Inhibition effect of natural deep eutectic solvents on frozen egg yolk gelation: Rheological properties, protein...

Egg yolk undergoes a pronounced increase in viscosity after freezing, which commonly referred to as ice-induced gelation. Therefore, a natural deep eutectic solvent (NADES) composed of xylose and choline chloride was developed. Result showed that NADES reduced the viscosity coefficient of frozen-thawed yolk from 443 to 58.2 Pa·Sⁿ. Turbidity decreased from 1.69 to 0.29, absolute ζ-potential decreased from 5.31 to 4.34 mV, average particle size demonstrated a 65.7% decrease, indicating NADES mitigates protein aggregation during freezing. Low-field nuclear magnetic resonance showed that T₂₁ relaxation time increased from 16.8 to 18 ms. Indicated the incorporation of NADES suppresses water migration. Raman and differential scanning calorimetry revealed that the addition of NADES intensified the characteristic peaks of frozen yolk, reduced the melting enthalpy of fusion to 78.3 J/g, and lowered the melting temperature to -1.73 °C. In summary, this NADES functions as a promising antifreeze agent capable of mitigating cold-induced gelation in yolks.