Abstract:

Effects of pulsed electric field (PEF) treatment on size distribution of soy protein isolate (SPI) polydispersion system, 7S dispersion system and 11S dispersion system were investigated in this study. The results indicated that the average protein granule size significantly decreases with the increase of electric field strength. It was demonstrated that the polydispersibility index (PDI) values of SPI polydispersion system and 7S monodispersion system both increase firstly and then decrease with the increase of electric field strength, but they are higher than those of the untreated systems. On the contrary, the PDI value of 11S dispersion system decreases at first and then increases with the increase of electric field strength. Meanwhile, the quantity of protein granules in the range of 20 to 100 nm increases with the increase of electric field strength for all the tested samples, which implied that PEF treatment can greatly affect the size distribution of protein granule, thus enhance its colloid properties.

Key words: pulsed electric field (PEF), oybean protein isolate (SPI), granule size distribution, dispersibility index (DPI)