Abstract
The effect of pericarp and nixtamalized corn bran (NCB) level on corn tortilla attributes was evaluated. The effect of varying pH (4, 9 and 11) on fresh and dry mesa flour (pH 5, 7 and 10) tortillas was also evaluated. Nixtamal was washed at three different levels to obtain tortillas containing about 0, 50 and 100% pericarp. Fumaric acid and lime solutions were used to produce acidic and alkaline tortillas respectively. Tortilla texture was evaluated at 0, 1 and 7 days of storage objectively using a texture analyzer and subjectively using a solvability test. As pericarp content and pH increased tortillas were softer, more flexible and extensible with a darker yellow color. Acidic tortillas were harder with a white color. Pericarp improved texture of tortillas during storage. Commercial corn bran was alkaline treated to obtain NCB with functionality similar to nixtamalized corn pericarp. Dry masa flour (DMF) (1 kg) was mixed with 0, 50 and 100 g dry basis of NCB and processed into tortillas. Tortillas containing NCB had a pH of 9, were more flexible and rollable than control tortillas. Alkaline pH tortillas puffed during baking; these tortillas were yellow with a soft, moist texture. Tortillas containing nixtamalized rice and wheat brans were soft and flexible. A sensory panel found that tortillas containing nixtamalized cereal brans had a strong alkaline flavor and aroma and a blistered surface, with a soft, moist texture. NCB tortillas had the highest overall acceptability scores. Pericarp from nixtamal and alkaline pH slowed the staling mechanisms of tortillas. Nixtamalized commercial brans significantly improved the texture of corn tortillas during storage and enhanced the color, flavor and aroma of DMF tortillas. Nixtamalized cereal brans can be used as an effective additive to extend shelf stability of tortillas and enhance the flavor of DMF products. Tortillas containing NCB could be used in products such as wraps and fried tacos where the bright color and stronger flavor could be an advantage.
Guajardo Flores, Sara (1998). Functionality of alkaline cooked corn bran on tortilla texture. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1998 -THESIS -G83.