Abstract: The aim of this study was to determine the differences in the physicochemical properties of starch granules extracted from native and microwave precooked white sorghum by scanning electron microscopy, polarizing microscopy, differential scanning calorimetry, X-ray diffraction and Fourier transform infrared spectroscopy. It was found that the polarized crosses of the microwave-treated starch became more blurred, with nearly half disappearing. In addition, the starch granules became swelled, along with a reduction in resistant starch, relative crystallinity, phase transition temperature range and endothermic enthalpy. But both starches had the same structural characteristics as demonstrated by the infrared spectra of the samples. The results showed that microwave treatment was helpful for starch gelatinization while not changing the chemical composition of white sorghum starch.

Key words: microwave treatment, white sorghum, starch, physicochemical properties