Tortilla production is a source of water pollution in Mexico
Credit: Verónica Díaz Favela/IPS
Scientists Reinvent the Corn Tortilla
By Verónica Díaz Favela
Mexican scientists are working to make
"nixtamalization," the ancestral technique for preparing maize to
be made into tortillas, a more environmentally sustainable process.
MEXICO CITY, Mar 1 (Tierramérica).- The process for making corn tortillas, the tasty and
millennia-old food for much of Mexico and Central America,
contaminates huge volumes of water and consumes a great deal
"Some years ago, a group of millers came to ask us if we had
done anything in this area, and we realized that with thousands
of mills in the country, the problem was big and something
should be done," Gerardo Ramírez Romero, researcher at the
biotechnology department of the Autonomous Metropolitan
University of Mexico (UAM), told Tierramérica.
That is how the study, "Nixtamal Mills: Towards a Sustainable
Corn tortillas are consumed by people of all socioeconomic
levels in Mexico and, like bread, accompanies nearly every meal.
It is also the basis for tacos, a popular dish.
At the mill, the maize is cooked in limewater, a calcium
hydroxide solution, and then ground to make the dough for
tortillas. The process, nixtamalization, was developed by
indigenous peoples of the pre-Hispanic era.
To make the tortilla, about 30 grams of the dough are made into
a ball, then rolled out to form a circle, approximately 14
centimeters in diameter. It is then cooked on a hot surface on
Cooking the maize in limewater produces a byproduct that is
rich in starch, cellulose and calcium, a mix known as nejayote,
and dumped directly down the drain, said Ramírez Romero.
Every kilogram of maize uses two liters of water. And a small
mill can contaminate 1,000 liters of water each day. There are
20,000 of these mills in Mexico.
In the first phase of the UAM study - which lasted three months
- the experts were able to reduce water contamination 80
percent, by removing the solids and producing more dough with
The next step will be to use solar energy to heat the water in
which the maize is boiled, as a means of reducing consumption
of natural gas, said Juan José Ambriz García, head of UAM's
department of engineering processes and hydraulics.
But the sun barely heats the water to 50 degrees Celsius, and
the maize cooks at 90 degrees. The temporary solution is to
pre-heat the water with solar energy and then make up the
difference using gas, Ambriz told Tierramérica.
This way, the mills would be able to save 40 percent on gas.
In the future, changes in the design of the cooking process itself
will make it unnecessary to reach 90 degrees, he said.
For now, solar energy is only being used to heat the mill water
in the laboratory. What is needed is to develop machinery that is
within the means of the tortilla producers and also allows them
to save electricity - and that could take several years.
Currently, the largest cost to the mills, after the maize itself, is
energy. A mid-sized mill - that provides dough to 10 tortilla
factories - spends some 2,300 dollars a month on energy.
Ideally, this technology would be distributed through the "Mi
Tortilla" program, created by the federal government for millers
to acquire new machinery, said Ambriz.
This type of mill "is a technological contribution from Mexico to
the world," he said. "What is critical is that they were left as they
were 100 years ago."
In the past, the mills were subsidized by the government,
pointed out Yolanda Hernández Franco, an anthropologist at
UAM. In the 1990s, the mills still received maize, gas, electricity
and water at reduced prices.
The tortilla factories and the mills received frequent visits from
inspectors in that period, but what they were doing was
collecting bribes, she said.
When the subsidies for the tortilla industry ended, the
inspectors and the corruption disappeared, but the millers were
left "facing a globalized world," not knowing how to operate
more efficiently, said the anthropologist.
"If the pollution regulations were applied, no mill would survive,"
In the first phase of the study, the focus was on mills in the
capital, but the next phase will encompass mills in different
parts of the country.
The mills tend to be family operations, passed down from
generation to generation, providing the dough to a group of
tortilla factories, usually belonging to the same person. The
largest mills supply more than 20 factories.
The mills themselves usually also have their own tortilla factory.
People wait their turn to buy their daily tortillas for less than a
dollar per kilo.
According to a survey of the maize flour producer Gruma,
Mexico's 107 million inhabitants each consume 80 kilos of
tortilla per year. There is no precise information on daily family
consumption, but it is believed to have fallen 25 to 30 percent in
recent years, due to increasing prices and families moving away
from the traditional Mexican diet.
Felipe Galindo owns a mill. He began working there when he was
10 years old, sweeping the floors. Thirty-five years ago, the mill
supplied 25 tortilla factories with dough - now it's just three, he
Galindo believes the decline is the result of the perception that
tortillas are fattening, even though "they have fewer calories
than a slice of bread."
According to Ambriz, "the tortilla is an excellent food," and "in
the pre-Hispanic combination of greens or protein of some
kind, including insects, it's an excellent diet."