Abstract: EC (Emulsifying Capacity ) is one of the most important functionalities of soybean protein isolates It’s very necessary to establish a scientific and practicable method to determine it. According to the physico-chemical properties of soybean protein EC (Definition 3) was defined and the influential factors were systematically studied.The experimental results showed that there were some factors including emulsifying method sample’s concentration different oils temperature and NaCI content having effects on EC to certain degree. Under defined emulsifying condition, soybean oil or peanut oil as lipid phase sample’s concentration 0.2% temperature 20℃ the emulsion was prepared. Then the emulsion was centrifuged and finally EC w4s calculated according to Definition 3. The results showed satisfying repeatability and reliability.

Key words: Soybean protein isolates, emulsification, emulsifying capacity