Starch is one of the major polysaccharides used by plants for energy storage. It is widespread in seeds, roots and tubers as well as in stems, leaves, fruits and pollen. It consists of amylose and amylopectin in different ratios, which depends on the botanical origin of starch. Starch forms with triiodide a complex of violet-blue colouration, a starch-triiodide complex [1] (the colour depends on the starch nature). These reactions have been studied extensively by many investigators and are used widely for determining the amylose content of starches by both potentiometric and spectrophotometric methods. The subject has been reviewed by Banks and Greenwood [2] and given additional study by numerous workers. Our approach is based on the redox potential and absorption change. At different starch concentrations, the change of triodide ion concentration (which exists only in excess of iodide ion) causes the change of the triiodide/iodide redox couple ratio, which results with the changes the electrode potential of a redox sensor according to the Nernst equation. The composition and stability of potassium triiodide (KI3) solution have been optimised and mathematical model for starch-triiodide complex stoichiometry has been proposed. The electrode potential changes were used for the development of a new potentiometric starch sensor. The aim of these investigations was the development of a new fast and reliable sensing methodology for starch quantification using potentiometric and optical sensing principles.

Chemistry