Preparation of Lauric Acid Modified High-Amylose Cornstarch by a Solvothermal Process and Its Pickering Emulsion

Based on the esterification of starch with fatty acids, high-amylose cornstarch (HACS) was modified with lauric acid (LA) by an ethanol solvothermal system. Using its relatively high temperature and a closed environment to improve the modification effect, the water contact angles of HACS increased from 44.5° of the original HACS to 79°, and the hydrophobicity of modified HACS (LA-HACS) was enhanced. Pickering emulsion was prepared by LA-HACS particle, corn oil, and water. Experimental results show that the oil fraction is 30% (v/v) and the addition of LA-HACS is greater than 40 mg/mL; a stable Pickering emulsion can be prepared. When the amount of LA-HACS is 55 mg/mL, the volume mean diameter (D43) of droplets reaches the minimum value of 8.68 μm at pH 9, and the absolute value of zeta-potential is 69.5 mV. Emulsion indices of the emulsion after 28 days was only 3.2% lower than that at 7 days, and there was no oil separation or demulsification. Therefore, the solvothermal system provides an effective and simple method to prepare starch particles for Pickering emulsion, having a practical potential in food products.