Compromised zinc status of experimental rats as a consequence of prolonged iron & calcium supplementation

Background & objectives: Iron supplementation is usually given to pregnant and lactating women who may also have marginal deficiency of zinc. The negative impact of supplemental iron and calcium on zinc status is a cause of concern. The present investigation was undertaken to examine the effect of inclusion of iron and calcium in the diet at supplementary levels on zinc status of experimental rats. Methods: Groups of experimental rats were maintained on diets supplemented with iron (Molar ratio - Zn:Fe 1:30) and calcium (Molar ratio - Zn:Ca 1:667) both individually and in combination for six weeks. Zinc status of these rats was assessed by determining zinc concentration in circulation and in organs, and the activities of zinc containing enzymes in serum and liver. Results: The zinc status of experimental rats receiving supplemental levels of iron and calcium was significantly compromised. Zinc concentration in serum, kidney, spleen and liver was reduced significantly by both these minerals. Six weeks of supplementation of iron and calcium individually, significantly reduced the activity of liver and serum superoxide dismutase and alkaline phosphatase. Activity of liver alcohol dehydrogenase was lowered in calcium supplemented group and in calcium + iron supplemented group, while that of carbonic anhydrase was significantly reduced by iron, calcium and their combination. Interpretation & conclusions: Supplemental levels of iron and calcium, both individually and in combination, significantly compromised the zinc status of experimental rats. This negative effect of these two minerals was more prominent when these were supplemented for a period of six weeks

Bioaccessibility of minerals from cereal-based composite meals and ready-to-eat foods

Mineral content and bioaccessibility of 4 home-made composite meals and 6 commercial ready-to-eat (RTE) foods were assessed. Bioaccessibility of Fe from composite meals based oil 4 staple cereals ranged from 1.5% (finger millet meal) to 4.7% (wheat meal), while that of Zn, from 8.5% (rice meal) to 0.31% (sorghum meal) and of Ca, from 5.1% (wheat meal) to 9.8% (rice meal). Rice and finger millet meals provided more bioaccessible Zn and Ca, while wheat and sorghum meals had more bioaccessible Fe. Commercial RTE foods provided more bioaccessible Zn and Ca than the corresponding whole meals. Thus, intake of minerals is not compromised by consuming the traditional RTE foods instead of regular home-cooked meals

Determination of bioaccessibility of β-carotene in vegetables by in vitro methods

Abstract The in vitro method in use for the determination of β-carotene bioaccessibility involves simulated gastrointestinal digestion followed by ultracentrifugation to separate the micellar fraction containing bioaccessible β-carotene and its quantitation. In this study, the suitability of two alternatives viz., membrane filtration and equilibrium dialysis were examined to separate the micellar fraction. Values of β-carotene bioaccessibility obtained with the membrane filtration method were similar to those obtained by the ultracentrifugation method. Equilibrium dialysis was found not suitable for this purpose. Among the vegetables analyzed, fenugreek leaves had the highest content of β-carotene (9.15 mg/100 g), followed by amaranth (8.17 mg/100 g), carrot (8.14 mg/100 g) and pumpkin (1.90 mg/100 g). Percent bioaccessibility of β-carotene ranged from 6.7 in fenugreek leaves to 20.3 in carrot. Heat treatment of these vegetables by pressure cooking and stir-frying had a beneficial influence on the bioaccessibility of β-carotene from these vegetables. The increase in the percent bioaccessibility of β-carotene as a result of pressure-cooking was 100, 48 and 19% for fenugreek leaves, amaranth and carrot, respectively. Stir-frying in presence of a small quantity of oil led to an enormous increase in the bioaccessibility of β-carotene from these vegetables, the increase being 263% (fenugreek leaves), 192% (amaranth leaves), 63% (carrot) and 53% (pumpkin)

Improved shelf-life of rice bran by domestic heat processing and assessment of its dietary consumption in experimental rats

Rice bran, a valuable byproduct of the rice milling industry, in spite of being a rich nutrient, has limitations in food application, being highly susceptible to rancidity caused by the inherent enzyme lipase. In the present investigation, three simple heat treatment procedures, namely pan roasting, pan roasting with oil and microwave roasting, were examined to extend the shelf-life of three varieties of rice bran. In the heat-treated rice brans, the increase in free fatty acid content at the end of a 3-month storage period was 1.6- to 2.5- fold as a result of heat treatment, while it was 12- to 23-fold in the absence of heat treatment. In an animal experiment, pan-roasted rice bran was fed to rats at 5% and 10% levels to study the palatability and safety of its consumption. The mean food intake was slightly higher in the 10% rice bran group (13.57 ± 0.2 g compared to 12.31 ± 0.52 g in control). Rats in the 10% rice bran group gained higher body weight when compared to the control group, which can be attributed to the higher food consumption by these animals. Dietary rice bran did not have any adverse effect on any of the hematological parameters. Serum protein level was similar to that of the control group except for an increase in serum albumin in rice bran-fed groups, which is indicative of liver sufficiency in rice bran treatment. The weights of liver, kidney, heart and testes were not affected by rice bran either at the 5% or 10% level. It is inferred that simple domestic heat treatment procedures such as pan roasting and microwave heating can effectively check the rancidity in rice bran for a considerable period of storage, making it suitable for possible animal/human consumption. Copyright © 2006 Society of Chemical Industr