Recent Advances in the Preparation and Characterization of Intermediately to Highly Esterified and Etherified Starches: A Review

Abstract Starch can be derivatized with various functional groups to achieve different physicochemical properties. For decades, researchers have focused on lightly substituted starches since these starches can be prepared economically in aqueous slurries. In contrast, modified starches having high or intermediate degree of substitution have not been thoroughly investigated or extensively used, mainly because their conventional preparation involves harmful solvents that renders their purification uneconomical. Aiming to explore possible industrially feasible routes for producing medium and highly substituted starch derivatives, this review summarizes developments in synthetic methods, especially the influence of synthesis media and reaction conditions. In addition, crucial physicochemical properties of those highly substituted starches are discussed.