FAMEs by Degree of Unsaturation

Saturated, monounsaturated, polyunsaturated, and cis/trans configuration all refer to the structure of fatty acid moieties. Each group is believed to have the following effects on human health:
  • Saturated fatty acids (no double bonds) raise LDL cholesterol (increases risk of cardiovascular disease).
  • Mono- and poly-unsaturated cis fatty acids (≥1 cis double bond) lower LDL cholesterol (reduces risk of cardiovascular disease).
  • Mono- and poly-unsaturated trans fatty acids (≥1 trans double bond) raise LDL cholesterol (increases risk of cardiovascular disease) and also lower HDL (increases risk of type II diabetes).

Because of this, it is important for food manufacturers to measure and report their levels so consumers have the chance to establish healthy dietary strategies. Nutritionally, saturated fats are of particular concern, because an excess in the diet leads to their accumulation in the cardiovascular system, resulting in several health-related problems. Due to this, food manufacturers typically report the saturated fat vs. unsaturated fat content on the nutritional panel, allowing consumers wishing to have a healthier diet to make food choices with less saturated fat.

Determining the degree of fatty acid unsaturation of a product is difficult because foods can contain a complex mixture of saturated, monounsaturated, and polyunsaturated fatty acids with a variety of carbon chain lengths.
  • Milk and butter contain saturated C4 to C20, monounsaturated C16 and C18, and polyunsaturated C18 fatty acids.
  • Vegetable oils contain saturated C6 to C24, monounsaturated C16, and monounsaturated cis C18, C20, and C22 fatty acids.
  • Margarines contain the same fatty acids as vegetable oils plus monounsaturated trans C18, C20, and C22, and polyunsaturated C18 fatty acids.
  • Fish and meat typically contain saturated and monounsaturated C12 to C24+ fatty acids, plus polyunsaturated omega 3 C18, C20, and C22, and polyunsaturated omega 6 C18 and C20 fatty acids.
  • Fish tends to be richer in the polyunsaturated omega 3 fatty acids, whereas meats are richer in the polyunsaturated omega 6 fatty acids.

To confirm identification, very efficient capillary GC columns with the ability to resolve a large number of peaks are required. Our SPB-PUFA columns utilize a specially-developed phase for the analysis of polyunsaturated fatty acids (PUFAs) as FAMEs. It has a lower phase polarity than commonly used ′wax′ columns, resulting in a column with a slightly different selectivity. Another choice is our Omegawax, which provides highly reproducible analyses, being specially tested for reproducibility of FAME equivalent chain length (ECL) values and resolution of key components.