Preparation of W/O Emulsions. Water-in-oil emulsions were prepared by homogenizing 20 wt % aqueous phase with 80 wt % oil phase. The emulsions were prepared at 40-50 °C (rather than at room temperature) because we found that the oil phase was less viscous, and the emulsions produced by homogenization had smaller droplet sizes (see later). The aqueous phase with or without 15 wt % WPI was dispersed gradually into the oil phase under agitation with a magnetic stirrer and then blended together using a high-speed blender (M133/ 1281-0, Biospec Products, Inc., ESGC, Switzerland) at 50 °C for 2 min. The coarse emulsions were then passed through a two-stage highpressure valve homogenizer (LAB 1000, APV-Gaulin, Wilmington, MA) three times: 19 MPa (2700 psi) for the first stage and 2.1 MPa (300 psi) for the second stage. Temperatures of the emulsions were 45 ( 1 and 44 ( 1 °C when they were fed into and came out of the homogenizer, respectively. After homogenization, the emulsions were cooled to room temperature (∼23 °C). Then, the emulsion containing water droplets with WPI inside was separated into two portions: (i) one portion was maintained at ambient temperature; (ii) the other portion was heat-treated at 80 °C for 20 min. All emulsions were then stored at ambient temperature for 24 h before being analyzed.