Modification of potato starch
Application of native starch in food production is highly limited due to retrogradation, instability in acid conditions and at high temperatures etc. To overcome these problems and extend starch application, native starch is modified by chemical, physical and enzymatic procedures. The aim of this research was to prepare different modified starches from commercial native potato starch by acetylating (with acetanhydride), cross-linking (with sodium tripolyphosphate, STPP) and combination of these procedures, and to determine their rheological and thermophysical properties. The results showed that all modified starches had lower gelatinisation temperatures and lower gelatinisation and retrogradation enthalpy than native starch. Dual modification with higher proportion of cross-linking reagent resulted in 50%-decrease of gelatinisation enthalpy compared to native starch. Acetylated and acetylated cross-linked starch had lower peak viscosity, whereas cross-linked starch had higher peak viscosity than native counterpart. While acetylating resulted in increase of % breakdown, other applied modifications resulted in its decrease. Swelling power and solubility increased by acetylating and decreased proportionally to increase of cross-linking reagent both by cross-linking and dual modification.