[Effects of cooking methods on iodine content in iodized salt]

Effects of cooking methods and variety of foods on the retention of iodine content in food with iodized salt were studied. Vegetables from market and usual cooking methods were selected, including procedures of various cooking methods. The samples were fixed by potassium carbonate, ashed with zinc sulfate at 550 degrees C, then determined by colorimetric method with Ce-As-I catalytical reaction. The different cooking methods had different effects on the retention of iodine, in general, the retention of iodine by stewing of steaming was higher than by stir-frying. The effect of various vegetables on the retention of iodine was also different. The retention of iodine after stir-frying was 84.2%, 56.9%, 44.5%, 36.6% for fruit-bearing vegetables, leafy vegetables, roots and beans. The retention of iodine after stewing was 66.1%, 53.4%, 47.0%, and 43.2% for fruit-bearing vegetables, roots, beans and meat. The stability of organic iodine in food is higher than that of inorganic iodine.