Mina Esmaeili
1,2 
, Reza Yekta
3,2 , Abdol-Samad Abedi
4,2, Kiandokht Ghanati
2,5, Robabe Zamani Derav
6, Anahita Houshyarrad
1,2 , Zeinab Saberi Dehkordi
7, Marjan Ajami
8,2* , Maryam Mahmoudzadeh
9,10,111 Department of Nutrition Research, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
2 National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
3 Student Research Committee, Department of Food Science and Technology, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
4 Department of Research Deputy, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
5 Research and Education Affairs Office of International Affairs, Food Safety Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
6 Hepatology and Nutrition Research Center, Research Institute for Children’s Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
7 Department of Chemistry, Isfahan University of Technology, Isfahan, Iran.
8 Department of Food and Nutrition Policy and Planning Research, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
9 Drug Applied Research Center and Nutrition Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
10 Nutrition Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
11 Department of Food Science and Technology, Faculty of Nutrition and Food Science, Tabriz University of Medical Sciences, Tabriz, Iran.
Abstract
Vitamin D (VD) deficiency is a significant issue affecting a large population around the world. As its natural sources are limited, people must constantly fortify their VD. Encapsulating VD increases its bioavailability and stability during processing and storage; hence it has promising potential to avoid VD deficiency. This study reviews current methods of VD fortification and encapsulation. Two predominant methods of VD fortification, i.e., biofortification and direct fortification, are advantageous over VD supplementation. However, significant VD losses occur during processing, storage, and passing across the stomach which can be minimized through encapsulation methods, i.e., micro and nanoencapsulation. Moreover, the capsule features like size, wall-to-core ratio, wall material, carrier oil composition, and encapsulation technique significantly affect VD bioavailability. To assess the optimum encapsulation procedures and possible risks in food fortification, comprehensive in vitro and in vivo studies must be conducted. Depending on the staple food products of a specific region, both VD fortification strategies have great potential in different countries. Besides, the risk of VD overdose due to fortifying a single staple food product is higher than fortifying various staple food products.