The Effect of Water and Fat Contents on the Enthalpy of Dissolution of Model Food Powders: A Thermodynamic Insight

Alejandro Marabi*, A. Raemy, A. Burbidge, Rony Wallach, I. Sam Saguy

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review


The dissolution process of food powders is a topic of vast practical and commercial importance. However, the physical and chemical processes involved are far from being fully understood. Calorimetric determination of dissolution enthalpies ( ä H diss ) of food powders enables the extent of solute - solvent interactions to be assessed in terms of thermodynamic parameters. In this context, this work studied the effect of water and fat content representing typical food powders on the enthalpy of dissolution measured by isothermal calorimetry. The model food powders were obtained by freeze - drying a mixture of skim - milk powder, maltodextrin, and variable amounts of butter fat. The moisture content (MC) was determined gravimetrically, and the enthalpy of dissolution was measured by isothermal calorimetry at 30 ° C. The powders were studied in the dry state and after equilibration at different water activity (a w ) values. Near - infrared spectroscopy and X - ray powder diffraction data indicated that the powders were in an amorphous state after freeze - drying. Crystallization of lactose was observed after exposure of the powders to the higher a w investigated. The enthalpy of dissolution decreased (less exothermic) with increasing fat content in the dry samples (MC = 1% dry basis [db]), ranging from 62 to 34 J/g for powders containing 0.7 and 45% fat (wet basis [wb]), respectively. The MC also had a signifi cant effect on the enthalpy of dissolution. The exothermic enthalpy decreased from 62 to 5 J/g for powders containing 0.7% fat (wb) in the dry state (MC = 1.7% db) and after equilibration at 0.54 a w (MC = 11.4% db), respectively. A similar trend was observed for all other samples, for which the exothermic ä H diss of the equilibrated samples decreased with an increase in the MC.

Original languageAmerican English
Title of host publicationWater Properties in Food, Health, Pharmaceutical and Biological Systems
Subtitle of host publicationISOPOW 10
Number of pages9
ISBN (Print)9780813812731
StatePublished - 14 May 2010


  • Determination of dissolution enthalpies - extent of solute-solvent interactions
  • Dissolution of model food powders - thermodynamic insight
  • Dissolution of powders - isothermal solution calorimetry
  • Exothermic response - dissolution of MD, SMP ingredients
  • Fat content of model powder - Mojonnier method
  • Recrystallization of lactose - contributing to endothermic response
  • X-ray powder diffraction (XRPD) - confirming samples in amorphous state


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