Tocopherols
Seven closely related tocopherol compounds are known to occur in nature; they are identified by the prefix alpha, beta, gamma, delta, etc.
Tocopherols are the most widely distributed antioxidants in nature, and are the principal antioxidants in vegetable oils. Small amounts may be detected in animal fats, originating from the vegetable components of the animal’s diets.
As a result of their long alkyl chain, tocopherol are fat soluble, and are easily dispersed in fats and oil.
Vitamin E physiological activity decreases from alpha to delta homologs, while antioxidant activity increases in this order.
All naturally occurring tocopherols occur in the D form, whereas synthetic tocopherols contain a 50/50 mixture of the D and L isomers.
Synthetic D,L-alpha-tocopherol is marketed as an acetate ester for its increase stability to light and air. The physiological activity of D,L-alpha-tocopherol acetate, D,L-alpha-tocopherol, D-alpha-tocopherol acetate and D-alpha-tocopherol is 1.0, 1.1, 1.36 and 1.49 IU/mg, respectively.
Naturally occurring tocopherols are easily oxidized under adverse conditions. Tocopherols are heat sensitive and thus may be lost during processing operations.
Tocopherols functions as free-radical chain terminators by donating hydrogen atoms to free radicals, subsequently becoming oxidized to their corresponding quinone forms.
Tocopherols exert their greatest effect in protection of animals fats (such as tallow) carotenoids, and vitamin A. Tocopherols also functions as antioxidants in bacon, baked goods, butterfat, lard, margarine, rapeseed oil, safflower oil, and sunflower seed oil.
Tocopherols
