Preparation and Characterization of Starch Nanocrystals
Starch is a well-known and highly characterized biopolymer comprised of blocklets of semicrystalline segments. The crystalline segments of starch granules can be isolated by mild acid hydrolysis employing either hydrochloric or sulfuric acid. This results in the formation of starch nanocrystals, which have attracted growing attention in recent decades for their interesting and unique properties. This chapter critically reviews the recent advances in the preparation of starch nanocrystals and reports the critical steps needed to modify them chemically for new applications. Novel and improved techniques are outlined in order to optimize the preparation of starch nanocrystals from a wide range of starch sources. Advanced methods used to characterize starch nanocrystals and to understand their interactions with polymer matrices are also reported. In addition, the physicochemical properties, including mechanical, barrier, morphological, thermal, swelling and emulsification, are presented with potentially new insights into the development of starch nanocrystals for industrial applications.