Iron fortification using porous corn and wheat starches prepared by combined ultrasound and α-amylase treatments

Abstract

This study reports the fabrication of porous starches (PS) through a combined ultrasound–enzyme approach to improve iron adsorption via controlled micro-porosity and structural rearrangement. Corn and wheat starches were treated with ultrasound at 150 W (3600 s), 250 W (2400 s), and 350 W (600 s) in the presence of α-amylase (1 g/L). The resulting PS samples were characterized for water, oil, and methyl violet adsorption, while SEM and XRD analyses confirmed morphological and crystalline modifications. For iron fortification, PS samples were loaded with iron ammonium sulfate (II) (40–80 mg/L), and uptake was quantified using ICP-OES. Corn PS displayed well-developed and uniformly distributed pores, a crystallinity of 0.4709, and significantly higher adsorption capacities for water (0.6122 g/g), oil (0.3645 g/g), and methyl violet (0.7476 g/g) compared with wheat PS (crystallinity 0.5593). Maximum iron incorporation reached ∼190 mg/kg in both corn and wheat PS, though the relative improvement was greater for corn. The optimized condition (350 W, 600 s) offered high efficiency and low energy demand, highlighting corn PS as a promising, cost-effective carrier for iron fortification with potential applications in food, pharmaceutical, and cosmetic formulations.