Determination of in vitro availability of iron from common foods
Das, P.; Raghuramulu, N.; Rao, K.C.
Journal of Human Ecology 18(1): 13-20
2005
ISSN/ISBN: 0970-9274 DOI: 10.1080/09709274.2005.11905800Document Number: 264259
Some common foodstuffs of plant origin were analyzed spectrophotometrically using derivative spectroscopy for total and in vitro available iron (ionizable iron). Though rice had lowest total iron content (0.61 +/- 0.09 mg/100g), the percent ionizable iron was highest (29.50 +/- 4.75%) as compared to all other cereals and millets tested and also comparable to some of the whole pulses analyzed. Similarly, maize with comparatively lower total iron content (2.73 +/- 0.14 mg/100g), had a higher percent ionizable iron (25.30 +/- 1.46%). The whole pulses were found to contain total iron ranging from 4.40 +/- 0.30 mg/100g in blackgram to 6.36 +/- 0.55 mg/100g in rajmah, but except Bengal grain (white) (21.71 +/- 0.53%), pea (35.66 +/- 4.44%) and rajmah (24.05 +/- 1.42%), others showed very low ionizable iron (3.41 +/- 0.22-6.53 +/- 1.31%). Split pulses had a better percentage of ionizable iron (13.80 +/- 0.73-31.70 +/- 1.74%) compared to whole pulses, which could possibly due to removal of some inhibiting factors present in the seed coat. Though green leafy vegetables had comparatively lower amount of total iron (1.82 +/- 0.11-3.76 +/- 0.23 mg/ 100g), it had a high ionizable iron from 30.22 +/- 1.10 to 52.13 +/- 1.90%. Endogenous levels of ascorbic acid and tannin present in the food samples evaluated had no direct influence on iron availability. The results by spectrophotometric method were further compared with radioistopic method by extrinsic tagging of a few samples with Fe-59. A significant positive correlation (r=0.986; P<0.001) was observed between the two methods.