The influence of oxidation, extrusion and oxidation/extrusion on physico-chemical properties of potato starch.

The aim of the research was to compare several physico-chemical parameters of potato starch modified using oxidation, extrusion, and combination of both, including content of amylose and non-polysaccharide components, amount of carboxyl groups, molecular mass distribution of polymers, pasting ability, and rheological properties. It was observed that oxidation, extrusion, and combined oxidation/extrusion of starch resulted in an increase of ash in potato starch, and the oxidized starch contained the lowest amount of non-carbohydrate compounds. Oxidation resulted in a decrease of phosphorus, while its content after extrusion increased. It was found that the level of apparent amylose dropped after all applied types of modification. Water binding capacity and solubility of oxidized starch differed slightly from the values measured for native starch, while a huge change in these characteristics was caused by extrusion. The highest change of molecular mass was observed after combined modification and the lowest in case of extruded starch. Modification of starch affected its rheological properties, which exhibited low viscosity and was more susceptible to shearing forces. [ABSTRACT FROM AUTHOR]