IRON BIOAVAILABILITY FROM AMARANTHUS SPECIES - 1 - IN-VITRO DIALYZABLE IRON FOR ESTIMATION OF GENETIC-VARIATION

Green leafy vegetables have the potential to contribute significant am ounts of iron to the diet, if the bioavailability of iron from these f oods is improved. In order to determine the potential for genetic mani pulation of this trait, 46 lines from 12 species of Amaranthus were ev aluated for total and bioavailable iron in greenhouse and field experi ments. Bioavailable iron was estimated using an in vitro assay for dia lysable, low-molecular-weight iron compounds. Significant differences (P < 0.01) were detected among lines and species for total and bioavai lable iron. Total iron ranged from 358 to 880 ppm (dry weight) in fiel d-grown plants and 55 to 123 ppm (dry weight) in greenhouse-grown plan ts. Bioavailable iron ranged from 41 to 63 ppm in field-grown plants a nd from 24 to 51 ppm in greenhouse-grown plants. Amaranthus tricolor a nd A lividus had the highest total and bioavailable iron; A hypochondr iacus had the lowest levels of the species tested. Although field-grow n Amaranthus accumulated higher levels of total and bioavailable iron, a greater proportion of the total iron was sequestered in insoluble, unavailable forms. Generally, species with higher total iron had highe r levels of bioavailable iron. These analyses indicated potential for genetic improvement of iron nutritional quality from Amaranthus, espec ially within the species A tricolor. (C) 1998 Society of Chemical Indu stry.