Cryogenic scanning electron microscopy (Cryo-SEM; Philips
XL30 FEG ESSEM) was used to visualise the microstructure of untreated
and heat-treated rice starch in water. One drop of starch
dispersion was frozen to approximately 180 C in liquid nitrogen
slush. Samples were then fractured and etched for 3 min at a
temperature of 90 C inside a preparation chamber. Afterwards,
samples were sputter coated with gold and scanned, during which
the temperature was kept below 160 C by addition of liquid nitrogen
to the system.