Rheological Properties of Dairy Protein Gels

Dairy protein gels, formed predominantly from casein and whey proteins, underpin a vast array of fermented and acid-set products such as yoghurts, cheese and high-protein snacks. Gelation is driven by protein unfolding, aggregation and network formation, often initiated by acidification, enzymatic action or heat treatment. The resulting microstructure—a continuous protein matrix entrapping water and fat globules—governs key textural attributes: firmness, elasticity, viscosity and resistance to syneresis. Viscoelastic measurements reveal how storage modulus and loss modulus evolve with gel maturation, offering insight into elasticity and viscous dissipation. Shear-thinning behaviour, yield stress and thixotropy dictate flow under processing or mastication. Water-holding capacity and network connectivity determine whey separation and consumer acceptability, especially in low-fat or non-fat formats. Advances in microscopic and spectroscopic techniques have elucidated the relationship between microscopic protein clusters, pore size distribution and macroscopic mechanics. Optimising processing variables—heat profile, acidulant concentration, homogenisation pressure and stabiliser addition—enables tailored textures from creamy and spreadable to firm and sliceable, with applications extending to fat replacers, microgel dispersions and protein-enriched beverages. Such control is essential for sustainable product development, nutritional fortification and the global dairy industry’s response to health and environmental challenges.

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Rheological Properties of Dairy Protein Gels publication trend

The graph below shows the total number of articles in rheological properties of dairy protein gels across all publications each year (not limited to Nature Index journals).

Technical terms

Storage modulus (G′): A measure of elastic energy stored in a gel during deformation, reflecting its solid-like character.

Loss modulus (G″): A measure of energy dissipated as viscous flow during oscillatory deformation, indicating liquid-like behaviour.

Shear-thinning: Decrease in viscosity with increasing shear rate, common in dairy gels during stirring or pumping.

Syneresis: Expulsion of serum from a gel network, observed as whey separation in fermented dairy products.

Water-holding capacity (WHC): The ability of a protein network to retain water against gravitational or centrifugal forces, crucial for texture and yield.

Acid gelation: Network formation triggered by pH reduction, causing casein micelle destabilisation and protein aggregation into a gel matrix.

References

1. Application of whey protein emulsion gel microparticles as fat replacers in low-fat yogurt: Applicability of vegetable oil as the oil phase. Journal of Dairy Science (2022).
2. Water mobility and microstructure of acidified milk model gels with added whey protein ingredients. Food Hydrocolloids (2022).
3. Effects of Commercial Polysaccharides Stabilizers with Different Charges on Textural, Rheological, and Microstructural Characteristics of Set Yoghurts. Foods (2022).