  Inulins are nano-meter size semi-crystalline particles, composed of
oligomeric fructose units. It has been subjected to fine micro-structural
analysis under temperature variations using mainly positron annihilation
spectroscopy. The results show a non-monotonous temperature sensitive behaviour
of the positron parameters, with considerable variation of its free volume
size. The ortho-positronium pick-off component shows a major thermotropic
transition at ~320K and a structure loss due to glass transition. Differential
scanning calorimetry confirms the onset of the major molecular transition
around the same temperature with an enthalpy change of {\Delta}H ~379J /gm and
thermo-gravimetric analysis shows mass loss in the said transition. Keywords:
Inulin, fructose units, positron annihilation spectroscopy, microstructure,
free volume analysis. thermotropic transition, thermal analysis.
