Alternative methods to produce fresh corn masa and tortillas

摘要

Alternative laboratory methods to produce fresh corn masa and tortillas were evaluated. White corn (Asgrow 951) was abrasively decorticated to remove 5% of its initial corn weight. The decorticated corn was cracked, sieved and blended to produce decorticated corn pieces. Decorticated corn and pieces were cooked and held with limited water and 0.7% lime. Cooking was done at different times in a boiling water bath (heating method). Decorticated corn and pieces were held for different times and temperatures. Nixtamals were stone-ground into masas and selected masas were processed into tortillas. Masas and tortillas prepared by the traditional nixtamalization method were used as control. Masas were evaluated for moisture, pH, color and subjective machinability. Three treatments from preliminary experiments were selected to produce tortillas on a pilot plant: decorticated corn pieces cooked for 4 min and held 1 hr at 90°C; decorticated whole corn cooked for 8 min and held 1 hr at 90°C; decorticated whole corn cooked for 12 min and held 15 hr at 60°C. Masas produced using selected treatments (pilot plant scale) had very good machinability properties, compared to the control. Tortillas prepared using these treatments had acceptable texture (objective and subjective), flavor and aroma, compared to the control. Tortillas prepared by alternative methods were darker than the control, which might be due to the presence of corn pericarp which contains phenolic compounds that are very sensitive to pH and affect color, especially during alkaline processing. The color of the tortillas was still acceptable (personal evaluation).;Flavor and aroma of tortillas prepared by either alternative or traditional methods were similar, according to a trained sensory panel. The best treatment was the decorticated corn cooked for 8 min and held for 1 hr at 90°C. The use of these alternative methods can reduce dry matter losses, eliminate wastewater, reduce processing time and may reduce energy costs.;These experiments suggest that decortication of corn to partially remove the pericarp followed by cooking the decorticated corn in limited water containing 0.7% lime can be used to produce nixtamalized corn products similar to products from traditional nixtamalization process.