Cassava starch was extracted in different conditions with supercritical carbon dioxide. The morphological characteristics and the gelating properties of the treated starch

such as particle morphology

swelling degree

crystalline structure

viscosity

retrogradation and freeze-thaw stability

were evaluated and compared with native cassava starch by using scanning electron microscope

X-ray diffraction analyzer

Brabender visco-analyser or other methods. As a result

it showed that with the change of the pressure

temperature and time of the treatment

the morphology of the treated starch was not obviously changed

but the swelling degree decreased and the crystallinity increased. It also found that the anti-precipitability of the treated starch gel was strengthened and the freeze-thaw stability reduced. Meanwhile

Brabender viscosity analysis suggested that the gelation temperature of the treated starch could be slightly raised and the peak viscosity of the treated starch gel decreased

while the thermal stability little changed. All the results indicated that the cassava starch molecules could be partially degraded and the ratio of amylose to amylopectin would increase in the process of supercritical treatment

leading to the alteration of some microstructure characteristics and gelating properties of cassava starch.