Physicochemical properties of potato starch illuminated with visible polarised light

Suspensions (30%, w/w) of potato starch in pure water were illuminated for 5–50 h by linearly polarised visible light (λ>500 nm) under stream of nitrogen. Effects of the illumination on the transition enthalpy, melting temperature, the pasting viscosity profiles, and iodine binding capacity of illuminated starch were examined. Starch illuminated in water for 50 h showed lower melting temperature Tp (60.57 °C) and transition enthalpy ΔH (10.01 J/g) than original potato starch soaked in water for the same period. After 25 h illumination in water the peak paste viscosity, Pv, of starch decreased in order to raise after 50 h illumination. Illumination in water initially degraded starch but prolonged illumination resulted in crosslinking into material of higher molecular weight.