Infant formula folates

INDYK HE et al. (2000), Determination of biotin and folate in infant formula and milk by optical biosensor-based immunoassay , JAOCS, 83(5), 1141-8. 

Claradiastase and trypsin in phosphate buffer have been used for hydrolysis of sample matrix for the determination of supplemental folic acid (27). Jacoby and Henry (26) further modified the method of Hoppner and Lampi (41) for folic acid by HPLC, in which the folic acid added to infant formulas and liquid medical nutritionals is quantitatively extracted with the aid of bacterial protease and papain. One disadvantage of the enzymatic extraction method was the large number of UV-absorbing compounds that are formed during enzymatic hydrolysis. These can interfere in the quantitation of the folate peaks. Thus, addition of a-amylase and protease to enhance extraction has not been common practice for methods involving HPLC. However, Pfeiffer et al. (13) suceessfiilly used triple-enzyme treatment prior to HPLC analysis with a purification method based on affinity chromatography. 

De Brouwer et al. (2010) identified 5 folate vitamers in their study 5-methyltet-rahydrofolate (the predominant vitamer), 5,10-methenyltetrahydrofolate and tetrahy-drofolate (the most labile vitamers), folic acid, and 10-formyl folic acid. This study reported that folate levels in wild-type rice were approximately 20 pg/lOO g lower than in bio-fortified rice [41], While separation of folate vitamers was obtained in 8 min run time, a previous LC-MS/MS method required 20 min [49]. Also, UPLC improved the sensitivity by reducing the limit of quantitation. Another study documented that endogenous 5-methyltetrahydrofolate in bread ranged between 1.3 and 3.4 pg/100 g [14]. Measurements of folic acid and 5-methyltetrahydrofolate in flour and infant milk formula have been successfully made using this method, described in the latter study. 

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