The instrument was calibrated with indium metal as a standard,
and all the measurements were performed under a nitrogen
flow (20 mL/min). Flour (10 mg, db) and distilled water (20 μL) were
placed in a stainless steel sample pan, hermetically sealed, and then
equilibrated for at least 30 min at room temperature. Each sample was
heated from 20 °C to 180 °C at a heating rate of 10 °C/min, then immediately
cooled to 20 °C (cooling rate: 40 °C/min), held at this temperature
for 1 min, and finally reheated to 180 °C at a heating rate of
10 °C/min. A capsulewith aluminumoxide andwaterwas used as reference.
For each endothermic peak, the onset temperature, offset temperature
and peak temperaturewere determined using PyrisManager data
processing software (Perkin Elmer). The transition enthalpy (J/g, db)
was calculated from the peak area. Results are the average of at least
two measurements.