E306 (INS 306) is a tocopherol-rich extract: a mixture of the natural forms of vitamin E, the alpha, beta, gamma and delta tocopherols, concentrated from vegetable oils such as soybean or sunflower oil during refining. Tocopherols protect fats by reacting with oxygen first, so the oil in a cake or biscuit stays fresh for longer.
Because it is fat-soluble and comes from plant oils, E306 is a popular choice when a maker wants an antioxidant of familiar origin. It is approved for food use in the EU and permitted under Codex. The amounts are small: it is there to protect the product, not to act as a vitamin supplement.
Tocopherols made from soybean oil are highly refined, and EU allergen rules exempt them from soy labelling. On SeekSnack, Antioxidant (E306) is listed on the Shoei Tokyo Sweet Banana Gift Box, next to Color (E160a).
