Problems associated with measuring phytate in infant cereals.
The inositol hexaphosphate (IP6) content of commercially available dried infant cereals was measured by ion pair high-pressure liquid chromatography (ion pair HPLC) and ion exchange high-pressure liquid chromatography (ion exchange HPLC). Large differences between methods were apparent: ion pair HPLC gave values 14 to 190-fold lower than the values from ion exchange HPLC. Poor recoveries of added IP6 (25 to 60%) by ion pair HPLC suggested that some component of the infant cereal was responsible for the difference. Further experimentation suggested that an excess of minerals (approximately 11 mg/g calcium and 0.3 mg/g iron) in these samples sequestered the endogenously low phytate content. This problem may be unique to samples with low IP6 and high mineral content as wheat bran was not problematic. These results suggest that ion exchange HPLC is the method of choice for measuring inositol phosphates in infant cereals.
Nutrition Research Division, Health Protection Branch, Health Canada, PL2203C Banting Research Centre, Tunney's Pasture, Ottawa, ON, Canada K1A 0L2. Steve_Brooks@hc-sc.gc.ca
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Lampi
D016477:Artifacts; D018554:Avena / Q000737:chemistry; D002118:Calcium / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002852:Chromatography, Ion Exchange / Q000379:methods; D002523:Edible Grain / Q000737:chemistry*; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000032:analysis*; D007501:Iron / Q000032:analysis; D010833:Phytic Acid / Q000032:analysis*; D015203:Reproducibility of Results; D014908:Triticum / Q000737:chemistry
D010833:Phytic Acid; D007501:Iron; D002118:Calcium