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Alkaline Processing (Nixtamalization) of White Mexican Corn Hybrids for Tortilla Production: Significance of Corn Physicochemical Characteristics and Process Conditions¹

¹Journal Series No. 12844, Agricultural Research Division, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln. ²Research associate, research associate, research associate, research technician, research technician, and associate professor, respectively, Cereal/Oilseed Science and Technology Laboratory, Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE 68583. ³Corresponding author. Phone: 402-472-2814; Fax: 402-472-1693; E-mail: djackson@unlnotes.unl.edu

Five white corn hybrids were processed (nixtamalized) using 10 different processing conditions; tortillas were prepared to establish relationships between corn composition, physical characteristics, and nixtamalization process or product properties. Corn hybrids were characterized by proximate analysis and by measuring Stenvert hardness, Wisconsin breakage, percent floaters, TADD overs, thousand-kernel weight, and test weight. Corn characteristics were correlated with process and product variables (effluent dry matter loss and pH; nixtamal moisture and color; masa moisture, color, and texture; and tortilla moisture, color, and rollability). Process and product variables such as corn solid loss, nixtamal moisture, masa texture, and tortilla color were influenced not only by processing parameters (cook temperature, cook time, and steep time) but also depended on corn characteristics. Significant regression equations were developed for nixtamalization dry matter loss (P < 0.05, r² = 0.79), nixtamal moisture (P < 0.05, r² = 0.78), masa gumminess (P < 0.05, r² = 0.78), tortilla texture (P < 0.05, r² = 0.77), tortilla moisture (P < 0.05, r² = 0.80), tortilla calcium (P < 0.05, r² = 0.93), and tortilla color a value (P < 0.05, r² = 0.87).