[The determination of the folic acid content of foods of animal origin using high performance liquid chromatography (HPLC)].

The folic acid content of food of animal origin was determined by means of high-performance liquid chromatography (HPLC). Free folate (monoglutamate forms) and total folate (monoglutamate + polyglutamate forms) were differentiated. Liver (bovine 963, hog 136 micrograms/100 g) and kidney (bovine 410, hog 93 micrograms/100 g) contained the highest content of total folate, followed by egg (67 micrograms/100 g), soft cheese (44-62 micrograms/100 g), milk and other dairy products (3-28 micrograms/100 g). Chicken, fish, beef and pork contained only a low content of total folate (1-12 micrograms/100 g). The free folate portion ranged from 14.7 to 100% (mean 69.2%). The main folate derivatives tetrahydrofolic acid (THF), 5-methyl-THF and 5-formyl-THF showed the following distribution. In milk and milk products the mean was 70% for 5-formyl-THF, 20% for 5-methyl-THF and 10% for THF; in the other products the three derivatives were distributed about equally but the range of variation was high.