Effect of fat content on the dissolution enthalpy and kinetics of a model food powder

The enthalpy of dissolution of a model food powder containing increasing amount of fat was studied by means of isothermal solution calorimetry. The samples were characterized utilizing scanning electron microscopy (SEM), near infrared reflectance (NIR), and X-ray powder diffraction (XRPD). The water and fat content, specific surface area and density of the samples were also determined. Conductivity measurements were utilized to quantify the dissolution kinetics of the samples. All the samples showed an exothermic dissolution behavior, due to the amorphous state of their main components. The exothermic response decreased linearly as the fat content of the samples increased, possibly due to the reduced amount of amorphous material present in the samples. The dissolution rate was significantly affected by the amount of fat in the powder. The enthalpy of dissolution of a multi-component powder could be predicted from the additive enthalpy measured from its single components. The enthalpy of dissolution provides new and valuable information to better characterize the dissolution process of food powders.