was used as a reference in each test and nitrogen was used as the
carrier gas (300 mL/min).
2.2.1. Glass transition of samples containing unfreezable water
Samples (containing unfreezable water) placed in sealed aluminum
pans were cooled from ambient temperature to 90 C at
5 C/min, held for 10 min and heated at 5 C/min to 60 C. They
were then scanned from 60 to 90 C at 5 C/min and reheated
at 5 C/min up to 60 C. A double scanning program of the samples
was used in this method to reduce the enthalpy relaxation of the
amorphous samples, which appears in the first scan. In addition,
through the second scanning, a clear baseline shift of the glass
transition could be observed (Telis and Sobral, 2001; Shi et al.,
2012). The experiments were performed in triplicate to determine
the glass transition temperature at each water content