Effect of microwave radiation on physico-chemical properties and structureof cereal starches

Wheat, corn and waxy corn starches of intermediate moisture content (30%) w ere subjected to microwave processing and the effect of microwave radiation on physico-chemical properties and structure of cereal starches was studie d. The experimental starches were examined by the Brabender rheological met hod, light microscopy, X-ray diffractometry and differential scanning calor imetry. Microwave radiation was evidenced to cause a shift in the gelatinis ation range to higher temperatures, and a drop in solubility and crystallin ity. The extent and type of these changes depended on the variety of starch . Normal corn and wheat starches underwent pronounced changes, whereas unde r the same conditions waxy corn starch was almost unchanged. It was conclud ed that susceptibility of different starches to changes due to microwave ir radiation depended not only on their crystal structure, but also on their a mylose content. (C) 2000 Elsevier Science Ltd. All rights reserved.