E170 is calcium carbonate (INS 170(i)), the white mineral found in chalk, limestone and eggshells. When a label lists it as “Anticaking Agent (E170)”, the maker is using its ability to keep powdered ingredients such as sugar, starch or dry mixes from taking up moisture and sticking together, so they flow and blend evenly during production.
Food-grade calcium carbonate is either ground from purified limestone or made as a fine “precipitated” powder. It has practically no taste at the levels used. Anticaking is only one of its jobs: Codex also lists it as an acidity regulator, colour, firming agent, flour treatment agent and stabilizer, and it adds a little calcium.
On SeekSnack it appears in this role in the Shoei Tokyo Sweet Banana Gift Box, a banana cake from Japan.
