Lectures L 9 . 1 The impact of molecular structure of starch on its applications

Starch is an important biopolymer, which is used in various branches of industry including food technology, mining, textile and paper industry. The divergence in applications causes the need of different technological parameters, such as granularity, solubility, viscosity, molecular weight. These features are controlled by molecular structure of starch, which is complex and covers all levels of organisation. According to botanical origin starch granules differ in shape, size and physico-chemical properties. The internal structure of granules includes semi-crystalline and amorphous regions, build up of branched and linear macromolecules. The degree of branching may vary depending on both botanical origin and activity of enzymes involved in biosynthesis of starch. This may be controlled by plant biotechnology and leads to the mutations with extremely high levels of branched or linear fractions. In order to improve starch properties, its molecular structure is o en modified by physical, chemical or enzymatical methods. Their applicability depends, however, on the internal features of starch, so it is very important to investigate native starch of various botanical origin. There is plenty of methods that may be used to elucidate starch structure: from different kinds of microscopy, through spectroscopy and light sca ering up to chromatographic methods. The knowledge of detailed starch structure could give preliminary information about technological value of starch, without the need to perform technological tests. Because starch is a very complex biosystem the growing popularity of application of starch at many fields follows with even more sophisticated research focusing on the relation beetwen structure and properties.