Secrets of Cal Cuisine

The corn tortilla has become a basic American bread that offers valuable nutrients. Unlike the flour tortilla, it contains no added fat and no wheat, and therefore it is gluten-free.

Whether made with masa flour or dried corn, tortillas are a good source of calcium, says Lloyd W. Rooney, professor of food science and technology at Texas A&M; University and head of the university’s cereal quality laboratories. The calcium is contributed by the lime, known as cal in Spanish, with which the corn is cooked. This white powder consists principally of calcium hydroxide with a small amount of magnesium oxide.

Adding lime reduces the cooking time required to remove the tough corn hulls.

“The lime penetrates inside the kernel, partially dissolves cell walls and changes starch and proteins, which allows subsequent grinding to produce masa which is able to hold together and be sheeted into a tortilla,” Rooney explains. During this process, calcium molecules are mixed into the masa.

“In addition, the lime makes the niacin in corn available to humans. Some desirable nutritional changes occur in proteins as well,” he says.