Folch extraction

Introduction:

Because fats are often associated with other molecules (lipoproteins, liposaccharides), or cell membranes, simple shaking the sample with a water immiscible solvent will not lead to efficient extraction.

Method

The Folch extraction exposes the food to chloroform and methanol (2:1) in the presence of water. Methanol is used to access the food matrix and release the fats from the proteins and carbohydrates. The released fats dissolve into chloroform. Water is necessary to separate chloroform and methanol. A final purification step with chloroform is required to remove non-fat material. After that, the chloroform fraction is isolated, evaporated, and the residue (total fat) is weighed.

Characteristics

• Applicable for all types of foods.

• Preferred method when further characterisation of lipid classes or fatty acid profile is required.

• Extraction of both polar (e.g. structural fat such as phospholipids) and non-polar lipids (e.g. storage fat such as triglycerides).

• Incomplete extraction of fat in baked (cereal) products.