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Updated: Apr 20, 2026

AFM and Microrheology in the Zebrafish Embryo Yolk Cell
Published on: November 29, 2017
Exploring the relationship between protein secondary structures, temperature-dependent viscosities, and technological
K Blume1, K Dietrich1, S Lilienthal1
1Center for Food Sciences, Institute of Food Toxicology and Analytical Chemistry, Department of Analytical Chemistry, University of Veterinary Medicine Hannover Foundation, Bischofsholer Damm 15, D-30173 Hannover, Germany.
Abstract:
Egg yolk and its main component, low-density lipoproteins (LDL), were consecutively pasteurised, optimally freeze-dried, and dispersed in various NaCl solutions (0-10%). Heat-induced changes in the protein secondary structures which accompanied viscosity-increasing aggregation processes were monitored using Fourier transform infrared spectroscopy (FTIR) to determine the intensities of intermolecular β-sheets (1622 cm(-1)) and results were compared with the temperature-dependent viscosities. Considerable changes in secondary structures observed after reconstitution of freeze-dried LDL had no detectable effect on the characteristic heat-induced viscosity curves but suggest that LDL plays a particular role in the unwanted gel formation of egg yolk after conventional freezing. For all egg yolk samples and all NaCl-containing LDL samples, the sigmoidal changes in the absorbance units vs. temperature curves corresponded with the first increase in heat-induced viscosity. Both analytical methods showed that the presence of ionic strength caused a shift in curve progressions towards higher temperatures, indicating increased thermal stability.
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