Changes in some physico-chemical properties of starch granules induced by heating and microwave radiation

Corn and potato starches were physically modified by heating at 130 and 200°C or microwaving. On a basis of the results obtained it was found that upon heating or microwaving the content of amylose decreased and the reduction capacity increased for most of the modified starch preparations and all the preparations had an increased swelling capacity and water solubility. The greatest changes were observed for the preparations heated at 200°C, irrespective of starch. Microwave radiation caused slighlty smaller changes in the properties of starches. In the case of the preparations from potato starch it was observed a considerable increase in specific surface area of granules, an increase in volume of mesopores, and a decrease in their average diameter. The changes in these values were small in the preparations from corn starch.