Relationship Between Objective and Subjective Wheat Flour Tortilla Quality Evaluation Methods

Accurate determination of tortilla quality is imperative because of the growing market. This calls for quality tests that are replicable. However, current tortilla quality testing relies heavily on subjective tests with unknown reliability. This study aimed to determine the relationship between subjective tortilla quality testing and available objective methods, and assess whether the latter can potentially replace the former. Correlation and regression analyses were done using data on subjective opacity and rollability, and objective L* value and texture parameters based on 114 wheat samples. Opacity scores and L* values were significantly correlated, but this relationship was affected by evaluator experience; in a controlled setting, experienced evaluators scores were more reliable (SEM = +/- 0.25 - 3.8, r = 0.96) than less experienced evaluators (SEM = +/- 0.25 - 7.3, r = 0.92). Tortilla rollability, which approximates shelf stability, correlated most strongly with the rupture distance from two-dimensional extensibility test (r = 0.77). Subjective rollability at day 16 of storage was predicted by rupture distance (day 0) and work (day 4) (R-2 = 0.69). Adding rupture force to the model slightly improves the R-2 to 0.72. Objective color and texture parameter measurements have a potential to replace the subjective tests as primary methods for tortilla quality.