Time–intensity characteristics of iron compounds

Discrete-interval time–intensity scaling was used to measure the sensory characteristics of three iron compounds, 0.05 M ferrous sulfate, 0.03 M ferrous chloride and 0.05 M ferrous gluconate. All three compounds exhibited strong and persistent metallic flavors. Ferrous chloride was highest in bitter taste and ferrous gluconate highest in initial sourness and astringency. Evidence of anionic inhibition was seen in that ferrous gluconate was lower in bitterness relative to ferrous chloride. Taste properties decayed rapidly over the 2-min test period but astringency had slower onset, reached a maximum at 60 s and remained at or near the maximum level during the test period. These common iron fortifying agents show complex and different sensory profiles. The sensations that are predominant change over time, with a lingering astringency and metallic taste that may lessen their suitability for use in food fortification.