Influence of light exposure and oxidative status on the stability of vitamins A and D-3 during the storage of fortified soybean oil

Food fortification is implemented to address vitamins A and D deficiencies in numerous countries. The stability of vitamins A and D-3 was assessed during a two-month period reproducing the usual oil storage conditions before sale to consumers. Soybean oils with different oxidative status and vitamin E contents were stored in the dark, semi-dark, or exposed to natural light. Lipid peroxidation took place after 3 weeks of storage in dark conditions. After 2 months, the vitamin A and D-3 losses reached 60-68% and 61-68%, respectively, for oils exposed to natural light, and 32-39% and 24-44% in semi-dark conditions. The determining factors of vitamin A and D-3 losses were (in decreasing order) the storage time, the exposure to light and the oxidative status of the oil, whereas vitamin E content had a protective role. Improving these parameters is thus essential to make vitamins A and D fortification in oils more efficient.