PhD position OT-25818
Investigation of the effects of gastric pH on in vitro gastrointestinal digestion of solid food particles using innovative magnetic resonance imaging (MRI) approaches
35043 Rennes
INRAE presentation
The French National Research Institute for Agriculture, Food, and Environment (INRAE) is a major player in research and innovation. It is a community of 12,000 people with 272 research, experimental research, and support units located in 18 regional centres throughout France. Internationally, INRAE is among the top research organisations in the agricultural and food sciences, plant and animal sciences, as well as in ecology and environmental science. It is the world’s leading research organisation specialising in agriculture, food and the environment. INRAE’s goal is to be a key player in the transitions necessary to address major global challenges. Faced with a growing world population, climate change, resource scarcity, and declining biodiversity, the Institute has a major role to play in building solutions and supporting the necessary acceleration of agricultural, food and environmental transitions.
Work environment, missions and activities
Solid food enters the stomach as particles between 0 and 5 mm in diameter. Depending on their structural and compositional properties, digestion of these particles can be limited by the diffusion of digestive enzymes within them, the resistance of microstructures to enzymatic attack (e.g. gluten, cell walls) or by pH conditions unfavourable to enzyme activity (buffering effect). The ability of MRI to characterise the composition and structure of food at different scales (from molecules to particles) in a non-invasive and non-destructive way makes it a method of choice for monitoring digestion kinetics and improving our understanding of the mechanisms involved in the disintegration of solid food particles.
The aim of this thesis is to study the mechanisms that limit the degradation of solid food particles and the release of their nutrients during in vitro digestion under MRI. Particular attention will be paid to the influence of gastric acidification kinetics, which are known to be highly variable between individuals (inter-individual variability or variability induced by the use of proton pump inhibitors), on gastrointestinal digestion kinetics. Firstly, the matrix effect of Emmental cheese, with its strong buffering effect, will be studied using 2 devices to study phenomena at the scale of a mixture of particles on the one hand, and a single particle on the other. Secondly, the matrix effect of apples, as a model of fleshy fruit, will also be studied.
The experiments will be performed on the 1.5 T whole body MRI imager (SOLA, Siemens) using original devices that has already been validated for performing in vitro digestion under MRI.
The PhD student will be integrated into the teams of the two research units, OPAALE and STLO (about 2 km apart), where all the equipment required for the thesis is available. The thesis will be co-supervised by: Thesis supervisor: Maja Musse, researcher INRAE, UR OPAALE, IRM-Food team Thesis co-supervisor: Steven Le Feunteun, researcher INRAE, UMR STLO, BN team https://eng-opaale.rennes.hub.inrae.fr/research/research-teams/irm-food
Training and skills
The ideal candidate will be a physicist or physical chemist with basic knowledge of MRI/NMR physics and signal/image processing. Skills or interest in applications in food science, nutrition and/or biology would also be appreciated. A good level of English is also required.
INRAE's life quality
By joining our teams, you benefit from (depending on the type of contract and its duration):
- up to 30 days of annual leave + 15 days "Reduction of Working Time" (for a full time);
- parenting support: CESU childcare, leisure services;
- skills development systems: training, career advise;
- social support: advice and listening, social assistance and loans;
- holiday and leisure services: holiday vouchers, accommodation at preferential rates;
- sports and cultural activities;
- collective catering.
How to apply
I send my CV and my motivation letter
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