Commercial nixtamalized corn flours (CNCF) from three industrial plants in Mexico and traditional nixtamalized corn flour (TNCF) were used to study their particle size distribution (PSD), chemical analysis and dietary fiber analysis. The particle size of the flours were divided into five different fractions, 30, 40, 60, 80 and 100 US mesh, using a sieving machine. These were studied in relation to their peak viscosity and calcium content. The results indicated that the chemical analysis of CNCF and TNCF were found in equal amounts of protein, fat, ashes and moisture. However, the calcium content and total dietary fiber (TDF) is higher in the TNCF sample than in that of the CNCF sample. On the other hand, the PSD exhibited all unimodal distribution. The TNCF showed homogenous behavior in Calcium content and peak viscosity of the various sized fractions for different sleeping times (0, 1, 3 and 7 h). Nonetheless, the three CNCF were significantly different. It was concluded that the CNCF has approximately 1/3 more calcium content than that of TNCF. From a nutrimental point of view these results are very important especial in Mexico because nixtamalized products especially in tortillas is the main source of calcium for the general population. The foregoing results suggest that CNCF has to be fortified With Calcium and fiber after processing or the steeping times of the process must be incremented. (C) 2009 Elsevier Ltd. All rights reserved.