Behavior of Tocopherol and Vitamin K1 in the Hydrogenation of Edible Oil

Determination was made of α-and γ-tocopherol, vitamin K1 and 2',3'-dihydrovitamin K1 in vegetable oil during the course of hydrogenation under various conditions. Iodine value(IV) was found to decrease from 80 to 60 with hydrogenation, with consequently considerable reduction in vitamin K1. At IV 50 or less, vitamin K1was virtually essentially absent (0.1 mg/kg or less). 2',3'-dihydrovitamin K1 increased with decrease in vitamin K1. 2',3'-dihydrovitamin K1 peaked at 2.9 mg/kg at IV 50, and then decreased. α-and γ-Tocopherol content remained basically the same under all conditions. Subsequent to oil hydrogenation and then deodorization at 260°C for 120 minutes, α-tocopherol showed the highest residual ratio (80%) of all the vitamins, followed by 2',3'-dihydrovitamin K1 (66%) and vitamin K1 (60%).