PHYSICAL AND CHEMICAL MODIFICATION OF THE STARCH. A REVIEW
Keywords:krakmolas, cheminis modifikavimas, fizikinis modifikavimas
The native starch an agricultural raw material used in many food and industrial products. It is present in granules that vary in shape of the form of amylose and amylopectin. Modification of starch is carried out to enhance the positive attributes and eliminate the shortcomings of the native starches. Modification of starch has numerous possibilities to generate novel starches which includes new functional and value added properties as a result of modification. This review summarizes well known and current methods that have been discovered in starch modification which includes two main areas that are chemical and physical modification. Oxidation, esterification, etherification, acid hydrolysis and cross-linking are some of the chemical modifications commonly employed to prepare starch derivatives. Physical modification is achieved through dextrinization, deep freezing, instantaneous controlled pressure drop process, mechanical activation with stirring ball mill, corona electrical discharges, thermally inhibited treatment and etc. Besides, chemical methods have been combined with physical modifications such as microwave, radiation and extrusion. Starch modification decreases retrogradation, gelling tendencies of pastes, gel syneresis and improves paste clarity and sheen, paste and gel texture, film formation and adhesion.