Relating mechanical changes at the glass transition with water absorption behavior of dry legume seeds

This work provides a novel view of explaining water uptake behavior commonly observed in legume seeds. A model proposed by Peleg to describe the mechanical changes in biomaterials transitioning from a glassy state to a rubbery state was used to describe water uptake by legume seeds exhibiting a lag during imbibition and to characterize the mechanical changes of the seed coat as affected by soaking time. The seeds characterized by Peleg's model possessed seed coats with a glass transition temperature higher than ambient soaking conditions. Alternatively, the water uptake behavior of legume seeds that did not exhibit a lag phase was characterized by an exponential equation used in polymer science to model solvent sorption by materials above their glass transition. A modified exponential equation was developed to model the mechanical behavior of these seed coats as affected by soaking time. Seeds characterized by the exponential equation possessed seed coats with a glass transition temperature near ambient soaking conditions. This work demonstrates, through the use of two separate models, water uptake behavior of legume seeds can be explained by the glass transition temperature of the seed coat. Copyright © 2010 The Berkeley Electronic Press. All rights reserved.