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Improved procedure for extracting food fatty acids
Author(s) -
Lough A. Kenneth,
Navia Juan M.,
Harris Robert S.
Publication year - 1966
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02640801
Subject(s) - chemistry , extraction (chemistry) , chloroform , fatty acid , methanol , chromatography , hydrochloric acid , solvent , calorie , food science , solvent extraction , organic chemistry , biology , endocrinology
Estimations of the fat content of food are generally based on the weight of the fraction extracted by a solvent. Unfortunately these solvents extract varying amounts of substances which are nonlipids, and they fail to extract all of the fatty acids, especially those present in complex forms. Though current procedures are simple, they are unreliable. Calories contributed by food fats can be calculated accurately only from data on the total fatty acid content of these foods. An improved method for the complete extraction of food fatty acids is described. This method involves an extraction of food samples with chloroform: methanol (2蝘1) both before and after treatment with 2 N hydrochloric acid in methanol, removal of the solvent from the combined extracts, and then extraction with chloroform. This method was compared with the AOAC method in the analysis of 18 foods for fatty acid content. The values obtained by the new method were higher in every case, and significantly higher in most cases, due primarily to a more complete extraction of the bound fatty acids. The usefulness of the new method in the routine analysis of foods was demonstrated in 58 additional food samples.