Squeezing Fat Out of Foods

By Dawn Johnson
August 27, 1997

It sounds like a dieter’s dream: finding a way to squeeze the fat out of foods we love, like big juicy hamburgers.

Scientists with USDA’s Agricultural Research Service have developed a way to do just that--not for the sake of counting calories, but for food analysis--while reducing the steps and chemical solvents now used to analyze foods’ fat content for nutritional labeling.

By teaming a technology called supercritical fluid extraction with an enzyme called lipase, the scientists can simultaneously extract fat from hamburger samples and complete the chemical reaction needed to release the fats. In conventional fat analysis, the sample must first be treated with chemical solvent to break down the bonds in the meat which hold the fat molecules in place. Then more chemicals are required to actually extract the fat.

Supercritical fluids are highly compressed gases, such as carbon dioxide, with densities that resemble those of liquids. In an extraction chamber, the fluid flows through a sample and dissolves specific chemicals, or fats in the case of food extractions. The gas is then decompressed and harmlessly vented into the atmosphere, leaving the extracted fats behind.