ABSTRACT
Maize kernels, calcium hydroxide and water are the three basic raw materials used for the production of fresh masa or alternatively dry masa flour (DMF) used for the production of corn and tortilla chips. The lime-cooked maize, named nixtamal, is normally stone-ground into a masa suitable for the manufacturing of these deep-fat fried snacks, which are considered as the second most important category of savory snacks in terms of volume and sales. Oil, salt, and flavorings are intentionally added to modify flavor, mouth feel and improve sensory attributes of these snacks. The industrial processes consist of cooking maize kernels in a lime solution to produce nixtamal, which is washed to remove excess lime and then ground into a masa. The masa can be dehydrated and reground to produce DMF for different applications. Fresh or reconstituted masa from DMF is formed into different configurations and fried in order to produce corn chips or first baked in continuous ovens and then deep-fat fried to produce the more popular tortilla chips. Industrial production of DMF is accomplished by lime-cooking, washing, nixtamal grinding, drying, sieving, regrinding coarse particles, resieving, classifying, and blending to meet certain requirements especially in terms of starch gelatinization and granulation. The DMF is reconstituted into masa by simply blending with water for a few minutes. Alternatively, processors are increasingly manufacturing light and low-fat tortilla chips using additional baking/toasting with impingement ovens to suit the growing market of health-conscious customers. Emerging technologies have been developed to cook masa and produce the snacks from fresh masa or DMF. The most promising are extrusion cooking, low-shear laminar cooking, Ohmic heating, microwaving, ultrasound/cavitation, and infrared cooking. This chapter reviews regular and emerging technologies currently used for the production of lime-cooked products, mainly corn and tortilla chips.
