en Nutrition Nutrition پژوهشي Research <strong>Background and Objectives: </strong>Previous research has established that Vitamin D₃ (Cholecalciferol) deficiency is considered to be a highly prevalent nutritional problem worldwide. Data from National Food and Nutrition Surveillance Program (2015) revealed that prevalence of vitamin D₃ deficiency in Iran is more than 70% of the population. Vegetable oils are considered to be potential candidates for fortification with vitamin D₃. Although exposure to high temperatures has been shown to cause adverse effects in vitamin D₃ content of food products, research to date has not yet determined the stability of added vitamin D₃ in vegetable oils during cooking procedures.<br> <strong>Materials and Methods: </strong>An 80/20 % (eighty/twenty) mixture of fortified oils/water subjected to low temperature (105&deg;C, for 0, 60, 120 and 180 minutes) and high temperature (160&deg;C, for 0, 5, 10, 15, 20, 30, 60 minutes) under reflux condition in order to determine the destruction rate of vitamin D₃. The vitamin D₃ concentration was determined by HPLC method with following operating conditions: apparatus, SHIMADZU10-ATVP; column, C18 column, 5 mm, 150_4mm id; mobile phase, methanol; ambient temperature; flow rate, 1.0 ml/min<br> <strong>Results: </strong>This study has identified that retention rate of added vitamin D₃ in corn, sunflower and canola oils during normal cooking process varies from 68.6% to 87.4%.<br> <strong>Conclusions: </strong>This study has shown that retention of added vitamin D₃ in various vegetable oils depends on the range of natural vitamin D₃ retention in cooking of foodstuffs. This result will be of interest to clinical researchers and policymakers concerned with the fortification of food products mainly vitamin D₃fortification_.<br> &nbsp; Vitamin D3, Vegetable oils, Fortification, Cooking, Stability 43 48 http://nfsr.sbmu.ac.ir/browse.php?a_code=A-10-378-3&slc_lang=en&sid=1 Zahra Saghafi Z.saghafi@yahoo.com 10031947532846003321 10031947532846003321 No Department of Food Science and Technology, National Nutrition and Food Technology Research Institute. Faculty of Nutrition and Food Science. Shahid Beheshti University of Medical Sciences and Health Services Bahareh Nikooyeh nikooyeh11024@yahoo.com 10031947532846003322 10031947532846003322 No Laboratory of Nutrition Research, National Nutrition and Food Technology Research Institute and Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran Ali Jamali ajamalii2@gmail.com 10031947532846003323 10031947532846003323 No Quality control laboratory, Kourosh Food Industry (Tehran, Iran) Mercedeh Mehdizadeh Mer_mahdizadeh@yahoo.com 10031947532846003324 10031947532846003324 No Quality Assurances Unite, Kourosh Food Industry,Tehran, Iran Azizollaah Zargaraan aziz.zargaran@gmail.com 10031947532846003325 10031947532846003325 Yes Department of Food and Nutrition Policy and Planning Research, National Nutrition and Food Technology Research Institute. Faculty of Nutrition and Food Science. Shahid Beheshti University of Medical Sciences and Health Services