Effect of adding different thickening agents on the viscosity properties and in vitro mineral availability of infant formula

The effect of adding different thickening agents (locust bean gum (LBG), modified corn and rice starches (MCS, MRS)) to an infant formula on both in vitro mineral availability (Ca, Fe and Zn), quantified by atomic absorption spectrophotometry (AAS), and formula viscosity, after in vitro gastrointestinal digestion, was investigated. LBG was the most effective agent to increase formula thickness. However, it showed a negative effect on Ca, Fe and Zn in vitro solubility and dialysability. MCS and MRS only affected calcium solubility and dialysability when they were used at ⩾50% of the maximum legal limit. No negative effect was observed for Fe and Zn when modified starches were added at the different concentrations assessed. The phytate content in the thickening ingredients was also analysed. Despite finding a considerable amount of phytic acid in the raw ingredients, its final concentration in the infant formula was insufficient to decrease in vitro mineral availability.