Crystallization kinetics of amorphous lactose as a function of moisture content using isothermal differential scanning calorimetry

Isothermal differential scanning calorimetry (DSC) was used to study the cr ystallization kinetics of amorphous lactose at 3 moisture contents. Each sa mple was heated to several temperatures between Tg and Tm, After subtractio n of an induction time, the Avrami equation was used to model the data and a Lauritzen-Hoffman like expression used to fit the crystallization rates b etween Tg and Tm. The highest Tm/Tg ratio and crystallization rate were obs erved for the sample containing the most moisture. Conversely the lowest Tm /Tg ratio and crystallization rate were observed for the sample containing the least moisture. Evidence for multiple transitions was seen. The Avrami equation may not be the best way to model such data.