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Development of Laboratory Techniques to Mimic Industrial-Scale Nixtamalization¹

¹A contribution of the University of Nebraska Agriculture Research Division, Lincoln, NE 68583. Journal Series No. 14871. ²Former graduate research assistant and professor, respectively, Department of Food Science and Technology, University of Nebraska, Lincoln, NE 68583-0919. ³Professor, Department of Statistics, University of Nebraska, Lincoln, NE. ⁴Corresponding author. Fax: 402-472-1693. E-mail: djackson@unlnotes.unl.edu

A laboratory nixtamalization process was developed to imitate larger scale cooking/steeping conditions. Corn (45 kg) was cooked in a pilot plant gas-fired cook/steep tank and temperature was monitored every 30 sec. Cooling and heating rates were mimicked in the laboratory using a digital temperature programmable hot plate that adjusted grain-water-lime temperature changes at a specified rate. A Response Surface Central Composite Design was used to model pasting and thermal properties of nixtamal and masa as a function of cooking temperature (86–96°C), cooking time (20–40 min), and steeping time (3–11.77 hr). Nixtamal and masa moisture, dry matter loss, nixtamal and masa RVA peak temperature, shear thinning, nixtamal peak viscosity, masa final viscosity, nixtamal and masa DSC enthalpy peak and end temperatures, and nixtamal onset temperature were explained by the same regression terms for results obtained using both processes conditions. The intercept and slopes of the fitted models for the pilot plant and laboratory responses were not significantly different (P < 0.05). The laboratory method can be used to mimic larger scale processing over a wide range of nixtamalization conditions.