Abstract
Heat treatments produce the ubiquitous endothermic transitions in the differential scanning calorimetry of biological substance-water systems. The transitions appear at the temperature ranges from 20 to 60°C depending on both of the temperature and the duration of the heat treatments. The transition enthalpies per gram of water in the sample lie between 2 to 20Jg-1 for the systems containing not so much water. These ubiquitous phenomena are explained as a memory effect of various kinds of weak hydrogen bonds formed in the biological substance-water system by the heat treatments.
