Determination of folates in some commercial milk and fermented dairy beverages using high-performance liquid chromatography.

Folate contents in selected commercial dairy products such as pasteurized and UHT milk, fermented milk beverages and raw milk were evaluated. Folates were extracted in a 0.1 M phosphate buffer (pH 7.0), followed by deconjugation with conjugase and destruction of matrix by protease and separated by HPLC after clean-up using SAX spe cartridges. Only one form of folate - 5-methyltetrahydrofolate - was identified. The highest amount of this folate compound (6.7 μg/100g) was found in raw bulk milk. The 5-CH 3 -FH 4 content in three commercial UHT milk and five commercial pasteurized milk varied from 0.0 to 3.9 μg/100 g and from 3.3 to 5.5 μg/100 g, respectively, and 18 commercial fermented milk products contained between 0.0 and 7.4 μg /100g. Of the fermented milk beverages analyzed, buttermilk had the highest content of 5-CH 3 -FH 4 , while the amount in other fermented milk beverages was lower in comparison to the content in raw bulk milk. These results indicate that producers should pay more attention to choosing appropriate starter to improve the stability of folates during fermentation and storage which could lead to an increase in the folate content in fermented dairy products.