Study on stability of iodine in iodated salt by use of different cooking model conditions

Abstract

Different cooking methods, utensils, and cooking conditions were utilized along with the addition of various food additives, sugars, fortificants, spices and sanitizer, to evaluate their effects on iodine in the food. Evaluations used 20% salt brine as the model in order to avoid complications with the real food system. Titration and spectrophotometric methods were used for iodine analysis based on the kind of sample prepared; the analyses were performed along with a blank sample that contained the same chemicals except iodated salt. Significant loss (P = 0.05) of iodine was analyzed by using either ANOVA with Scheffe or t-test. Cooking methods (boiling, frying, steaming, baking, canning) and pHs (3, 6, 9) showed no significant effect on iodine loss. Metal utensils significantly affected iodine loss. With the addition of either sodium metabisulfite (50-250 ppm) or ascorbic acid (0.1 and 0.5%), iodine in salt was totally lost at the higher concentration even before cooking. High loss of iodine was found in the samples with glucose (5%) and lactose (5%) at pH 9 after cooking especially with brass utensil; the sucrose sample showed a loss of 33% at pH 3. Conversely, high losses of iodine were found in all cooking utensils, except with brass, after adding ferrous sulfate (0.05 and 0.1%). High losses were found during cooking with phosphoric acid in brass at pH 3. Color interference acid in brass utensil in all trials at all pH values. Garlic, fresh chili, pepper, and green curry paste caused high loss of iodine. © 2002 Published by Elsevier Science Ltd.