EFFECT OF MICROWAVE IRRADIATION ON SELECTED PHYSICAL AND CHEMICAL PROPERTIES OF CORN STARCH AND CORN MALTODEXTRINS SHOWING DIFFERENT DEXTROSE EQUIVALENTS

The objective of the study was to assess the impact of microwave irradiation on the selected physical and chemical properties of corn starch gels and hydrolysates produced from corn starch. The research material constituted a corn starch and corn maltodextrines showing a medium and high degree of saccharification. All samples of the initial material were heated in a 400 W or 800 W microwave oven. Next, the contents of protein and fat were determined in the samples, as were the colour parameters; the sensitivity of starch and its hydrolysates to retrogradation was analyzed; the flow curves were drawn of 2 % starch paste and of 40% solutions of maltodextrins, at a temperature of 50 degrees C. It was proved that the physical modification of both the corn starch and its hydrolisates contributed to the change in the fat content and in the values of colour parameters of the samples analyzed; however, it did not impacted any change in the content of proteins. The heating of the starch and maltodextrins in a microwave field caused the turbidance value to decrease over the entire period of analyses. In contrast, when rheological determinations were performed, it was found that the physical modification impacted the value of shear stresses during the analyses of maltodextrin solutions. However, no effect was found of the microwave irradiation of the corn starch and maltodextrins studied on the change in the rheological parameters of the samples prepared from the initial material studied.