Effects of pH-shifting treatments on oil-water interfacial properties of pea protein isolates: Identification and quantification of proteins at interfacial protein layer

The process, known as alkali pH-shifting treatment, was able to improve the emulsifying capacity of pea protein isolates (PPI). In this work the mechanism was further investigated. The relative quantities and types of interfacial adsorbed proteins with alkali pH-shifting treatments were determined by quantitative proteomic. For the pH 10-shifting treatment, the relative quantities of legumins and albumins were increased at the oil-water interface, and the increases of small molecule albumins were resulted from their faster adsorption rates. In contrast, the relative abundances of vicilins were decreased by the effect of competitive adsorption at the interface. Further these quantitative results were verified with the interface rheology of the major components of PPI. The stronger emulsifying activity of pH 10-shifting-treated 11S might play a key role in the whole emulsifying behavior of pH 10-shifting-treated PPI. These results could promote the potential development of theory of plant protein stabilized emulsions.