Interpretation of the force-deformation curves of cooked red lentils (lens culinaris)

The effect of cooking time on the textural properties of red lentils was determined using an Instron universal testing machine equipped with an Ottawa texture cell. A sigmoid-shaped force-deformation curve was observed for all samples. As cooking time increased, texture changes, in terms of undercooked and optimally cooked, were identified by changes in slope and plateau force values of the force-deformation curves. At short cooking times, the samples were undercooked, and slope and plateau force values were high. At prolonged cooking times, slope and plateau force values decreased to a certain point and became independent of cooking time as values leveled off. However, significant textural changes as determined with sensory methods continued. Cooking time affected the location of the inflection point on the force-deformation curve. Deformation at inflection was a parameter that successfully determined textural differences between cooked samples and overcooked samples. Force-deformation curves can describe cooking quality of red lentils. © 2009, Wiley Periodicals, Inc.