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Effect of high pressure treatment on ovotransferrin
- Acero-Lopez, Alexandra, Ullah, Aman, Offengenden, Marina, Jung, Stephanie, Wu, Jianping
- Food chemistry 2012 v.135 no.4 pp. 2245-2252
- Fourier transform infrared spectroscopy, denaturation, differential scanning calorimetry, enthalpy, fluorescence, high pressure treatment, hydrophobicity, pH, sulfhydryl groups, temperature
- High pressure processing of ovotransferrin was carried out to study the structural and physiochemical changes of ovotransferrin under various pressure levels. At pH 8 and pressures higher than 200MPa, a decrease in total sulfhydryl groups and an increase in surface hydrophobicity were observed along with a partial aggregation. A gradual shift of denaturation peak towards higher temperature was noticed up to 500MPa, leading to a total loss of the enthalpy of denaturation at pressures of 600 and 700MPa, where a significant decrease in intrinsic fluorescence was also observed. At pH 3, the ovotransferrin adopted a molten globule state, associated with a significant increase in surface hydrophobicity and reactive sulfhydryl content; structurally, no clear denaturation peaks in differential scanning calorimetry (DSC) were detected at any level of pressure treatment whereas a noticeable decrease in intrinsic fluorescence was evidenced up to 600MPa and then increased at 700MPa pressure treatment. Fourier transform infrared spectroscopy (FT-IR) revealed that the conformational structure were changed from helices, sheets, turns, and aggregated strand to mostly intermolecular β-sheets or aggregated strands at pH 8 at 200MPa but switched back to original structure at higher pressures.