45I-14 |
Iron bioavailability from the root nodules of soybean (Glycine max) - evaluation in a rat hemoglobin regeneration bioassay |
A. K. PROULX1, Y. Kakuda1, and G. W. Bassel2. (1) Dept. of Food Science, Univ. of Guelph, Food Science Bldg., Guelph, ON N1G 2W1, Canada, (2) Dept. of Botany, Univ. of Guelph, Axelrod Bldg., Guelph, ON N1G 2W1, Canada Sources of iron in nutrition have typically been classified as either heme iron or non-heme iron. Heme iron has always historically been associated with meat based foods. Legumes, and particularly soybeans, create nodular root structures which are capable of creating a heme iron containing protein, leghemoglobin, comprising about 26% of the total iron store in the nodule, and storing total iron at levels of up to 2.5mg/g dry weight basis. Establishing the bioavailability characteristics of a plant sourced heme iron was the primary objective. Using a rat hemoglobin repletion model, animals were fed diets containing iron almost exclusively from one of 3 sources, soy root nodules, bovine hemoglobin, or ferrous sulphate (control) each at three predicted levels of iron, 5, 15 or 25ppm. Slope ratio analysis (SRA) as modified from the AOAC model indicated that soy root nodules and bovine hemoglobin exhibited Relative Biological Value (RBV) 63% and 55% for soy nodule and bovine hemoglobin respectively when analysed in the dose response curve in comparison to ferrous sulphate. This difference was not statistically significant at the p <0.05 level. Hemoglobin repletion efficiency (HRE) at the presumptive dose rate 25ppm indicated that bovine hemoglobin supported a similar repletion efficiency to soy root nodules at 45.8 and 44.5 respectively and relative biological value based on HRE at 60% versus 59% respectively. These values are not statistically significant at the p <0.05 level. These results indicate that soy root nodule as a fortificant responds similarly to bovine hemoglobin in terms of hemoglobin repletion efficiency. By displaying a hemoglobin repletion efficiency similar to many iron fortified foods, and a repletion efficiency as high or higher than typical plant foods, this indicates the potential use of soy or legume nodules as a bioavailable and concentrated source of plant heme iron pending further research.
Session 45I, Nutrition: General
|