blackwelder.
Results of their research on the stability of cholesterol-free egg lipids were presented at the 49th Annual Meeting of the Institute of Food Technologists.
To extract the cholesterol, food-grade solvents were used to separate the lipids from the yolk, which essentially is composed of water, proteins, lipids and cholesterol. Lipids and proteins are what give an egg its flavor.
Once the lipids were isolated, cholesterol was captured by filtering the liquid through a thin glass column containing silicic acid.
Two lipid fractions, triacylglycerol and phospholipid, were completely cholesterol-free, Pike found.
The researchers then recombined those two lipid fractions to produce a cholesterol-free egg oil.
"This oil could be used for cooking where you want an egg flavor but don't want the cholesterol," said Pike. "And we know there's very little residual odor left in this oil, which is extremely important."
Soybean and other salad oils are produced in this same manner, by utilizing food-grade solvents that are usually alcohol-based.
One unique aspect of this oil is that the two recombined lipids show a much higher stability than the individual fractions, he said. That is important because it protects oil from going rancid.
While it's wise to work at lowering one's blood or serum cholesterol level, Pike said, people should consider the difference between cholesterol found in an egg and that found in other foods that have significantly higher levels of saturated fats.
New research indicates the average egg yolk contains nearly 210 milligrams of cholesterol (lower than the previous count of 274 mg), which is just 90 mg short of the 300 mg-per-day limit that the American Heart Association suggests as a dietary benchmark.
Watching the level of cholesterol in your blood - not just your diet - means cutting out saturated fats, something that eggs have very little of, said Pike.
"More and more research shows that dietary cholesterol has not nearly as much to do with heart disease as saturated fat does," he said. "Saturated fat affects blood cholesterol levels. The biggest misconception, in my opinion, is that people don't make a distinction between dietary cholesterol and blood cholesterol levels."
While two eggs provide about three grams of saturated fat, 3.5 ounces of broiled sirloin steak (a fairly average portion) rack up 7 grams of saturated fat.
"To tell someone to simply cut eggs out from their diet to reduce cholesterol levels is an oversimplification," Pike said. "By pinning it on eggs alone, the average person isn't getting enough cholesterol out of the diet in order to effect a change in blood cholesterol levels. You have to consider everything you eat and the amount of saturated fat it contains."