2022 年 28 巻 6 号 p. 479-487
A comparative study was carried out on the thermal stability of ovotransferrins (OTrfs) from chicken, duck, guinea fowl, Japanese quail, ostrich and turkey by differential scanning calorimetry (DSC), differential scanning fluorimetry (DSF) and turbidimetry. The average temperature at the denaturation midpoint in DSC (TmDSC) was 42.8 °C at pH 4.0, 63.8 °C at pH 7.0 and 59.4 °C at pH 9.0, and the differences in the TmDSC values between chicken and the other poultry, except ostrich, were less than 3.5 °C. The results of DSF were almost comparable to those of DSC. In an analysis of poultry OTrf solution turbidities, ostrich OTrf solution remained clear up to 95.0 °C at pH 4.0 and pH 8.0, while the others became turbid at around 40 °C at pH 4.0 and 60 °C at pH 8.0. Turkey, Japanese quail and duck OTrfs remained soluble at pH 9.0 up to 73.0 °C, 85.0 °C and 95.0 °C, respectively, though turbidity appeared up to 60 °C in the others. Such findings on the similarities and differences among poultry OTrfs should be significant for the utilization of poultry eggs other than chicken eggs since the thermal processes required for chicken egg products often depends on the behavior of heat-susceptible chicken OTrf.
