Calcium carbonate powder is simply calcium carbonate, the mineral in limestone and eggshells (INS 170(i), E170), supplied as a very fine white powder. The word “powder” describes the form it is added in: milled finely enough to blend evenly into flour and dough without any gritty feel. Food-grade powder is made by grinding purified limestone or by precipitating it from a calcium solution.
In biscuits it can play several roles. It is an inexpensive, concentrated source of calcium, about 40 percent calcium by weight, and it can also work as an acidity regulator or flour treatment agent. The label does not say which job it does in a particular recipe.
On SeekSnack it shows up across the Koala’s March range from Lotte, for example Koala’s March Chocolate and Koala’s March Strawberry, where it is listed among the biscuit ingredients right after egg.
