Tribology of Sustainable Protein Concentrates

University of Leeds Faculty of Environment

Prof Anwesha Sarkar

Sunday, May 31, 2026

Self-Funded PhD Students Only

About the Project

With increasing concerns about environmental sustainability, there is growing demand to use low carbon-intensive, sustainable, plant proteins, or at least partially replace conventional animal proteins such as whey or egg white proteins with plant proteins. However, one of the key barriers to consumer acceptance of plant protein-based foods is their undesirable mouthfeel, which often include: (a) astringency, hypothesised to result from oral lubrication failure of plant proteins [1] (b) grittiness, associated with protein-protein aggregation [2] causing high boundary friction and limited/ excessive surface adhesion, leading to undesirable mouthcoating during oral processing. Often highly purified plant protein isolates are used in food formulation and their delubrication performance has been relatively well-studied in the literature, where research is now evolved and focusing on understanding their behaviour in real food formulations [3]. However, the area which remains relatively less-explored is the tribological behaviour of plant protein concentrates, which naturally contain remnant polysaccharides and starches, and have not been through extensive fractionation and isolation processes. These inherent polysaccharides depending upon their structure may offer lubrication benefits, by modifying viscosity, while reducing additional costs and energy for protein purification. However, the mechanism by which these crude plant protein concentrate mixtures interact with oral surfaces to form tribological films remains poorly understood to date. Informed by advances in lubrication theory, this PhD project aims to systematically elucidate the mechanisms of boundary friction in plant protein concentrates. The project will investigate how these crude concentrates behave on deformable, model saliva-coated surfaces, focusing on surface roughness and wettability of oral surfaces. We will employ novel experimental and theoretical approaches, including: Dynamic friction measurements using 3D tongue-like deformable, weakly polar surfaces developed in our lab, which replicates the spatial distribution of papillae using 3D printing, soft lithography and model salivary coating [4];high-speed fluorescence imaging of tribological films; Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D) to assess affinity of these concentrates to oral films. Combining experimental data with indentation theory [5], we aim to understand how plant protein concentrates can form stable, lubricating tribofilms capable of supporting load, and to improve lubrication in food, diminishing astringency. There will be opportunities to investigate development of a novel theoretical framework from first principles and/or utilising statistical methods. This work will ultimately provide novel design rules for development of next-generation, cost-effective, sustainable plant protein-based foods. The PhD will offer an opportunity to collaborate with the National Alternative Protein Innovation (NAPIC).

For information on how to apply, please visit the institution website.

Funding Notes

This is not a funded project, but you can apply for funding separately. Self-funding students are also welcome to apply.

For more information please visit the institution website.

Where will I study?

University of Leeds

The University of Leeds is one of the largest research-intensive universities in the UK, offering a range of research degrees from Masters to PhDs (full-time or split-site), as well as professional doctorates. Our postgraduate researchers are a fundamental part of our vibrant research culture.

Project supervisors

Professor Anwesha Sarkar