University of Nebraska–Lincoln

The Food Processing Center

From Imagination to Market

Tortilla and Snack Processing

Corn and Wheat Flour Tortillas
Tortilla and Corn Chips
Related Evaluation and Analytical Services

(Download our brochure in PDF - Adobe Acrobat Format)

Our capabilities include pilot-plant processing of corn (traditional whole-kernel or masa flour) and wheat flour tortillas (hot-press), tortilla chips, corn chips, and related snacks and flat-breads. Post-process analyses procedures include shelf-life evaluation (texture and microbiological safety) and starch properties.

Processing Methods and Capabilities

David S. Jackson, Ph.D.

Professor

402-472-2814
Contact

Focus Areas:
  • Starch Analysis
  • Grain Testing
  • Grain Processing
  • Tortilla Production
  • Extrusion Processing
  • Ingredient Functionality
  • Product Development
Traditional Whole-Kernel Corn Cooking for Production of Tortillas, Tortilla Chips and Corn Chips

Gas-fired cook/steep tank

Corn is cooked and steeped in this gas-fired temperature controlled nixtamilzation tank. Cook and steep times are varied according to corn properties and desired end-product characteristics. After steeping, the corn is washed to remove excess lime and pericarp. Washing can be accomplished using manual washing in the tank or automated using our commercial spray-nozzle washing system (not shown).

Masa Grinder

Washed cooked/steeped corn (nixtamal) is stone ground to form masa. Masa is the dough used to produce tortillas, tortilla chips, corn chips and similar products.

An Alternate Process:
Instant Masa Flour

Many manufacturers, instead of investing in the equipment required for traditional nixtamalization, use instant masa flour. Instant masa flour is typically prepared in large facilities and shipped to tortilla/snack/taco-shell manufactureres. These manufactureres simply hydrate the flour to produce masa. We have capabilities of producing limited quantities of instant masa flour or we can use commercial masa flour.

Commercial flours come in a variety of particle sizes, colors, etc. Several manufacturerers produce products with gum and antimivrobial agents already added. Our testing facilities allow for ingredient manufactuers to test their anti-staling and anti-microbial agents for effectiveness.

Sheeter and Baking Oven

Two rolls compress the masa dough into a thin sheet; we have cutters that produce round tortillas or triangular tortilla chips.

The baking oven is a three-tiered gas oven (model 0P01004-07 Micro Combo) from Lawrence Equipment Co.

Cooling Rack and Product Inspection

Tortillas (or chips), after exiting the oven, travel on a three-tier cooling rack prior to packaging and/or analysis.

Wheat Flour Tortilla Production

Small-Batch Dough Preparation

Besides much larger quantities, we can prepare wheat flour tortillas in small 1 kg batches. This allows for manufacturers to evaluate different flour types, ingredient levels, and ingredient functionality of various gums, antimicrobial agents, shortenings, etc.

Dividing and Rounding

After the wheat flour dough is prepared, a divider-rounder is used to prepare dough-balls suitable for hot-pressing into tortillas.

Dough Placement for Hot-Pressing

Dough Balls are pressed between two hot plates to produce tortillas ready for baking.

Baking

Tortillas are baked in the same gas fired oven used for corn tortillas; adjustments are made for appropriate bake time, toast marks, etc. Glass doors allow us to evaluate tortilla puffing during baking (an important quality attribute).

Cooling

Tortillas, after exiting the oven, travel on a three-tier cooling rack prior to packaging and/or analysis.

Evaluation Services

We specialize in evaluating corn, flour, minor ingredients and process conditions for all of the products we produce in our pilot plant.

Our routine post-production analyses including various tortilla quality tests (rollability, flexibility, visible mold growth, etc.) performed during storage. Our services can also include highly objective texture testing using a Texture Analyzer and sophisticated starch testing.

Selected Publications on Tortillas, Snacks and Alkaline Processing/Nixtamalization

Guo, G., Jackson, D.S., Graybosch, R.A., and Parkhurst, A.M. 2003. Wheat tortilla quality: Impact of amylose content adjustments using waxy wheat flour. Cereal Chem. 80(4):427-445.

Sahai, D. and Jackson, D.S. 2001. A novel enzymatic nixtamalization process for producing corn masa flour. Cereal Foods World: 46:240-246.

Sahai, D., Buendia, M.O. and Jackson, D.S. 2001. Analytical Techniques For Understanding Nixtamalized Corn Flour: Particle Size and Functionality Relationships in a Masa Flour Sample. Cereal Chem. 78(1):14-18.

Sahai, D., Mua, J.P., Surjewan, I., Buendia, M.O., Rowe, M. and Jackson, D.S. 2001. Alkaline processing (Nixtamalization) of white mexican corn hybrids for tortilla production: Significance of corn physico-chemical characteristics and process conditions. Cereal Chem. 78(2):116-120..

Sahai, D., Surjewan, I., Mua, J.P., Buendia, M.O., Rowe, M., and Jackson, D.S. 2000. Dry matter loss during nixtamalization of a white corn hybrid: Impact of processing parameters. Cereal Chem. 77(2):254-258.

Sahai, D. Mua, J.P., Surjewan, I., Buendia, M.O., Rowe, M. and Jackson, D.S. 1999. Assessing degree of cook during corn nixtamalization: Impact of processing variables. Cereal Chem. 76:850-854.

Shandera, D.L., Jackson, D.S. and Johnson, B.E. 1997. Quality factors impacting processing of maize dent hybrids. Maydica 42:281-289.

D.S. Jackson, L.W. Rooney, O.R. Kunze, and R.D. Waniska. 1988. Alkaline processing properties of stress-cracked and broken corn (Zea Mays L.). Cereal Chemistry 65(2):133-137.