Chew on this! Understanding food structure transformation during oral processing and its impact on digestion
Ever wondered how chewing transforms your food? Be it a crunchy cracker, gooey cookie, or a lumpy porridge, our mouth is capable of transforming these different textures into a bolus that is safe to swallow. As we chew, bite-size chunks are reduced to smaller particles and mixed with saliva through complex and dynamic oral processes which result in the formation of a soft and smooth bolus ready to pass down the oesophagus into the stomach. These perceived changes in texture during oral processing not only affect our enjoyment of food, but also affects how easily nutrients are absorbed further down the gastrointestinal tract. Being able to understand the behaviour of different food types during oral processing is therefore fundamental to sensory and nutrition studies.
This project will investigate mechanisms governing bolus formation and identify critical characteristics that control subsequent digestion. What we perceive as food texture is explained by physical and chemical properties of food, and you will learn how to measure these using techniques such as rheology, particle sizing, and biochemical assays. You will also undertake a mastication study with human participants and develop new approaches to simulating bolus structures in the laboratory. You will then use established digestion models to study nutrient release from different bolus structures.
Despite its importance, there are still many unknowns when it comes to oral processing, and there is plenty of scope for the project to be taken in different directions, building on the foundational studies on food structure and bolus formation.
The project is highly relevant to the development of improved laboratory models of human digestion, enabled through engagement with an international researcher network. The work also has applications in the development of functional foods for metabolic/satiety regulation, oral delivery of therapeutics, and/or texture-modified foods for dysphagia (swallowing difficulties).
References
Butterworth PJ, Bajka B, Edwards CH, Warren FJ. Enzyme kinetic approach for mechanistic insight and predictions of in vivo starch digestibility and the glycaemic index of food. Trends Food Sci Technol 120, 254-264 (2022). https://doi.org/10.1016/j.tifs.2021.11.015
Cai M, Tejpal S, Tashkova M, Ryden P, Perez-Moral N, Saha S, Garcia Perez I, Serrano Contreras J I, Wist J, Holmes E, Bernal A, Dou B, Franco Becker G, Frost G, Edwards CH. Upper-gastrointestinal tract metabolite profile regulates glycaemic and satiety responses to meals with contrasting structure. [under review- Nat Metabol]
Kunath BJ, De Rudder C, Laczny CC, Letellier E, Wilmes P. The oral–gut microbiome axis in health and disease. Nat Rev Microbiol (2024). https://doi.org/10.1038/s41579-024-01075-5
Ravi A, Troncoso-Rey P, Ahn-Jarvis J, … Warren FJ. Hybrid metagenome assemblies link carbohydrate structure with function in the human gut microbiome. Commun Biol 5, 932 (2022). https://doi.org/10.1038/s42003-022-03865-0
Edwards CH, Ryden P, Mandalari G, Butterworth PJ, Ellis PR. Structure–function studies of chickpea and durum wheat uncover mechanisms by which cell wall properties influence starch bioaccessibility. Nat Food 2, 118–126 (2021). https://doi.org/10.1038/s43016-021-00230-y