You can read the basic info about all the caramel colors from this post:  https://sulfitesabc.com/e150b-caustic-sulfite-caramel-color/

This food preservative, E150d is the one which is used in many soft drinks, and as its name says it does contain sulfites. This caramel color is not only added to the drinks because of the obvious reason for coloring the water, but because the sulfite compounds in it makes it also a good emulsifier and a preservative which prevents oxidation of the flavouring components.

A question what pops up often with sulfites is that: “Can I drink colas anymore ? The answer is no, if you want to avoid also the trace amounts of sulfites. Sulfites tend to accumulate in the body, so having a glass of cola only once in awhile might not alone make you sick, but if you get some other hidden sulfites from other sources, your daily limit might get full pretty fast.  Most colas do not label the sulfites, since the amounts are often trace amounts and under 10 ppm. But that is for a serving size, and by now you should know how clever food companies can be when they label sulfites/don’t label them and even though some companies do label also the trace amounts, most don’t label anything under the limit of 10 ppm.

Food uses of Sulfite Ammonia Caramel Color:

• Cola drinks