Structure and selected functional properties of gamma-irradiated potato starch

摘要

Potato starch was modified with gamma-rays applying doses of 5, 10, 20 and 30 kGy. The effect of irradiation on starch structure was assessed on the basis of blue value (BV), A(680)/A(545) ratio, apparent amylose content and lambda(max). The results showed that modification of starch led to the reduction of all parameters connected with the starch-iodine complex. The main effects of gamma-irradiation on starch granules revealed by scanning and transmission electron microscopies were cracks on the surface. Low-temperature nitrogen adsorption data showed that modification with gamma-rays increased specific surface area and volume of mesopores and decreased their average diameter. DSC data indicated decreased crystallinity of starch and facilitated retrogradation taking place after irradiation in the 20% starch gels. Treatment with gamma-rays influenced also functional properties of potato starch increasing water absorption, least gelling concentration, solubility, paste clarity and susceptibility to alpha-amylolysis, and decreasing fat absorption and viscosity.