A cost-effective, faster and efficient way of screening wheat samples suitable for tortilla production is needed. Hence, we developed prediction models for tortilla quality (diameter, specific volume, color and texture parameters) using grain, flour and dough properties of 16 wheat flours. The prediction models were developed using stepwise multiple regression. Dough rheological tests had higher correlations with tortilla quality than grain and flour chemical tests. Dough resistance to extension was correlated best with tortilla quality, particularly tortilla diameter (r= -0.87, P<0.01). Gluten index was significantly correlated with tortilla diameter (r = -0.67, P less than 0.01) and specific volume (r = -0.73, P less than 0.01). Tortilla diameter was the parameter best predicted. An r2 of 0.87 was obtained when mix-time and dough resistance to extension were entered into the model. This model was validated using another sample set, and an r^2 of 0.91 was obtained. Refined and whole wheat flours, dough and tortillas were compared using five wheat samples. Refined flour doughs were more extensible and softer than whole wheat flour doughs. Whole wheat flour tortillas were larger, thinner and less opaque than refined flour tortillas. Refined wheat flour had much smaller particle size and less fiber than whole wheat flour. These are the major factors that contributed to the observed differences. In general, refined wheat tortillas were more shelf-stable than whole wheat tortillas. However, whole wheat tortillas from strong flours had excellent shelf-stability which must be considered when whole wheat tortillas are processed. . Different objective rheological techniques were used to characterize the texture of refined and whole flour tortillas during storage. Differences in texture between 0, 1 and 4 day-old tortillas were detected by rupture distance from one and two-dimension extensibility techniques. In general, the deformation modulus was not a good parameter to differentiate tortilla texture at the beginning of storage. It detected textural changes of 8 and 14 day-old tortillas. The subjective rollability method detected textural changes after 4 days storage.

The effects of different types and amounts of sodium bicarbonate (NBC) were evaluated during the processing of flour tortillas. Fat encapsulated NBC, BS199, BS195, BS193, BS180, BS184, HM50 and HM70, and different particle-sized, non-encapsulated NBC, grade 1, grade 2, grade 3 and Tortilla Blend TM, were tested at different levels and combinations. Longer shelf stable tortillas with lower opacity were obtained when the level of NBC decreased. Tortillas with higher opacity, diameter and volume were obtained using the correct types of NBC. Increased tortilla opacity, thickness and shelf stability were obtained using 3 g encapsulated NBC/kg compared to non-encapsulated NBC. Encapsulation of NBC enables a temperature-triggered leavening reaction during baking of tortillas. Combinations of different levels and ratios of fast- and slow-release NBC did not yield significant improvements in tortilla properties. Tetrasodium pyrophosphate (TSPP, 0.15%) was added to modify protein functionality in tortilla dough containing less NBC. Tortillas with improved opacity, thickness and shelf stability resulted using TSPP with 3 g Grade 1 NBC/kg but similar improvements were not seen with encapsulated NBC. The effects of TSPP with low levels of NBC and slow reacting leavening acids were tested. Slight improvements in opacity were observed with sodium aluminum phosphate (SALP) compared to sodium aluminum sulfate (SAS) using encapsulated and non-encapsulated NBC. Tortillas produced with these formulations have longer shelf stabilities with similar properties. This benefits the consumers. The manufacturing costs for ingredients are 1.2% less using 0.15% TSPP with 3 g non-encapsulated NBC/kg flour. The manufacturer gains not only by the reduced cost of ingredients but also by the increased ease of attaining target diameter of tortillas. This could also be accomplished by using less dough to form the tortilla.