Date Published: June 30, 2017
Publisher: Tabriz University of Medical Sciences
Author(s): Mehrnaz Tabibian, Mohammadali Torbati, Mohammad Reza Afshar Mogaddam, Maryam Mirlohi, Malihe Sadeghi, Javad Mohtadinia.
Purpose: Vitamin D, a fat-soluble secosteroid, has a significant role in bone metabolism and helps calcium absorption in the body. Since vitamin D concentration is altered in fortified foods and dietary supplements, the actual amount of vitamin D may differ from the label value.
Vitamins are essential for the health of humans and animals and cannot be synthesized by these vertebrates. Therefore, they must be obtained from the diet. Generally, vitamins are classified into categories named fat-soluble or water-soluble according to their solubilities in solvents.1 Fat-soluble vitamins are composed of four vitamins namely A, E, D, and K.2 Among these compounds vitamin D has a key role in human health. Vitamin D deficiency is known as a major hidden health problem worldwide. During recent years there has been increasing evidence indicates that vitamin D may contribute to the pathogenesis of multiple sclerosis and influence the disease course and activity.3 On the other hand, excessive vitamin D intake is associated with the risk of hypercalcaemia or hypercalciuria and kidney problems.4,5 Human obtains his vitamin D needs in two forms including vitamins D3 (cholecalciferol) and D2 (ergocalciferol) from two sources. Cholecalciferol is biosynthesized in the skin during exposure to UV light, whereas ergocalciferol is absorbed from the diet.6 Although animal originated foods are traditionally supplemented by excess level of vitamin D3, fortifying different foods has recently been considered. One of the most important foods is bread.7 Bread is a main food prepared from the dough of flour and water, typically by baking. In some bread, non-cereal materials including nuts, fats and vitamins are added to improve the nutritional value due to high consumption of it in different meals.8-10 After fortification, the most crucial parameter is the stability of the added materials in different procedures. Vitamin D stability in fortification regimes has been investigated in milk, yogurt and cheese.11-13 The obtained results indicate that vitamin D stability in pure form decreases by heating to 150 °C in the presence of air. On the other hand, in acidic media vitamin D might be isomerised to isotachysterol. Similar to these products vitamin D can be altered in bread samples during dough fermentation, baking, and storage which should be considered.14-16
In the present work, the stability of vitamin D3 and D2 has been studied in bread samples in different conditions. The obtained results showed that the added vitamins’ level was decreased at the fermentation time higher than 60 min. However, the added vitamins are stable at different temperatures in this step. Baking the dough at high temperatures led to decrease in vitamin levels. Also, vitamin D3 and D2 levels in stale bread were less than fresh bread.
Authors present their appreciation to the Tabriz University of Medical Sciences for their financial support of this project (No. 40/A/93/8/15).
The authors declare no conflict of interests.