Understanding and Modifying Water Uptake of Seed Coats Through Characterizing the Glass Transition

The glass transition temperature (Tg) of seed coat was studied in relation to water uptake behavior. Tg values of seed coats were determined using differential scanning calorimetry (DSC) for selected pea and bean varieties. Rapidly hydrating samples showed a sharp Tg near ambient temperature with a range spanning 4–10°C. Samples that demonstrated a lag and consequently slow hydration exhibited a broad Tg above ambient temperature with a range spanning 22–33°C. Slow hydrating samples were processed via cyclic heating and cooling above and below Tg, resulting in elimination of the lag phase and markedly improved hydration rates. This research showed that Tg can be related to water uptake behavior and can be used as a parameter to determine processing conditions for improving water uptake in seeds.