Enthalpy-entropy compensation in sorption phenomena of starch materials

The enthalpy-entropy compensation theory was applied to the experimental moisture adsorption and desorption isotherm data (water activity (aw) range 0.006-0.982) of raw potato, potato starch gel, potato starch powder, highly amylopectin corn starch powder and highly amylose corn starch powder in the temperature range 30-60 °C. A linear relation existed between differential enthalpy (ΔH) and differential entropy (ΔS) for all the experimental data considered, thus satisfying the enthalpy-entropy compensation theory. Further analysis of the data indicated an enthalpy-controlled (isokinetic temperature (Tβ) > harmonic mean temperature (Thm)) and spontaneous (−ΔG) sorption process.