Which mineral is traditionally used as the alkaline agent in nixtamalization?

Which mineral is traditionally used as the alkaline agent in nixtamalization? Calcium hydroxide.

Calcium hydroxide, commonly called slaked lime or cal, is traditionally dissolved in water to make the alkaline solution used for nixtamalization. Corn is cooked and soaked in this limewater, then washed and hulled before being ground into masa.

The alkali breaks down hemicellulose in the corn’s outer layers, allowing the pericarp to loosen. Calcium also interacts with components of the grain and can increase the calcium content of the finished food. These chemical changes help produce dough that holds together for tortillas instead of crumbling like ordinary ground corn.

Calcium hydroxide should not be confused with limestone, which is mainly calcium carbonate, although limestone can be processed into lime. Ash and other alkaline substances have also been used in different regions, so lime is traditional rather than absolutely universal. In food labels, the ingredient may simply appear as “lime” or “treated with lime.”