Cholesterol

Isolation of Cholesterol

This experiment uses egg yolk samples. Isolation of cholesterol begins with the addition of a solution of ethanol and ether with perbandungan 2: 1. Ethanol tends to be polar and nonpolar ether which tends to be a combination of solvent can dissolve the phospholipids that are ampifatik, cholesterol, and triglyceride levels in the egg yolk. Then do the filtration to separate the fat dissolved in ether and ethanol with other components such as pigments (lutein and astaxantin) and protein. The resulting filtrate is colorless (clear) and a yellow precipitate. This is consistent with the theory Gunawan (2009) as described in the literature.

Precipitated and then rinsed with hexane to dissolve the lipid component extracted did not participate in the early stages. Hexane is an excellent solvent for extracting neutral lipid components. Furthermore, the results of the extract is poured into a separating funnel and allowed to stand for ± 30 minutes to separate the components are soluble in hexane fats (triglycerides) with fat-soluble components elarut ethanol-ether (cholesterol and phospholipids). Hexane solvent will be at the top of the funnel, while ethanol-ether will be at the bottom of the funnel. This is due to a lower density than ethanol hexane-ether. (Palacios and Wang, 2005)

The next stage is the heating. Warming aims to evaporate the organic solvent so that only leaves the fat component. This can happen because the solvent boiling point lower than the boiling point of the fat. Further cold acetone added to the heating components that dissolve fat, which is alcohol. White precipitate formed which is a phospholipid / lecithin. This is consistent with the theory Szuhaj (1989) described in the literature.

Salkowski test conducted on the final filtrate produces red ring between the two layers. These results suggest that the positive yolk contains cholesterol.