Abstract:Effects of dry-heat treatment on the emulsifying and foaming properties of soy protein isolates at 60 ℃, 80 ℃, and 90 ℃ were studied. The results showed that the emulsifying activity of soy protein heated for 4 days increases to the maximum value and then decreased with further increase of the treatment time. The highest stability of the soy protein emulsion was achieved by dry-heat treatment of the soy protein for 4 days. The highest foaming overrun of soy protein (880%) was found by dry heat-treatment at 60 ℃ for 1 day, but further increasing the heating time resulted in a decrease in the foaming overrun. Besides, dry heat treatment at 80 ℃ and 90 ℃ significantly decreases the foaming stability of soy protein. SDS-PAGE analysis showed that dry heat treatment induced the polymerization of 7S subunits and partially 11S acid subunits of the soy protein.
