Effects of maltose and fructose on the gelatinization and retrogradation of wheat starch

Abstract

This chapter explores the rheological and thermal properties of wheat starch to determine the effect of fructose and maltose on the gelatinization and retrogradation process. Wheat starch is used in paper making, foods, and confectionery. Freshly gelatinized oxidized wheat starch is used to stabilize milk products by increasing their consistency and viscosity.. Wheat starch granules are biconvex discs with a fairly regular circular outline. When starch granules are heated in excess water, a phase transition from order to disorder called gelatinization occurs. During gelatinization, several changes occur simultaneously, including uptake of heat by starch granules and loss of crystallinity as measured by X-ray diffraction. The thermal properties of wheat starch in aqueous solution are observed by differential scanning calorimetry (DSC) analysis. The effect of saccharides on the gelatinization and retrogradation process of wheat starch is investigated. The retrogradation ratio is determined from the values of the heating enthalpy and reheating enthalpy. The results show that adding maltose than fructose reduces retrogradation. The viscosity of wheat starch with or without fructose or maltose is observed as a function of shear rate and temperature using a cone and plate viscometer. The values of viscosity decrease with increasing shear rate and temperature.