High-speed shear effect on properties and octenylsuccinic anhydride modification of corn starch

The reaction between starch granules and octenylsuccinic anhydride (OSA) is normally retarded due to poor penetration of big oily OSA droplets into starch granules in an aqueous reaction system. High-speed shear was used to improve the degree of substitution (DS) and reaction efficiency (RE) of octenylsuccinate (OS) starch. Effects of high-speed shear on the physicochemical properties of corn starch and OS-starch synthesis were investigated. Results showed that no significant difference was observed in melting temperature and crystalline structure of treated starch when shear rate was less than 1.5 × 104 rpm. Treatment could degrade the starch molecule and release soluble saccharides. High-speed shear treated starch (H-starch) exhibited lower enthalpy change, and higher stability of hot and cold paste. OS-starch prepared using high-speed shear (H-OS-starch) showed more homogenous substitute group distribution in starch granule than that of control, as shown by confocal laser scanning microscopy. H-OS-starch also showed higher DS and RE, slightly lower pasting temperature, higher stability of hot and cold paste, and higher clarity and freeze-thaw stability, compared with the control.