Search

In developing countries, complementary foods are based on local cereal porridges. These foods are poor in trace elements, with a high risk of inducing micronutrient deficiencies-the primary cause of mortality in children under the age of five. Inappropriate feeding of complementary foods is the major factor creating malnutrition and micronutrients deficiencies in Cameroon children, as well as in other developing countries. This study determined the zinc and phytate content of 30 complementary foods that were based on maize or Irish potatoes. The foods were blended or treated by dehusking, fermentation and germination. Zinc was measured by flame atomic absorption spectrophotometry and phytates by high pressure-liquid chromatography; then phytates/zinc molar ratios were calculated. Concentrations (mg/100g dry matter) ranged, respectively, from 0.20 to 2.58 (0.12 ± 0.67) for zinc and from 0.00 to 6.04 (1.87 ± 1.7) for phytates. The phytate/zinc ratio varied from 0.00 to 51.62 (11.12 ± 11.53). It appears that germination and fermentation reduced the level of phytates: however, zinc levels in the samples did not change significantly. The traditional, local complementary foods were not only poor in zinc, but contained very high levels of phytates. These phytates have the potential to considerately reduce the acid extraction of zinc, and could impair its bioavailability., (Copyright © 2012 Elsevier GmbH. All rights reserved.)

A column liquid chromatographic method that uses a spectrophotometric detector for the analysis of phytate and other inositol phosphates in foodstuffs and seeds is described. It has been tested thoroughly and sent to 6 other laboratories where there was an interest in such an analytical method and the equipment was available for performing it. These samples were blinded to the individual collaborators. Also sent was a standard wheat bran sample available from the American Association of Cereal Chemists with a standard phytate value reported as 3.2%. The postcolumn sulfosalicylic acid reaction was developed in the 1950s as an analytical method for ferric ion. All reagents are aqueous solutions and the specific pH values of each are important. The column separation is at pH 4, which dissociates all phosphate analogs. The ferric sulfosalicylate is at pH 1.8. The postcolumn reaction is then at pH 2.0-2.3. At this pH, the sulfosalicylate complexes one ferric ion and will yield it to a stronger complexing agent such as a phosphate ester. At higher pH values, sulfosalicylate complexes 2 ferric ions and will yield neither to these anions. The method sensitivity is 8-12 nmoles/injection.

A method is described that accurately and rapidly quantifies the free and total phosphorous content of a commercially available, purified, phytic acid preparation. This allows its use as a standard for phytic acid determinations in foods. The method involves a wet ashing step followed by phosphorous measurement with a 1-amino-2-naphthol-4-sulfonic acid-molybdate reagent in a microplate reader at 660 nm. The procedure can be performed in 3 h with as little as 50 mg sample.

Phytate, a naturally occurring organic compound found in plant seeds, roots, and tubers, was determined in a collaborative study using a modified anion-exchange method. Seven samples (peanut flour, oats, rice, isolated soybean protein, a vegetarian diet composite, wheat bran, and whole wheat bread), supplied as blind duplicate samples, were analyzed in triplicate by 7 collaborators. Phytate concentrations in the samples ranged from 2.38 to 46.70 mg/g. Relative standard deviations (RSD = CV) for repeatability ranged from 2.5 to 10.1%, and for reproducibility, from 4.5 to 11.0%. The method has been adopted official first action.

The phytate content of several foods is presented. Published zinc values were used to calculate phytate:zinc molar ratios. These ratios can be used to estimate the relative risk of having an inadequate intake of zinc. They may be used in planning menus to select the combination of foods that will supply the most available zinc to the daily diet. On the basis of animal experiments to date, a daily phytate:zinc molar ratio of 10 or less is thought to be acceptable in providing adequate dietary zinc, and daily ratios consistently above 20 may jeopardize zinc status. Many factors other than the daily dietary phytate:zinc molar ratio influence zinc nutriture, but the ratio concept is a tool which may contribute to a more accurate assessment of zinc status.