Tag: nixtamalization

Breaking Ground: Natalia Palacios gets the most out of maize

Written by Steven M on April 14, 2021. Posted in Features.

It’s often joked that specialists learn more and more about less and less until they know everything about nothing, while for generalists it’s just the opposite.

In the case of Natalia Palacios, neither applies. She may have the word specialist in her title — she is a maize quality specialist at the International Maize and Wheat Improvement Center (CIMMYT) — but throughout her career she has had to learn more and more about a growing range of topics.

As leader of the Nutrition Chapter of the Integrated Development Program and head of the Maize Quality Laboratory, Palacios’ job is to coordinate CIMMYT’s efforts to ensure that maize-based agri-food systems in low- and middle-income countries are as healthy and nutritious as possible. The scope of this work spans the breadth of maize-based agri-food systems — from seed to supper.

“What ultimately matters for human health and nutrition is the nutritional quality of the final product,” says Palacios. “High quality, nutritious grain is an important part of the puzzle, but so are the nutritional effects of various post-harvest storage, processing, and cooking techniques.”

Natalia Palacios (front, center) with colleagues on CIMMYT’s Quality Maize team during an Open House event at CIMMYT HQ. (Photo: Alfonso Cortés/CIMMYT)

Seeing the forest and the trees

Originally from Bogota, Colombia, Palacios studied microbiology at the Universidad de los Andes before pursuing a PhD in plant biology at the University of East Anglia and the John Innes Centre in the United Kingdom.

“I had the opportunity to work as research assistant at the International Center for Tropical Agriculture (CIAT) in Cali, Colombia,” she explains. “The exposure to interdisciplinary and international teams working for agricultural development and the leadership of my boss at that time, Joe Tohme, not only helped convince me to pursue post graduate studies in plant biology, they fostered an excitement around the real-world applications of scientific research.”

When she joined CIMMYT in 2005, Palacios worked on maize biofortification, supporting efforts to breed maize varieties rich in provitamin A and zinc. With time, she found her attention shifting towards the effect of food processing on the nutritional quality of maize-based food products, as well as to the importance of maize safety. For example, for a recent project, Palacios and her team have been analyzing the effect of a traditional thermal alkaline maize treatment known as nixtamalization on the physical composition of the grain and the nutritional quality of end products. Because of its important benefits, they are promoting this ancient technique in other geographies.

For Palacios, shifts such at this are completely in keeping with the overall goal of her work. “The main challenge we face as agricultural researchers is contributing to a nutritious, affordable diet produced within planetary boundaries,” she says. “Tackling any part of this challenge requires us to communicate between disciplines, to look at agri-food systems as a whole, and to link production and consumption.”

At the same time, for Palacios, the beauty of her work lies in going deep into a specific research question before bringing her focus back to the big picture. This movement between the specific and the general keeps her motivated, generates new questions and avenues of research, and keeps her from falling into silver-bullet thinking.

For example, her work on provitamin A biofortified maize led her to ask questions about how much of the vitamin reached consumers depending on how the grain was stored and handled. The vitamin is prone to degradation through oxidation. This led to storage and processing recommendations meant to maximize the crop’s nutritional value, including storing provitamin A maize as grain and milling it as late as possible before consumption. Researchers also worked to identify germplasm with more stable provitamin A carotenoids to be used in the breeding program.

In one study, Palacios and her coauthors found that feeding biofortified maize to hens increased the provitamin A value of their eggs, suggesting that for rural households the nutritional benefits of the improved grain could be spread out across different foodstuffs.

Natalia Palacios extracts carotenoids from maize kernels in a CIMMYT lab in Mexico. (Photo: Alfonso Cortés/CIMMYT)

Bringing it all together

In a paper published last spring, Palacios and her co-authors bring together the insights of these various avenues of research into one comprehensive review. The point, Palacios explains “was to identify opportunities to exploit the nutritional benefits of maize — a grain largely consumed in Africa, Latin America and some parts of Asia as important part of a diet — from understanding how to leverage the its genetic diversity for the development of more nutritious varieties to mapping all the different parts of the food system where nutritional gains can be made.”

The paper encompasses sections on the biochemistry of maize, maize breeding, maize-based foodways and culture, and traditional agronomic practices like milpa intercropping. It exemplifies Palacios’ interdisciplinary approach and her commitment to exploring multiple, interconnected pathways towards more nutritious maize agri-food systems.

As CGIAR’s 2030 Research and Innovation Strategy makes clear with its emphasis on the need for a systems-level transformation of food, land and water systems, this approach is timely and much needed.

In Palacios’ words: “Food security, nutrition and food safety are inextricably linked, and we must address them from the field to the plate and in a sustainable way.”

What is nixtamalization?

Written by Emma Orchardson on March 23, 2021. Posted in Explainers.

For centuries, people across Mexico and Central America have been using a traditional method, known as nixtamalization, to process their maize.

Now carried out both at household and industrial levels, this technique offers a range of nutritional and processing benefits. It could easily be adopted by farmers and consumers in other parts of the world.

What is nixtamalization?

Nixtamalization is a traditional maize preparation process in which dried kernels are cooked and steeped in an alkaline solution, usually water and food-grade lime (calcium hydroxide).

After that, the maize is drained and rinsed to remove the outer kernel cover (pericarp) and milled to produce dough that forms the base of numerous food products, including tortillas and tamales.

How does it work?

Key steps of the traditional nixtamalization process. (Graphic: Nancy Valtierra/CIMMYT)

What happens when maize kernels are nixtamalized?

The cooking (heat treatment) and steeping in the alkaline solution induce changes in the kernel structure, chemical composition, functional properties and nutritional value.

For example, the removal of the pericarp leads to a reduction in soluble fiber, while the lime cooking process leads to an increase in calcium content. The process also leads to partial starch gelatinization, partial protein denaturation — in which proteins present in the kernel become insoluble — and a partial decrease in phytic acid.

What are the benefits of processing maize in this way?

In addition to altering the smell, flavor and color of maize products, nixtamalization provides several nutritional benefits including:

Increased bioavailability of vitamin B3 niacin, which reduces the risk of pellagra disease
Increased calcium intake, due to its absorption by the kernels during the steeping process
Increased resistant starch content in food products, which serves as a source of dietary fiber
Significantly reduced presence of mycotoxins such as fumonisins and aflatoxins
Increased bioavailability of iron, which decreases the risk of anemia

These nutritional and health benefits are especially important in areas where maize is the dietary staple and the risk of aflatoxins is high, as removal of the pericarp is thought to help reduce aflatoxin contamination levels in maize kernels by up to 60% when a load is not highly contaminated.

Additionally, nixtamalization helps to control microbiological activity and thus increases the shelf life of processed maize food products, which generates income and market opportunities for agricultural communities in non-industrialized areas.

Where did the practice originate?

The word itself comes from the Aztec language Nahuatl, in which the word nextli means ashes and tamali means unformed maize dough.

Populations in Mexico and Central America have used this traditional maize processing method for centuries. Although heat treatments and soaking periods may vary between communities, the overall process remains largely unchanged.

Today nixtamalized flour is also produced industrially and it is estimated that more than 300 food products commonly consumed in Mexico alone are derived from nixtamalized maize.

Can farmers and consumers in other regions benefit from nixtamalization?

Nixtamalization can certainly be adapted and adopted by all consumers of maize, bringing nutritional benefits particularly to those living in areas with low dietary diversity.

Additionally, the partial removal of the pericarp can contribute to reduced intake of mycotoxins. Aflatoxin contamination is a problem in maize producing regions across the world, with countries as diverse as China, Guatemala and Kenya all suffering heavy maize production losses as a result. While training farmers in grain drying and storage techniques has a significant impact on reducing post-harvest losses, nixtamalization technology could also have the potential to prevent toxin contamination and significantly increase food safety when used appropriately.

If adapted, modern nixtamalization technology could also help increase the diversity of uses for maize in food products that combine other food sources like vegetables.

Cover photo: Guatemalan corn tortillas. (Photo: Marco Verch, CC BY 2.0 DE)

Women mill nixtamalized maize in Michoacan, Mexico. (Photo: Peter Lowe/CIMMYT)

Nixtamalization: An ingenious solution for healthier maize-based diets

Written by Steven M on December 21, 2020. Posted in Videos.

Some 500 years ago — in the wake of the cataclysmic encounter between European powers and the indigenous cultures of the Americas — people, ideas, goods and enormous amounts of biological material were sucked into an unprecedented planetary network of commercial circuits and flung around the globe. But the process was chaotic and often violent. People, ideas and other living things that had long commingled and coevolved were torn apart, and often sent hurtling down very different trajectories.

Among the many forms of plant life caught up in this global dispersion event was a curious grain developed over thousands of years in Mesoamerica: maize. Today it is the world’s most widely planted cereal crop — a cornerstone of the global industrial food system on the one hand and many local and regional agri-food systems on the other.

The thing is that to truly understand a crop you arguably must look beyond the plant itself and see it in relation to a variety of human agricultural, culinary and socioeconomic practices. But maize moved around the globe shorn of its complement of indigenous knowledge and practices. As a food archeologist Bill Schindler argues in a new video for Wired, this rupture has had enormous consequences for the health and well-being of maize-consuming communities up to the present.

The video, which borrows from an explainer produced by the International Maize and Wheat Improvement Center (CIMMYT), notes that for centuries maize producers and consumers in the Americas have processed maize using a technique called nixtamalization. This treatment — cooking and steeping dried maize kernels in an alkaline solution made with water and lime or wood ash — provides several nutritional and sanitary benefits, including: increased niacin and iron bioavailability, increased calcium and resistant starch content, and decreased mycotoxin contamination.

Maize-dependent diets that do not incorporate nixtamalization have historically contributed to outbreaks of pellagra and other nutrient deficiency-driven health problems. Today un-nixtamalized maize is used as the nutritionally-poor but chemically malleable basis for many hyper-processed foodstuffs thought to have contributed to the meteoric rise of diet-related disease since the 1980s.

Faced with this, Schindler asks: what if more of the world finally reunited maize with it’s indigenous processing techniques. Heat, water and lime — it might just be a solution to some pretty big problems.

Corn Fed: A Tortilla Revolution in Queens

Written by Mary Donovan on December 2, 2019. Posted in In the media.

Food entrepreneur Jorge Gaviria had the idea to small-scale farmers one by one who had surplus corn, buy it from them at market price and then import it to the United States. He partnered with CIMMYT to build up relationships with farmers, working out intricate systems that would determine fair prices and ensure that they were only buying surplus corn.

Kenyan maize nutrition and safety get boost from ancient Mexican technique

Written by on May 6, 2016. Posted in News.

A milling machine for preparing nixtamalized maize dough was presented to KALRO through the Mexican Embassy. Photo: B. Wawa/CIMMYT — A milling machine for preparing nixtamalized maize dough was presented to Kenya Agricultural & Livestock Research Organization by the Mexican embassy in Nairobi, Kenya. CIMMYT/Brenda Wawa

NAIROBI, Kenya (CIMMYT) — Although maize is a staple food for millions of Kenyans it is usually consumed in one of five ways: roasted or boiled; mixed with beans, or in ugali (a dough-like dish made from maize flour, millet flour or sorghum flour) and porridge. This is nothing compared to over 600 dishes derived from maize in Mexico, about 300 of them made through a process called nixtamalization or lime-cooking.

The process includes cooking and steeping dried maize grain in water and food-grade lime (calcium hydroxide), rinsing the maize to remove the outer kernel cover (pericarp) and milling it to produce dough that can be consumed in different ways, according to Natalia Palacios, maize quality specialist at the International Maize and Wheat Improvement Center (CIMMYT). This method, first developed in Mesoamerica where the crop was originally cultivated, has existed in the region for thousands of years.

If adapted, modern nixtamalization technology could increase maize uses and offer Kenyans invaluable benefits. Food-grade lime is rich in calcium, providing nutritional and health benefits. Nixtamalized food products such as tortillas (small circular-shaped flatbreads) are said to have same nutritional value as milk. About 94 percent of Mexicans eat tortillas, with 79 kilograms (174 pounds) per capita being consumed in rural areas and 57 kilograms per capita in urban areas every year.

By removing the pericarp, the technology contributes to reduce aflatoxin fungal contamination levels in maize kernels by 30 to 60 percent. Due to aflatoxins, Kenya has suffered maize production losses and, more importantly, a loss of human lives. In 2004, 124 people died due to aflatoxin contamination, and 155,000 90-kilogram bags of maize had to be discarded, according to government reports. Nixtamalization technology may therefore also contribute to increasing food safety for Kenyan consumers, who, according to the U.N. Food and Agriculture Organization, are not fully aware of the harvest, drying and storage techniques necessary to prevent mycotoxin growth and contamination.

Participants prepare tortillas from nixtamalized dough. Photo: B. Wawa/CIMMYT — Participants prepare tortillas from nixtamalized dough. Photo: CIMMYT/Brenda Wawa

The benefits of nixtamalization will soon become a reality for Kenyans following the official presentation of nixtamalized maize mills to the Cabinet Secretary of Kenya’s Ministry of Agriculture, Livestock and Fisheries by Mexico’s ambassador to Kenya, Erasmo Martínez, which took place on 4 April 2016 in Nairobi. This event marked the official launch of a new project titled “Expanding maize utilization as food and enhancing nutrition improved health and development in Kenya through processing technologies from Mexico,” which will contribute to disseminating new technology across the country. The three-year project will be led by the Kenya Agricultural Livestock and Research Organisation (KALRO).

The launch was followed by a week of training of 27 trainers from the public and private sectors led by CIMMYT and its collaborators from the tortilla industry in Mexico City and the National Autonomous University of Mexico. The training focused on building the capacity of partners who will be the major drivers of the commercialization of nixtamalized products.

“Geographically Mexico is very far from Kenya, but we want to bring a technology that is benefiting millions of people in Mexico every day, and it’s my hope that this will go beyond Kenya,” Martínez said, lauding this milestone. The Mexican embassy and the Mexican Agency for International Cooperation and Development played a crucial role in bringing the technology to Kenya.

“This technology is important because of its value addition to our food sector through reduction of aflatoxin exposure, increased market and income opportunities for youth and women, which will attract and improve their involvement in agribusiness,” said Sicily Kariuki, Cabinet Secretary for Public Service and Youth, who played a key role in the initial discussion on transferring this technology to Kenya.

KALRO will support raising awareness of the technology among small- and medium-sized companies, increasing their investment opportunities. KALRO is the custodian of the equipment donated by the Mexican government that is being used for training. CIMMYT will support this work by providing technical and capacity building expertise.

“We will help to evaluate and monitor grain quality besides developing resilient maize to ensure we have improved materials that fit the purpose of an efficient nixtamalization,” Palacios said. CIMMYT will also continue to collaborate with its partners on research aimed at finding further scientific evidence of the use of nixtamalization as a way of decreasing aflatoxin exposure.