Evaluation of the cholesterol concentration as quality control parameter for egg noodles

Abstract

The cholesterol content has served as index of the amount of eggs in egg noodles. Resolution 12/78 of the "Comissão Nacional de Normas e Padrões para Alimentos", of the Ministry of Health (CNNPA-MS) specifies three eggs per kg of noodles, corresponding to 0.450 g of cholesterol per kg of noodles. The method used by regulatory laboratories is the colorimetric method of the Instituto Adolfo Lutz (lAL). In the present work, a comparative evaluation of two colorimetric methods, those of lAL (which utilizes acetic acid, acetic anhydride and concentrated sulfuric acid) and of Bohac et alii (which employs acetic acid saturated with ferrous sulfate and concentrated sulfuric acid), and a method which involves high performance liquid chromatography (HPLC), established in our laboratory, for the determination of cholesterol in egg noodles was carried out. For the latter method, a C_l8 column, acetonitrile-isopropanol (75:25) as mobile phase and a diode array detector were used, quantitation was carried out by external standardization. The colorimetric methods overestimated the cholesterol levels, consequently, the quantity of eggs added to the noodles. The HPLC method revealed that the five samples of egg noodles analyzed contained eggs at amounts lower than the minimum stipulated by current regulation.