Creating high-performance lubricating microgels from sustainable plant proteins

Introduction

The resource-intensive meat industry contributes significantly to food-related emissions, making plant protein consumption crucial. However, the adoption of plant proteins faces a hurdle due to their astringent taste caused by poor lubrication performance. This study introduces a solution: converting plant proteins into cross-linked microgels. This innovation substantially improves lubricity, demonstrated through various analyses including tribology, atomic force microscopy, and rheology. The microgels significantly reduce friction and replicate the lubrication of oil/water emulsion. This advancement opens avenues for developing healthier, tastier, and environmentally sustainable foods using plant protein microgels.

Material and Methods

The adoption of sustainable plant proteins in food is hindered by their undesirable mouthfeel, which poses a challenge to consumer acceptance and the transition to plant-based diets. To address this, the study introduces a method to enhance the lubrication of plant proteins by transforming them into physically cross-linked microgels. Two common plant proteins, pea and potato, were used to validate this concept. The microgels were created by hydrating, gelling, and homogenizing the proteins, resulting in various microgel types differing in protein concentration and volume fractions.

Through a combination of techniques including DLS, AFM, and rheology, the study confirms the formation of sub-micron sized microgels with controlled size and stability. These microgels exhibit Newtonian behavior and desirable properties compared to the highly aggregated and shear-thinning native proteins. The lubrication performance of these microgels was rigorously tested using various methods, including biomimetic surfaces resembling the human tongue. The results demonstrate that the microgels offer excellent lubrication properties. Notably, PPM15, PoP5, and PPM7.5:PoPM5 microgels achieved a significant reduction in friction compared to native proteins, even rivaling the lubrication performance of an oil/water emulsion without the use of lipids. The study also uncovers the mechanism behind the enhanced lubrication provided by the microgels. Adsorption measurements, theoretical modelling, and relative indentation calculations shed light on their viscoelastic properties, swelling behavior, and load-bearing ability. This behavior contrasts with native plant proteins that tend to aggregate and exhibit higher friction. While the study provides comprehensive insights into the benefits of plant protein microgels for improved lubrication and mouthfeel, it emphasizes the need for further research to fully understand their friction-mediated sensory analysis. Overall, the findings offer a promising avenue for developing more palatable and functional plant-based foods.

Conclusion

Considering increasing sustainability concerns, the rise in vegetarianism, global protein malnutrition, and inequality, the future global population must embrace plant-based proteins. While plant applications are key in food development, they currently face limitations including unfavourable mouthfeel and inadequate functionality, among other barriers. By utilizing a range of experimental and theoretical methods, this study establishes that micro-gelation presents a feasible approach to enhance the lubrication, application, and stability of plant proteins in food products. Converting native plant proteins into microgels emerges as a straightforward solution to address friction-related challenges. The success of this mechanistic approach, combined with future sensory studies, is poised to facilitate a swift transition from animal to palatable plant protein-based diets. This transition holds the potential to contribute to planetary health by addressing the pressing issues of sustainability, nutrition, and equitable access to food sources.

Reference

[1] Kew, B., Holmes, M., Liamas, E., Ettelaie, R., Connell, S.D., Dini, D. and Sarkar, A., 2023. Transforming sustainable plant proteins into high performance lubricating microgels. Nature Communications, 14(1), p.4743.