Capillary electrophoresis and high-performance liquid chromatography determination of polyglutamyl 5-methyltetrahydrofolate forms in citrus products.
The 5-methyltetrahydrofolate (5mTHF) polyglutamates in citrus products were analyzed by capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC). Folate species were purified from citrus products and concentrated from 2- to 100-fold using combined folate-affinity chromatography and C18 extraction. Seven polyglutamyl 5mTHFs were found in most not-from-concentrate (NFC) orange juices (OJ) in total amounts of approximately 1 nmol/mL, with varying distributions of individual polyglutamates. Folate amounts and distributions were also measured in orange fractions, single-strength OJ from concentrate, NFC grapefruit juice, and citrus peel molasses. Models containing ascorbic acid had folate thermal degradation rates one-seventh that of models without ascorbic acid. Pasteurization studies demonstrated that folate loss was <2% for commercial OJ pasteurization conditions (i.e., 93 degrees C for 5 s, 88 degrees C for 15 s, and 82 degrees C for 30 s). Both methods were precise, reproducible, and potentially faster than traditional analytical procedures requiring enzymatic deconjugation and microbial assays.
Matella
Norman J
NJ
Food Science and Human Nutrition Department, University of Florida, IFAS, Citrus Research and Education Center, 700 Experiment Station Road, Lake Alfred, Florida 33850, USA.
Braddock
Robert J
RJ
Gregory
Jesse F
JF
Goodrich
Renée M
RM
D001628:Beverages / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D002957:Citrus / Q000737:chemistry*; D032084:Citrus sinensis / Q000737:chemistry; D019075:Electrophoresis, Capillary; D005638:Fruit / Q000737:chemistry; D011624:Pteroylpolyglutamic Acids / Q000032:analysis*; D013763:Tetrahydrofolates / Q000032:analysis*
D011624:Pteroylpolyglutamic Acids; D013763:Tetrahydrofolates; C005984:5-methyltetrahydrofolate