Folic acid is a vitamin which plays importants roles, that justify its use in enriched foods. The aim of this work was to evaluate the stability of folic acid during the shelf-life of enriched samples of powdered milk, sterilized milk and ready-to-drink milk chocolate beverages. The determination was done by high perforamance liquid chromatography. Folic acid was extracted by a basic solution and the clean-up was carried out by the addition of trichloroacetic acid, followed by filtration. In the chromatographic process, a C18 column and gradient elution were used. The mobile-phase consisted of acetate buffer and acetonitrile. Detection was carried out in the ultraviolet region, at 290nm, and quantification by external standardization. For powdered milk considerable losses of vitamin were observed (60% on average), after one year of storage For the sterilized milk and ready-to-drink milk chocolate beverage, the losses of folic acid were 25 and 29%, respectively, during the four months of storage.
folic acid; HPLC; powder milk; sterilized milk; chocolate beverages
