dl-alpha-Tocopherol is the synthetic form of alpha-tocopherol, the main type of vitamin E. Chemical synthesis produces an equal mixture of eight closely related forms (stereoisomers), whereas plants make only one of them, d-alpha-tocopherol (INS 307a). The “dl” in the name signals this synthetic mixture. In the EU it is E307, and Codex lists it as an antioxidant.
In food it is used in small amounts to slow the oxidation of fats, keeping biscuits and fillings from tasting stale or rancid. It is often combined with ascorbyl palmitate (INS 304), which can regenerate it after it has reacted. Both are listed in Arnott’s Good Time Classic Chocochips Cookies and the Double Choc version, whose doughs are rich in vegetable fat and chocolate chips.
