Abstract:To compare differences in bovine serum protein damage following sterilization by γ rays and electron beam irradiation, bovine serum was irradiated with 0~50 kGy and protein concentration, turbidity, and hydrophobicity were determined. The secondary structure and thermal stability of the albumin purified from this bovine serum were analyzed. The results showed that the protein concentration decreased, and the turbidity and hydrophobicity increased. And the changes induced by electron beam irradiation were smaller than those induced by γ rays. At the threshold dosage of 10 kGy, the α-helical content of albumin had increased and thereafter decreased, and β-fold content first decreased and thereafter increased, with ranges of change of 0~15.2% and 40.6~52.4%, respectively. The content of random coils always showed an increasing trend. After irradiation, the DSC plot of the albumin fraction from the bovine serum showed an exothermic peak with a prolonged time, and the peak temperature increased with increased dose (77.4 ℃ to 79.1 ℃); electron beam irradiation showed the opposite trend. In the GPC plot, the miscellaneous albumin peaks exhibited widening after irradiation. This shows that the interaction between the radiation and the electron beam causes crosslinking reactions and degradation of bovine serum, which disrupts the secondary structure of albumin and exposes the hydrophobic groups of bovine serum albumin to the exterior, increasing turbidity and decreasing concentration. No significant difference between the electron beam and γ rays was found at normal temperatures.
