title: [Intake of folic acid in the total daily diet--effect of food preparation on its folic acid content].
abstract: The folic acid content of total daily diet was determined by means of high-performance liquid chromatography (HPLC). The contents of tetrahydrofolic acid (THF), 5-methyl-THF and 5-formyl-THF were differentiated. The mean of the folic acid content of the total daily diet samples determined analytically was 205 +/- 60 micrograms and the mean of the individual ingredients of the samples was 401 +/- 78 micrograms, which implies that about 50% of folic acid is destroyed by common household food preparation methods. If the contents of pteroylglutamic acid (PteGlu) and 10-formyl-PteGlu (which cannot be determined analytically) are added, it can be assumed that the folic acid content with only be reduced by about 40%. THF and 5-methyl-THF proved to be less stable than 5-formyl-THF. The monoglutamate portion of the total folat content was higher in the total diet samples than in the individual foodstuffs as a consequence of the action of the enzyme "deconjugase" which is released when the matrix of food-stuffs is destroyed.
authors.affiliation: Institut für Ernährungsphysiologie, Bundesforschungsanstalt für Ernährung, Karlsruhe, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Müller
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004032:Diet; D005492:Folic Acid / Q000032:analysis*; D005504:Food Analysis; D005511:Food Handling; D006801:Humans; D002955:Leucovorin / Q000032:analysis; D013763:Tetrahydrofolates / Q000032:analysis
chemical_list: D013763:Tetrahydrofolates; C030371:5,6,7,8-tetrahydrofolic acid; D005492:Folic Acid; D002955:Leucovorin; C005984:5-methyltetrahydrofolate
vernacular_title: Die Folsäure-Aufnahme mit der täglichen Gesamtnahrung--Einfluss der Speisenzubereitung auf deren Folsäure-Gehalt.