الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Introduction The thyroid gland is the largest gland in human body; weighting about 20 gm in an adult. The thyroid gland secrets two .honnones ; The thyroxine and tri iodothyroxine , that are commonly known as T 4 and T 3 . The thytroid hormones have many actions and are important for growth, development and sexual maturation .. Iodine is a trace element present in the human body and its only confirmed role is in the synthesis of thyroid honnones . Iodine deficiency will therefore impair thyroid honnonogenesis. This results in many pathological conditions called iodine deficiency disorders (IDD). These include endemic goitre and critinism , decreased fertility, increased prenatal and infant morbidity and mental retardation. Prevention and treatment of IDD by administration of iodine is used since ancient times-for prophylaxis and treatment of IDD . Iodine has been added to various foods including water supply, oil, bread, milk, salt and even chocolate. The general use of iodized salt in goitrous patients. Now iodized salt is widely used all over the world as a the best effective method for prophylaxis and also treatment of endemic goitre. This fact justifies continuing evaluation of this method of treatment to optimize its effectiveness. . Aim of The Work This study was carried out to assess the following parameters. The effect of extreme conditions of storage on the stability of iodized salt. The effect of cooking techniques on the percentage of iodine in iodized salt. 1. .. Materials and methods Materials Salt (iodized or non-iodized) was obtained from El Nasr Malahat Company through out this study: Storage samples a) Three batches of iodized salt were obtained to carry out storage experiments. Each comprises 3 kg . Three batches of non-iodized table salt were supplemented with a known iodine concentration (100 mg 12 / Kg salt)and a known con~entration of stabilizing agent (KI to NaC03 = 1 :20) , for control experiments at our laboratories at High Institute of Public Health . b) I/. Storage experiments The samples of iodized salt, (200) gm each, were stored for six months at : a) Room temperature (23-27°C) . b) 37°C. ’ c) 10°C (refrigerators) . These samples were analysed initially and then every three weeks up to 6 months. Ash analysis (water insoluble matter) and proximate analysis were carried out in all samples stored at room temperature. As such parameters will not be affected by storage at 10°C and 37°C. II/. Cooking experiments The samples of iodized salt were added to potato pIeces undergoing: i) Boiling ii) Oven roasting r These samples were analysed for their iodine content pre and 1 post cooking to determine the loss due to cooking. i A. Boiling experiments i B- Oven roasting experiment , ; C- Detennination of iodine concentration post cooking IV. Survey analysis (market) samples . . ~ .. . . ’ . . Fifty (50) random samples of iodized salt were purchased from 1 fifteen (15) supermarkets in Alexandria; for survey analysis. I Twenty five (25~ sc:unples were Lite iodized salt; and twenty five ~ (25) were Maxx lodlzed salt. j , I Methods of chemical analysis I i ;, ’j 1 ;j ! i ! All samples were analysed according to AoAc to determine the percentage of : a) Iodine b) c) Water in soluble matter (ash) d) e) Magnesium 1) g) Calcium h) Moisture Calcium carbonate Sulphate Heavy metals (Cd,Ni ,Pb) .. Results Results obtained from this work can be summarized as follows: 1. Iodine concentration Three batches of a freshly manufactured iodized salt curtesy of EL-Nasr Malahat Company, were analysed immediately following arrival at the laboratory, and then at three weeks interval up to six months demonstrates that in all batches that were stored at room temperature, iodi.zed salt lost about 40/0 of its iodine content by the 6th week and about 17 by 22 weeks, the iodine content of those batches that were stored at 37°C reduced significantly by about 38 by the 9th week. Minimal loss in iodine content was found in the batches that were stored at 100e . Storage experiments for control samples where a stabilizer was added: There was minimal loss of iodine 12 content in iodized salt that stored at different degrees of temperatures 1.8 at 22 weeks. 11.. Water insoluble matters ”Ash content” The results show no or minor changes in the level of ash during storage which may be due to error in reading the results.