became a staple among the poor of the southern states. This led to endemic pellagra in poor populations throughout the southern US in the early 20th century. A more varied diet and fortification of wheat flour, the other staple food, have essentially eliminated this deficiency. Process Cooking In the first step of nixtamalization, kernels of dried maize are cooked in an alkaline solution at or near the mixture's boiling point. After cooking, the maize is steeped in the cooking liquid for a period. The length of time for which the maize is boiled and soaked varies according to local traditions and the type of food being prepared, with cooking times ranging from a few minutes to an hour, and soaking times from a few minutes to about a day. During cooking and soaking, a number of chemical changes take place in the grains of maize. Because plant cell wall components, including hemicellulose and pectin, are highly soluble in alkaline solutions, the kernels soften and their pericarps (hulls) loosen. The grain hydrates and absorbs calcium or potassium (depending on the alkali used) from the cooking solution. Starches swell and gelatinize, and some starches disperse into the liquid. Certain chemicals from the germ are released that allow the cooked grains to be ground more easily, yet make dough made from the grains less likely to tear and break down. Cooking changes the grain's protein matrix, which makes proteins and nutrients from the endosperm of the kernel more available to the human body. Extraction After cooking, the alkaline liquid (known as nejayote), containing dissolved hull, starch, and other corn matter, is decanted and discarded (or sometimes used for making amate bark paper). The kernels are washed thoroughly of remaining nejayote, which has an unpleasant flavor. The pericarp is then removed, leaving the endosperm of the grain with or without the germ, depending on the process. This hulling is performed by hand, in traditional or very small-scale preparation, or mechanically, in larger scale or industrial production. The prepared grain is called hominy or nixtamal. Nixtamal has many uses, contemporary and historic. Whole nixtamal may be used fresh or dried for later use. Whole nixtamal is used in the preparation of pozole, menudo, and other foods. Ground fresh nixtamal is made into masa (nixtamal dough) and used to make tortillas, tamales, and arepas. Dried and ground, it is called masa harina or instant masa flour,