Calorimetry and Thermogravimetry of Bound Water in Dried Milk and Whey Powders

Open Access
Publisher Website
Google Scholar
Abstract
Hermal data show that water is sorbed by milk and whey powders through pri- marily weak binding forces at low to intermediate relative humidities. Heat re- quired to release and vaporize such bound water, as determined by differential scan- ning calorimetry is 10.1 +-- 0.4 kcal per mole of water desorbed from whole or skimmilk powders. When milk or whey powders sorb sufficient water, at ~-~ 50% relative humidity, to induce lactose crystal- lization or changes in protein conformation, the differential scanning calorimetry pat- tern becomes more complex, desorption is completed at a higher temperature and the enthalpy of desorption increases by 1.44 to 2.44 kcal per mole.