Masa and nixtamalization
Tortilla corn is simmered and soaked in water with calcium hydroxide, a mineral called cal or slaked lime. It has nothing to do with citrus. The alkali loosens the hulls, softens the kernels and frees niacin locked in raw corn.
From kernel to dough
After soaking, the corn is rinsed to remove loosened hulls and extra alkali, then ground wet into masa. Plain cornmeal skips all that, so it crumbles when pressed. Masa harina is dried masa that just needs water.
Test yourself
Questions from the interactive lesson, with the answer and the why.
What is the lime used in nixtamalization?
Calcium hydroxide, an alkaline mineral. This alkali breaks down the hulls and changes the corn.
True or false: Masa holds together because corn contains gluten like wheat does.
False. Corn has no gluten, and alkali-treated starch and protein are what make masa hold together.
What went wrong? You stir plain cornmeal and water into a dough for tortillas. The pressed rounds crack into crumbs.
Plain cornmeal was never treated, so it doesn't bind. Untreated corn flour lacks the changes that make masa hold together.
Fill the blank: Soaking corn in an ___ solution loosens its hulls.
Soaking corn in an alkaline solution loosens its hulls. Calcium hydroxide is an alkali, and it breaks down the hulls.
Which change from nixtamalization explains why masa sticks together?
The starch and protein change, so ground corn binds. Alkali treatment makes the ground corn pliable and sticky.
True or false: Nixtamalization frees niacin that is bound in raw corn.
True. The alkali releases niacin that is locked inside the kernel.