Comparative Study of the Performances of Octenyl Succinic Anhydride-Modified Agriophyllum squarrosum and Quinoa Starches to Stabilize Pickering Emulsions

Very small granule starch is a good source for effective Pickering emulsion stabilizers. In this study, native Agriophyllum squarrosum (A. squarrosum) starch (N-AS) and native quinoa starch (N-QS) are modified by octenyl succinic anhydride (OSA), and the physicochemical as well as the emulsifying characteristics of two modified starches are evaluated. Fourier transform infrared spectroscopy (FTIR) shows that the esterification reactions between OSA and the two starches are successful, and the substitution effect of OSA-modified A. squarrosum starch (OSA-AS) is better than that of OSA-modified quinoa starch (OSA-QS). X-ray diffraction (XRD) analysis shows that OSA modification does not alter the crystal type of the starch particles. OSA modification increases the particle size and hydrophobicity of both starches, and the particles of OSA-AS are smaller than that of OSA-QS, which corresponded to the fact that N-AS possesses a smaller particle size compared to native N-QS. OSA-modified starches are arranged at the interface of oil-water to stabilize the emulsion. The OSA-AS displays better performance of stabilizing emulsion than OSA-QS. The Pickering emulsions formed by all OSA-modified starch samples are mainly elastic gel-like emulsions. In summary, OSA-AS is more suitable for Pickering emulsion stabilizer than OSA-QS.