Enrichment of broccoli seedlings with iron and its impact on germination, antioxidant activity, and the level of phenolic compounds

Biofortification of edible seedlings (sprouts) is a promising strategy to combat dietary nutrient deficiency. In the present study, we made an attempt to enrich broccoli seedlings through imbibition with Fe at two concentrations, 100 mg Fe · dm–³ and 500 mg Fe · dm–³, of four chemical forms: FeCl₂, FeCl₃, FeSO₄, or Fe₂(SO₄)₃. The imbibition in all of the solutions resulted in a significant increase in Fe content in the seedlings, wherein it was the highest by the imbibition in sulphates applied at the highest concentration (500 mg·dm⁻³). In addition, the imbibition in sulphates in general did not affect the germination rate, whereas the imbibition in chlorites hampered the germination process. The application of Fe at a concentration of 500 mg Fe · dm–³ in the form of FeSO₄ enhanced antioxidant activity, while the application of Fe in the form of FeCl₂ and FeCl₃ stimulated the accumulation of anthocyanins. It can be concluded that seed imbibition in Fe in the form of FeSO₄ is an easy and cheap method for biofortification of broccoli seedlings, leading to a nearly 10-fold increase in Fe content and significant enhancement of antioxidant activity, without affecting the germination rate.