EPR study of the influence of high hydrostatic pressure on the formation of radicals in phosphorylated potato starch

Phosphorylated potato starch reveals smaller values of the melting enthalpy and lower crystallinity than the native one, indicating weakening of the structure upon incorporation of phosphorus. Nevertheless, changes in transition temperatures To and Tp suggest that certain cross-linking reactions occur in the case of distarch phosphates. Heating at 210–230 °C causes easier generation of radicals in phosphorylated than in the native starch. Pretreatment of the phosphorylated starch with high hydrostatic pressure somewhat diminishes the number of thermally generated radicals. Both effects, increase in the number of radicals upon phosphorylation and its decrease upon pretreatment of the starch with pressure, are more pronounced for monostarch than for distarch phosphates, most probably due to the cross-linking reactions occurring in the distarch phosphate samples.