Effect of xanthan gum on enhancing the foaming properties of soy protein isolate

The foaming properties of soy protein isolate (SPI) in the presence of xanthan gum (XG) were investigated. The XG solution alone did not exhibit any foaming ability. The optimal foaming properties were obtained from the SPI-XG dispersion that contained 0.1% SPI and 0.2% XG. This SPI-XG dispersion gave higher foaming capacity than that of SPI or egg white (P<0.05). The foam stability of SPI-XG dispersion was nine times higher than that of SPI and egg white (P<0.05). The SPI-XG foams were stable over wide ranges of ionic strength (0.1 to 1.0 M NaCl) and pH (4.5 to 9.0), and when heated (85°C, 1 h).