Egg yolk as a model for gelation: from rheometry to flow physics

TL;DR

This study provides a comprehensive rheological analysis of egg yolk as a model for gelation, introducing novel visualizations and methods to better understand the critical gel point and flow behavior.

Contribution

It offers a detailed dataset and visualization techniques linking rheology with flow behavior, advancing understanding of sol-gel transitions in egg yolk.

Findings

Identified critical gel points using multiple rheological methods.

Visualized flow behavior near gelation transitions.

Highlighted timescale dependencies in gelation detection.

Abstract

Egg yolks are an excellent model for studying sol-gel transitions, particularly the power law viscoelasticity that defines the critical point of gelation. However, prior studies lack comprehensive datasets and fail to visualize flow behavior linked to temperature and time-dependent linear and nonlinear rheology. Here we present a detailed dataset characterizing egg yolk viscoelasticity across temperature, time, and forcing amplitude using oscillatory shear, step strain, step stress, and constant high strain rate. Novel protorheology visualizations link rheological properties with observable flow behavior. Our findings highlight the nuanced determination of the critical gel point, emphasizing observation timescale dependencies. We compare methods to identify critical temperatures for gelation, including power law viscoelasticity, moduli crossover, diverging zero-shear viscosity, and emerging equilibrium elastic modulus, while visualizing flow consequences near these transitions. Egg yolk is an accessible non-toxic material relevant to the physicist and the chef alike, making it ideal for understanding the rheology of critical gels. By integrating protorheology photos and videos with rigorous rheometric data, we deepen the understanding of critical gels, with broader impacts for teaching and modeling sol-gel transitions.