Correlation of Thermal Conductivity of Instant Noodles with their Textural Property for Rehydration Study

A transient plane source method was introduced to an instant noodle system to characterize the rehydration property of noodles. The thermal conductivity of the white and whole wheat noodles was measured and correlated to their texture properties. The thermal conductivity of the noodles had a tendency to increase with increasing moisture content. Furthermore, a linear relationship (R2 > 0.95) was observed between the thermal conductivity of the noodles and their maximum extensional force depending on the moisture content. The thermal conductivity and maximum extensional force of noodles distinctly varied at the initial stage of cooking and then reached a plateau. However, their sensory firmness had a tendency to linearly decrease with cooking time. The change in the thermal conductivity of the noodles during cooking favorably correlated to the pattern of their maximum extensional force and rehydration rate. Practical Applications The improvement of rehydration rate of instant noodles has been a challenge faced by the food industry. However, the study on noodle rehydration is generally dependent on empirical and subjective measurements. In this study, a novel thermal technology based on the modified transient plane source method was utilized to characterize the rehydration property of instant noodles. One-dimensional upward heat flow was applied to measure the thermal conductivity of disc-shaped flat noodles. The thermal conductivity of the noodles was correlated with their instrumental and sensory texture properties depending on moisture content and cooking time. The method applied in this study can be utilized as a feasible tool to study the rehydration property of noodles during cooking by providing more scientific and fundamental thermal information.