Probing the sol–gel transition of egg white proteins by pulsed-NMR method

The utility of pulsed NMR spectroscopy as a convenient means to monitor a sol–gel transition during heat-induced gelation of egg white proteins was investigated. This is based on the notion that, regardless of the mechanism of gel formation, the transition from sol to a gel state in such system is accompanied by the appearance of solid-like domain and a concomitant increase in the NMR signal attributed to protons in the solid-like fraction. The transition from sol to a gel state was clearly evident when the egg white was held isothermally at 80 °C in a water bath. The effects of some sugars and chemical cross-linking agents were also investigated in order to establish whether the method is capable of differentiating the relative effect of the chemicals on the kinetics of the gelation process. The results showed that pulsed NMR has a potential value as a complementary method to study sol–gel transition of food biopolymer.