title: Protocol for the production of concentrated extracts of food folate for use in human bioavailability studies.
abstract: To provide a tool to study folate bioavailability under controlled conditions, a methodology was developed to produce extracts representative of natural food folates but removed from their matrix and sufficiently concentrated so as to elicit a response in biomarkers of folate status without distorting usual dietary intake patterns. Egg, spinach, and yeast were selected to represent the wide range in extent of folate conjugation found in foods (0, 60, and 100% polyglutamyl folate, respectively). The protocol, which was based on extracting food folates using only reagents safe for human consumption, was optimized in the laboratory (thermal extraction for 10 min in a 2% ascorbate solution at pH 5) and then adapted for industrial scale production in a food-processing facility. Results showed that the extracts were 2.3-12 times more concentrated in folate compared with their corresponding food sources. Neither the mono- to polyglutamate ratio nor the distribution of the main folate derivatives was altered during processing, making these extracts suitable for use in human bioavailability studies.
authors.affiliation: Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, Northern Ireland BT52 1SA.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: McKillop
authors.forename: Kristina D
authors.initials: KD
authors.lastname: Pentieva
authors.forename: John M
authors.initials: JM
authors.lastname: Scott
authors.forename: J J
authors.initials: JJ
authors.lastname: Strain
authors.forename: Richard
authors.initials: R
authors.lastname: McCreedy
authors.forename: Joy
authors.initials: J
authors.lastname: Alexander
authors.forename: Karen
authors.initials: K
authors.lastname: Patterson
authors.forename: Joan
authors.initials: J
authors.lastname: Hughes
authors.forename: Helene
authors.initials: H
authors.lastname: McNulty
mesh_terms: D001682:Biological Availability; D004530:Egg Yolk / Q000737:chemistry; D005492:Folic Acid / Q000032:analysis* / Q000493:pharmacokinetics*; D005504:Food Analysis; D005516:Food Microbiology; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D012441:Saccharomyces cerevisiae / Q000737:chemistry; D018724:Spinacia oleracea / Q000737:chemistry
chemical_list: D005492:Folic Acid