The study on indirect determination of damaged starch in wheat flour

Abstract

Damaged starch content in wheat flour significantly influence the technological quality and utilization of flour as well as the quality of the final products. The level of mechanically damaged starch depends on wheat variety, wheat hardness, milling conditions and wheat preparation prior to milling. A number of methods have been developed to measure the content of damaged starch such as microscopic, polarimetric, spectrometric, enzymatic and/or amperometric methods. This study is based on the idea that the level of the damaged starch also influences the rheological properties (e.g. viscosity) of wheat flour suspension. Since the damaged starch granules are easily susceptible to the α-amylase digestion, in order to study the viscosity of wheat flour suspension, the inactivation of α-amylase with silver nitrate was performed. The rheological properties of wheat flour suspension were performed by rotational rheometers before and after α-amylase inactivation. Simultaneously, the level of damaged starch was determined by amperometric method. The relationship between the differences in rheological properties of wheat flour suspension before and after inactivation of α-amylase and damaged starch content indicates the possibility to indirectly determine the damaged starch content by application of rheological method.