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The new Bühler process for manufacturing nixtamal corn flour for tortillas and tortilla chips by Alexandra Londoño Baderschneider, Product Manager, Bühler

inety percent less water, no investment in wastewater treatment, higher yield, lower maintenance and a high degree of automation: the new Bühler process for manufacturing nixtamal corn flour for tortillas and tortilla chips meets the highest expectations. Tortillas and tortilla chips made from nixtamal corn flour are a firm feature on the menu in all Central American countries. Already the Aztecs made and ate corn tortillas. It is hard to imagine the American cuisine nowadays without them. In North and Central America, more than 13 million tonnes of corn are processed each year to produce nixtamal corn flour. Corn tortillas have also conquered eating habits in other regions of the world. Tortilla chips have actually made their mark throughout the world; currently more than 1.3 million tonnes are consumed worldwide.

Nixtamal

Corn was originally cooked on a fire. In Central America, ash was also added to the corn when cooking as a flavor carrier. The ash provided the special flavor, which is also characteristic of tortillas and tortilla chips made of nixtamal corn flour today. The nixtamal description for the new Bühler process for manufacturing nixtamal corn flour derives from the two Aztec words ‘nixt’ and ‘damalli’ or ‘ash’ and ‘cooked corn’.

Energy-intensive

Corn tortillas and tortilla chips are made from specially treated nixtamal corn flour. In traditional production the corn is cooked for several hours in water and burnt lime is added before grinding. The nixtamal corn flour treated in this way gives the finished tortillas and tortilla chips their typical lime flavor. For the industrial production of tortilla flour, a great deal of water is therefore used – around 1500 litres for 1000 kilograms of corn processed into nixtamal corn flour. The added lime also 74 | August 2017 - Milling and Grain

contaminates this large volume of cooking water, which requires expensive reprocessing equipment to clean the wastewater.

Environmentally friendly solution sought

In 2010, Bühler began to develop an environmentally friendly manufacturing process for nixtamal corn flour for tortillas. In the new process, the corn is no longer cooked but simply steamed. The “Prime Masa Nixtamal” process therefore uses around 90 per cent less water. Nor is any wastewater produced in this way, which makes expensive reprocessing equipment superfluous. Nevertheless, the Prime Masa process enables the production of tortilla flour with its typical flavor, as well as high quality and yield.

The nixtamal process

The Bühler process for the environmentally friendly production of tortilla flour is similar to that for manufacturing cereal flakes. The corn kernels are cleaned after intake. The corn kernels are conditioned for preparation. To do this, the corn grits are moistened with limewater and finally steamed in the steamer that is central to the nixtamal process stage. After steaming, the corn grits are flaked on the flaking roller mill, then cooled and dried. The resulting corn flakes are finally ground into fine nixtamal corn flour, which is enriched accordingly with iron, vitamins or other ingredients as required by the consumer. This is then made into dough by adding water, to be processed into tortillas and tortilla chips.

AUG 2017 - Milling and Grain magazine