E150d - Sulphite ammonia caramel

Sulphite ammonia caramel is Class IV caramel — made with both sulphite and ammonium compounds. The double treatment gives the caramel a strong negative charge, and that charge is what makes it behave differently from the other three classes.

A negatively charged colour stays dispersed in an acidic, phosphate-containing drink instead of clumping and settling. That is a precise description of cola, and Class IV is the caramel used in it. It is by a wide margin the most-produced caramel colour in the world, almost entirely on the back of the soft drinks industry.

Cola and other dark soft drinks (its dominant use), some spirits and liqueurs, sauces, confectionery, and baked goods.

Sulphite ammonia caramel is authorised in Great Britain as E 150d, in Group II — food colours authorised at quantum satis.

EFSA's 2011 re-evaluation set a group ADI of 300 mg per kg of body weight per day covering all four caramel classes, derived from a no-observed-adverse-effect level of 30 g/kg bw/day in 13-week rat studies. Class IV falls under that group figure rather than taking the reduced Class III value. The Panel concluded that anticipated dietary exposure may exceed the ADI for Classes I, III and IV.

Class IV caramel is the additive at the centre of the North American 4-MEI (4-methylimidazole) debate. 4-MEI is a by-product of ammonia-process caramels; the EFSA opinion considered the caramel by-products as part of its evaluation and set the group ADI on that basis.

EFSA reported that anticipated exposure may exceed the ADI for Class IV. Separately, the 4-MEI by-product of ammonia-process caramels has driven regulatory attention in California; the substance is not restricted on that basis in Great Britain.

• FSA Register of Food Additive Authorisations — E 150d
• EFSA (2011), Scientific Opinion on the re-evaluation of caramel colours (E 150 a,b,c,d)
• EFSA (2012), Refined exposure assessment for caramel colours (E 150a, c, d)