Pulsed electric fields-assisted acetylation of starch

Abstract

In this chapter we mainly discuss the effects of pulsed electric fields (PEF) on acetylation of starch. The physicochemical properties and crystalline structure of PEF-assisted acetylated starch are summarized and analyzed by spectroscopic, microscopic, thermal, and physical techniques. The mechanism of PEF-assisted acetylation of starch has also been speculated. When handled with PEF treatment, electric potential difference is generated between the electrodes which can accelerate the mobility rate of reaction ions and change their moving directions (bipolar) resulting in more effective collision. In addition, effective channels induced by PEF treatment is proposed to introduce the targeted groups and water molecules into starch granules. Another significant reason for enhancing acetylation is due to the sufficient energy transferred to the reaction system. Meanwhile, deformation in particles and improvement in properties can be observed in starch granules treated by PEF with high intensity. Due to its prominent freeze-thaw stability of acetylated starch assisted by PEF treatment, the modified starch acetate exhibits its potential and superior application in frozen food products. Therefore, PEF-assisted acetylation of starch could be a valuable protocol as well as a time-saving, less reagent-consuming method for improving degree of substituent (DS), properties, and the structure of starch granules.