Instrumental methods for the evaluation of corn tortilla texture

Objective techniques (rollability, bending, tensile, puncture, and stress relaxation) that evaluate control tortillas and tortillas containing 0.75% CMC and 0.005% barley malt were developed and evaluated. The abilities of the objective techniques to detect texture differences in corn tortillas containing different additives were evaluated. The potential of using the objective technique to monitor tortilla texture in industrial settings was also evaluated.Objective rollability, bending and tensile techniques were more highly correlated to subjective rollability and flexibility than the puncture and stress relaxation test. Puncture technique measured the ability of tortillas to resist puncture, while stress relaxation measured the viscoelastic properties.The variability of the objective techniques was significantly affected by the uniformity of the sample (thickness, moisture content, and the extent of puffing), however, among homogeneous samples, the variabilities were low.The bending technique produced low variability data on the commercial tortillas sampled on site or from selected Texas markets. It detected textural differences between table tortillas produced on different work shifts and between tortillas prepared for table consumption or chip use. The bending technique data on the commercial tortillas supported and were in accordance with the data collected on the laboratory tortillas.The variability in texture values of corn tortillas available on the market was detectable using both objective and subjective techniques. The objective techniques supplemented the data obtained in the subjective rollability tests and provided adequate information to help explain the changes in textural properties during storage or those caused by additives.The choice of the objective technique used depends on the application needed. For research and quality control in industrial settings, the bending and tensile techniques are recommended. They are fast, simple, perform as well in a laboratory facility as in an industrial production facility, and have potential to become a significant tool in monitoring texture in industrial settings. The stress relaxation technique is recommended for fundamental research in an academic setting. The technique provides information about viscosity and elasticity of corn tortillas that were not provided by the other techniques.