The powder samples were tested in a TMA (Q800, TA Instruments, UK) using a cup and plunger test rig developed at CSIRO.
The compressionfixture for theTMAconsistsof anopenendedcup
made fromaluminiumandaplungermade frombrasswhichfitted
into the compression rig of the TMA instrument. The cup had an
internal diameter of 4.5mm and a height of 7.6mm. The plunger
had a diameter of 3.8mm and a length of 5.6mm.
Thecompressioncupwasfilledwith0.3±0.02gof samplepowder and a cap of silicone vacuum grease was applied to reduce
moisture loss. The plunger was broughtinto contact withthe sample. A constant force of 5N was applied to the powder while the
temperature was increased from −50◦
C to 300◦
C at 3
◦
C/min. The
position of the plunger was monitored throughout the temperature sweep while the sample was under a constant compression
load. Collection and analysis of the data was done through the
Universal Analysis 2000, version 4.2E software. The temperature
lag ofthe sample holder was determined using the melting points
of acetonitrile, water and benzoic acid giving an average result of
14.5±2.1◦
C. The raw data for the starch and starch/gluten blend
were adjustedtocompensate for the temperature lag.Eachsample
was runatleasttwice. The onset,midpoint andendpointtemperaturesoftheT
g transitionswerecalculatedusingthetangentsdrawn
on the displacement curve. Mean and average deviation from the
mean was calculated for each value.