Gas chromatographic determination of cholesterol in egg products.

A method has been developed for quantification of cholesterol in fresh egg yolks, spray-dried egg yolks, fresh whole eggs, and spray-dried whole eggs. The method uses saponification followed by petroleum ether extraction of cholesterol. Separation of organic and aqueous layers is enhanced by sodium chloride. Petroleum ether extracts are dried under nitrogen and redissolved in chloroform-methanol (2 + 1) for injection into a gas chromatograph. Cholesterol is separated and quantitated on a high temperature capillary column coated with 5% diphenyl and 95% dimethyl polysilicone crosslinked gum. The method was compared with the current AOAC method 17.017-17.022, and results indicated no significant difference (alpha = 0.05). However, the proposed method allowed separation and analysis of 16 samples in 7 h while the current AOAC method allowed separation and analysis of only 4 samples in 9 h.