The ancient process of nixtamalization was first developed in Mesoamerica, where maize was originally cultivated. There is no precise date when the technology was developed, but the earliest evidence of nixtamalization is found in Guatemala's southern coast, with equipment dating from 1200–1500 BCE.
The ancient Aztec and Mayan civilizations developed nixtamalization using lime (calcium hydroxide) and ash (potassium hydroxide) to create alkaline solutions.
The first step in nixtamalization, kernels of dried maize are cooked in an alkaline solution at or near its boiling point. After cooking, the maize is steeped in the cooking liquid for a certain period of time.
During cooking and soaking, a number of chemical changes take place. The grain hydrates and absorbs calcium or potassium from the cooking solution. Starches swell and gelatinize. Certain chemicals from the germ are released that allow the cooked grains to be ground more easily, making the dough less likely to tear and break. Cooking changes the grain's protein matrix, which makes proteins and nutrients from the endosperm of the kernel more available to the human body.The prepared grain is called nixtamal.