Combining the Folch method with a simplified alternative fat extraction technique for use in a colorimetric assay to measure the degree of unsaturation in fat samples in a biochemistry laboratory

Abstract

The Folch method is a commonly employed, simple biochemical procedure used to extract fat from food items and biological samples in biochemistry laboratories. The iodine number of fat reflects its degree of unsaturation. In the present study, the iodine number of fat extracted using the Folch method from cow milk, goat milk, chicken egg yolk and coconut milk was determined using a simple colorimetric procedure that comprises an iodine solution in ethanol and a starch solution, replacing the Wijs reagent and conventional titration procedures with sodium thiosulfate standard solutions. Resembling the Folch method, a low-cost alternative approach, utilizing kerosene oil, isopropyl alcohol, and water, which can be used to extract fat from commonly consumed liquid food items, was also developed in the present study as a simple and reliable approach. The extracted fat from the proposed method can be sent to a biochemistry laboratory to determine the iodine number using the proposed 96-well plate-based colorimetric procedure. The proposed methods are suitable for laboratories in low-income settings.