The glass-transition temperature (Tg) of films and the degree of
denaturation of protein products were determined by differential
scanning calorimetry, with a DSC TA 2010 calorimeter Model Q100
V9.8 Build 296 (TA Instrument, New Castle, DE, USA) controlled/
regulated by a TA 5000 module with a quench-cooling accessory.
The temperature and heat-flow calibration of the equipment were
carried out according to ASTM indications, with lauric and stearic
acids plus indium as standards. Hermetically sealed aluminum
pans containing 10–15 mg of film were prepared and scanned at
10 1C/min over the range 100 to 220 1C in order to determine
the value of Tg. This parameter is defined as the inflexion point
of the base line, caused by the discontinuity of the specific heat of
the sample and in these experiments was calculated by means of
the Universal Analysis V4.2E software (TA Instruments, New