DSC studies of gamma irradiation effect on the amylose-lipid complex formed in wheat and potato starches

Influence of gamma irradiation (Co-60-rays) with doses in the range up to 30 kGy was studied on gelatinisation of wheat starch, wheat flour and potato starch. Differential scanning calorimetry was then applied at several heating and cooling cycles for studies of the effect of irradiation with a 30 kGy dose on interaction of wheat starch with their native lipids and potato starch with admixed 1-mono-lauroyl glycerol. Amylose-lipid complex transition occurs after irradiation at decreased temperature and is accompanied by decreased enthalpy in respect to that recorded in the case of non-irradiated wheat starch, wheat flour as well as potato starch and admixed lipid. Differences between the initial and irradiated starch were easier to detect on the foregoing heating or cooling cycles than during the preceding ones and after the gels' retrogradation. The complex was less influenced by the less advanced retrogradation taking place in the irradiated than in the non-irradiated wheat flour. Radiation-induced modification Of Structural properties of the complex results due to degradation of starch granules confirmed at present by essential reduction in pasting properties and by the increased amount of short molecular products leached during gelatinisation and their higher branching.