Characterization of iron reducibility of soy protein amyloid fibrils and their applications in iron fortification

Iron deficiency is a common nutritional disorder worldwide. Iron fortification of food is an effective strategy to control iron deficiency anemia (IDA), however, traditional iron fortificants usually provoke undesirable organoleptic changes or have limited colloid stability. In this research, we investigated iron reducibility of soy protein amyloid fibrils made from soy protein isolates (SPI), soy 13-conglycinin (7S) and soy glycinin (11S), and explored their applications in iron fortification. All three protein fibrils showed iron reducibility. The reducibility was utilized to generate fibril-iron nanoparticle composites. The iron reducibility was affected by fibril concentration, degree of fibrillation and reducing amino acid composition. We identified 11S had the most significant effect on reducing Fe (III) to more bioavailable Fe (II) state, whereas 7S showed the optimal result for generation of iron nanoparticle on fibrils in situ. The resulted fibril-iron nanoparticle hybrids showed high dispersibility in various liquid foods, without distinct color change.

Automated summary

Iron deficiency is a common nutritional disorder, and iron fortification using soy protein amyloid fibrils has been found to be effective. Soy glycinin (11S) showed the most significant effect in reducing Fe (III) to the more bioavailable Fe (II) state, while soy 13-conglycinin (7S) showed optimal results in generating iron nanoparticles on the fibrils in situ. The resulting fibril-iron nanoparticle hybrids were highly dispersible in various liquid foods without causing noticeable color changes.