Tribological and Rheological Properties of Food Systems

Tribological and rheological properties govern the mechanics of food in oral processing, shaping texture, mouthfeel and consumer acceptance. Rheology describes a food’s flow and deformation under shear or extensional forces, encompassing viscosity, viscoelastic moduli and yield stress, whereas tribology evaluates frictional interactions between the food and soft oral surfaces. Together these disciplines reveal how microstructure, composition and deformation regimes—boundary, mixed and hydrodynamic lubrication—affect sensory attributes such as creaminess, slipperiness and astringency. Advances in microgel technology, emulsion design and protein engineering have enabled tunable viscosity modifiers and bio-lubricants that replicate or surpass traditional fat lubrication while meeting nutritional and sustainability goals. Understanding these interlinked phenomena is essential for formulating low-fat products, plant-based alternatives and tailored mouthfeel profiles with predictable sensory outcomes.

Research from Nature Portfolio

Recent studies have demonstrated that plant proteins can be transformed into physically cross-linked microgels to enhance lubrication in the oral cavity. By combining tribological measurements on biomimetic tongue surfaces, rheological characterisation and atomic force microscopy with numerical modelling, these non-lipidic microgels reduce boundary friction by an order of magnitude compared to native proteins and replicate the lubrication performance of conventional oil-in-water emulsions. Building on this platform, the self-assembly of plant protein protofilaments within a biopolymeric hydrogel has yielded superlubricity under moderate to high contact pressures. Multiscale experimental analyses alongside molecular dynamics simulations reveal that hydrophobic interactions anchor protofilament patches to the surface while the surrounding hydrogel matrix provides hydration lubrication, achieving friction coefficients approaching 0.00007 and establishing a blueprint for eco-friendly high-performance food lubricants.

Tribological and Rheological Properties of Food Systems publication trend

The graph below shows the total number of articles in tribological and rheological properties of food systems across all publications each year (not limited to Nature Index journals).

Technical terms

Tribology: The study of friction, lubrication and wear occurring between interacting surfaces.

Rheology: The science of deformation and flow of matter under applied stress, encompassing viscosity and viscoelasticity.

Microgel: A colloidal network of cross-linked polymer or protein particles that can swell in water, used to modulate texture and lubrication.

Boundary lubrication: A regime in which surfaces are separated by a thin film of lubricant, and friction is dominated by surface interactions.

Elastohydrodynamic lubrication: A regime in which high contact pressures and elastic deformation generate a lubricating film that prevents asperity contact.

Hydration lubrication: A mechanism in which tightly bound water layers or hydrophilic networks reduce friction by providing a lubricating boundary film.

References

1. Transforming sustainable plant proteins into high performance lubricating microgels. Nature Communications (2023).
2. Self-assembly of sustainable plant protein protofilaments into a hydrogel for ultra-low friction across length scales. Communications Materials (2024).
3. Influence of thickeners (microfibrillated cellulose, starch, xanthan gum) on rheological, tribological and sensory properties of low-fat mayonnaises. Food Hydrocolloids (2023).
4. Surface adsorption and lubrication properties of plant and dairy proteins: A comparative study. Food Hydrocolloids (2021).