Heats of Dehydration of Starch Gels

Abstract Integral heats of dehydration have been measured by simultaneous differential thermal analysis (D.T.A.) and thermogravimetric analysis (T.G.A.) for gels of wheat starch. The results are interpreted on the basis that removal of water involves three structural changes: (a) Breakdown of starch‐water interaction (endothermic); (b) Breakdown of water‐water interaction (endothermic); (c) Increase in starch‐starch interaction (exothermic). On balance, the overall process is endothermic. It has also been shown qualitatively that the formation of gels from starch and water is an endothermic process. It is suggested that the energy required to disrupt the structure of the starch granules during gelation is greater than the energy released by increased starch hydration.