Stability of tocopherols in adapted milk-based infant formulas during storage

Abstract

Abstract An evaluation is made of the effects of added α -tocopherol ( α -T) or α -tocopherol acetate ( α -TAc) combined with iron lactate or sulfate, storage time (up to 17 months) and storage temperature (22°C and 37°C) on the α -TAc, α -T, γ -tocopherol ( γ -T) and δ -tocopherol ( δ -T) content of infant formulas. Tocopherols were measured by normal phase HPLC and fluorescence detection after direct extraction, which allows the determination of both α -TAc and α -T. The α -TAc content was not affected by temperature or storage time, although the α -, γ - and δ -T contents, which were lower at 37°C than at 22°C, were significantly affected. The type of iron salt added (lactate or sulfate) exerted a significant effect on the α -T and α -TAc content. By the end of the storage period studied, all tocopherols had decreased by ⩾50%, although the total vitamin E activity exceeded 0.1 α -T equivalents 100 kJ −1 , i.e., the minimum content established by European law.