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Methods to Evaluate Hydration and Mixing Properties of Nixtamalized Corn Flours

¹Graduate student, research scientist, and professor, respectively, Cereal Quality Laboratory, Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77843-2474. ²Corresponding author. Phone: 409/845-2925. E-mail: r-lobeira@tamu.edu

Rapid ViscoAnalyser (RVA), consistometer, and mixograph methods were developed to evaluate the pasting, hydration, and mixing characteristics of commercial nixtamalized corn flours (NCF) used for masa production. The effect of moisture level (51–58%) on the mixing characteristics of NCF was evaluated with the mixograph. Masas were subjectively evaluated for machinability properties. Masa with a low moisture level (51%) had reduced mobility and firmer texture, resulting in higher and wider mixograms. The mixograph was able to differentiate between the various stages of masa preparation. The first stage involves hydration of NCF particles, which causes the force to increase. Then masa develops cohesiveness and reaches maximum consistency. Finally, masa develops stickiness due to overmixing, which makes the curve narrower and lower. At a high moisture level (58%), masa is lubricated and plasticized and yields a softer texture with reduced mixing consistency, evident on the mixograph and in lower subjective hardness readings. Flours with higher water absorption capacities produced thick slurries with increased RVA viscosities and shorter consistometer travel distances. Short consistometer travel distances were significantly correlated to increased initial and maximum viscosities in the RVA. The mixograph, RVA, and consistometer methods can be used in NCF quality control programs.