Influence of hydrothermal processing on functional properties and grain morphology of finger millet

Finger millet was hydrothermally processed
followed by decortication. Changes in color, diameter, density,
sphericity, thermal and textural characteristics and also
some of the functional properties of the millet along with the
grain morphology of the kernels after hydrothermal processing
and decortication were studied. It was observed that, the
millet turned dark after hydrothermal processing and color
improved over native millet after decortication. A slight decrease
in grain diameter was observed but sphericity of the
grains increased on decortication. The soft and fragile endosperm
turned into a hard texture and grain hardness increased
by about 6 fold. Hydrothermal processing increased solubility
and swelling power of the millet at ambient temperature.
Pasting profile indicated that, peak viscosity decreased significantly
on hydrothermal processing and both hydrothermally
processed and decorticated millet exhibited zero breakdown
viscosity. Enthalpy was negative for hydrothermally
processed millet and positive for decorticated grains.
Microscopic studies revealed that the orderly structure of
endosperm changed to a coherent mass after hydrothermal
processing and the different layers of seed coat get fused with
the endosperm.