Native starches have limitations such as low tolerance to processing conditions, excess viscosity, and pH sensitivity. Modifying starches through physical, chemical, and enzymatic processes can overcome these limitations.
Thermoplastic starch has poor water resistance, which limits its applications. Chemical modifications, such as esterification, etherization, and oxidation, can effectively overcome this drawback.
Starches can be modified by introducing functional groups through chemical methods, such as oxidation and esterification, to improve their applicability in various industries. Starches can also be physically modified through moist heat treatment and annealing.
Cross-linking changes both the physical properties and thermal characteristics of starch. The effect varies based on the type of starch and cross-linking agent used. Cross-linked starch can slow retrogradation and raise the gelatinization temperature due to the formation of intermolecular bridges that restrict the movement of amorphous chains within the starch granule.