The secondary structure of proteins in liquid, frozen, and dried egg-white samples: Effect of gamma irradiation treatment

In this study, the effect of gamma irradiation treatment on the secondary structure of the whole egg-white proteins was investigated. Liquid, frozen, and dried egg-white samples were subjected to gamma irradiation doses of 0, 1, 2, and 3 kGy. Protein secondary structures were determined by Attenuated Total Reflectance Fourier-Transform Infrared (ATR-FTIR) spectroscopy. In liquid egg-white samples, irradiation caused a conformational change from α-helix to disordered structure. Besides, a decrease in intermolecular β-sheet content was detected. On the other hand, no significant changes were observed in the secondary structure of frozen and dried egg-white samples. The significance of the results and their possible relationship to the viscosity decrease was also discussed. It was suggested that radiation-induced structural rearrangements may play a key role in the viscosity decrease.