Effect of octenyl succinic anhydride starch ester by semi-dry method with vacuum-microwave assistant

Corn starch was esterified with octenyl succinic anhydride (OSA), in which semidry method assisted with vacuum-microwave treatment was used under the alkalescent condition. The effect of vacuum treatment on esterification was studied. The products were characterized by Fourier transform infrared (FT-IR) spectroscopy, ¹H nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) and X-ray diffraction. And the emulsifying properties were investigated with the emulsifying capacity (EC), emulsion droplet size and confocal laser scanning microscopy (CLSM). The degree of substitution (DS) of OSA starch increased significantly (ρ < 0.05) assisted by the vacuum-microwave treatment with the same dosage of reactant compared with the microwave only. The results confirmed the formation of OSA starch prepared by the method, all reactions occurred mainly on the surface of granules, and had no significant effect on the starch crystallinity. The OSA starch was a good polymeric surfactant with good abilities both in hydrophilic and lipophilic. The emulsifying capacity, degree of substitution of the OSA starch prepared by the method attractively showed vast potential for scale production.