The extent of corn tortilla staling was quantified in terms of degree of amylopectin crystallization using data from stress relaxation and polymer crystallization theory. The staling process in corn tortillas was studied as a function of time (fresh up to 10 days) and storage temperature (6-35degreesC). Fresh corn tortilla has a lower value of stiffness than stale tortilla thus indicating how tortilla becomes firmer with time. The stiffness of tortilla decreases with increasing temperature. The Avrami-nucleation model was applied to the kinetic data. This model was selected to describe the extent of crystallization of amylopectin in corn tortilla using stress relaxation techniques in the temperature range of 6-30degreesC with the maximum nucleation rate at temperature of 12.3degreesC. Results correlated well with subjective measurements of tortilla rollability. (C) 2002 Elsevier Science Ltd. All rights reserved.