*4.1.4 Emulsification*

Plant protein exhibit emulsifying properties. This relates to their ability to stabilize oil in water and water in oil emulsions thereby reducing interfacial tension and phase separation [15, 52, 53]. Thus they play a role as emulsifiers due to hydrophobic and hydrophilic balance at the interface of oil and water. Proteins align at interface so that the hydrophobic part face the oil phase, while its hydrophilic part face the water phase. Emulsification properties can be measured using methods such as turbidimetric method and droplet size measurement. The former comprise emulsifying activity index (EAI) and emulsifying stability index (ESI). Emulsification properties of legume protein affected by pH, temperature, protein concentration, and ionic environment [46]. Bean and pea protein isolates were reported in a study to have similar emulsifying capacity of about 27%, but emulsion stability was higher for pea protein isolate [54]. A study reported emulsifying activity index and emulsifying capacity index of protein isolates from 7 cultivars of pea to be 31.09–39.05 m2 /g and 10.97–11.26 min, respectively [49]. Pea and soybean protein products are one of the most characterized and used in food applications.
