A simplified alternative to the AOAC official method for cholesterol in multicomponent foods.
An AOAC official method for quantitating cholesterol in multicomponent foods, which was first published in the 13th edition of the Official Methods of Analysis, is rarely used. The method includes so many operations and manipulations--all described in excruciating detail--that most laboratories shun it altogether. Intent on finding an alternative, laboratories have developed their own methods for specific foods. As a result, new methods have proliferated, but still no practical method has been developed for the broader categories of multicomponent foods. The aim of AOAC, which is to promote greater accuracy and uniformity of analytical results primarily through collaborative testing, has not been well served under these circumstances. A different approach guided the work reported in the present paper. This approach was directed toward updating and dramatically simplifying the existing AOAC official method. The method's chloroform-methanol-water mixed-solvent extraction is preserved; however, all the remaining steps have been streamlined, updated, or eliminated by using newer technology. Cholesterol is quantitated with highly specific capillary gas-liquid chromatography using the internal standardization technique. The lipid extract is prepared for the chromatography step by a brief saponification carried out in a culture tube. The resulting method has been validated by using Standard Reference Materials and the standard addition method. Because a simplified method is now available for quantitating cholesterol in the lipid extracts, the expectation is that more attention can be given to the development of improved and efficient extraction methods. This step remains as the central difficulty in any number of methods of analysis for lipid analytes.
Thompson
R H
RH
U.S. Department of Agriculture, Agricultural Research Service, BHNRC, Nutrient Composition Laboratory, Beltsville, MD 20705.
Merola
G V
GV
D002784:Cholesterol / Q000032:analysis* / Q000302:isolation & purification; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D005504:Food Analysis / Q000379:methods* / Q000592:standards; D016018:Least-Squares Analysis; D012015:Reference Standards; D015203:Reproducibility of Results
D002784:Cholesterol