The Polymeric Carbohydrate: Starch – Extraction and Modifications

This chapter is divided into four sections: (i) a brief overview, (ii) extraction processes, (iii) modification processes of starch, and (iv) final considerations. These sections provide valuable insights into the starch structure, starting with its fundamental formation involving D-glucose molecules, followed by the conformations of its polymer chains, namely amylose and amylopectin. Furthermore, detailed information about the complex hierarchical levels proposed for starch structure is presented, aiming to assist in understanding the relationships between its structure and properties: starch’s molecular architecture, supramolecular structure, and granular structure. Extraction processes are described and categorized based on the commonly used sources, including cereals, roots, and tubers. Lastly, various modification processes applied to starch native or after the extraction process are presented, along with the significant physicochemical and functional properties affected by each specific modification. The processes of starch modification are generally guided by demands related to functional properties. Structural modifications can be obtained by substituting hydroxyl groups with functional chemical groups, such as carbonyls or electronically charged groups, resulting in cationic and anionic starches. Additionally, it is possible to obtain starch nanostructures, produce porous starches, promote changes in the amylose:amylopectin ratio, and reduce polymeric chains, among other modifications.