Effect of thermomechanical treatments promoting hornification, on the structure and functions of apple pomace

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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

Project description

The aim of this thesis is to understand the role played by polysaccharide-polysaccharide and polysaccharide-water interactions on the macroscopic properties of processed plant matter, in particular during technological pathways causing destructuration and hornification of cell-wall polysaccharides. More specifically, the aim is to understand, at a molecular scale, the effect of thermomechanical destructuring (cooking-extrusion) and restructuring (thermocompression) treatments of apple by-products on their macroscopic properties in food formulations, during ingestion and then digestion.

Context
Considering the role of food systems in addressing environmental challenges and the role of diet on prevalence of chronic non-communicable diseases, public policies at national and European level encourage establishment of sustainable agri-food systems from environmental, societal and economic perspectives [1]. These agri-food systems must be based on biocircularity and resource efficiency, promote healthy diets for all, and be made up of profitable and fair value chains [2]. The use of plant-based by-products rich in dietary fibres for the production of nutritionally value-added food ingredients could legitimately participate to such systems. Indeed, almost 2 million tonnes of fruit and vegetables are produced and processed per year in France, generating between 600,000 and 800,000 tonnes of by-products that are almost entirely lost [3,4,5], which represents an untapped potential of about 10,000 to 20,000 tonnes of dietary fibre, while the French population is chronically fibre-deficient [6]. Thus, valorisation of these by-products into food ingredients leveraging the nutritional functionalities of their fibres [7] could contribute to a virtuous and sustainable food economy, while generating a new value chain for French fruit and vegetable producers and processors [8].

Literature

[1] INRAE, ‘Les orientations 2023 d’INRAE’, INRAE Institutionnel. Available: https://www.inrae.fr/nous-connaitre/inrae-2030. 
[2] FAO/WHO, ‘Sustainable healthy diets. Guiding principles’, Rome, 2019. 
[3] France Agrimer, ‘LA FILIÈRE FRANÇAISE FRUITS ET LÉGUMES TRANSFORMÉS CHIFFRES-CLÉS 2021’, France Agrimer, 2023. 
[4] France Agrimer, ‘FRUITS ET LÉGUMES TRANSFORMÉS - Fiche filière’, France Agrimer, 2021. [Online]. Available: https://t.ly/QRbgi. 
[5] Bourcier, ‘Panorama statistique des fruits et légumes transformés’, France Agrimer, 2019. [Online]. Available: https://t.ly/5JXji. 
[6] EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA), ‘Scientific Opinion on Dietary Reference Values for carbohydrates and dietary fibre’, EFS2, vol. 8, no. 3, Mar. 2010. 
[7] Hasan et al. Bioresour. Bioprocess., 11(1), 1, 2024. 
[8] Romanazzi et al., ‘Innovation in Sustainable Management of Plant Diseases and Pests, and Effects on the Environment’, in The First Outstanding 50 Years of “Università Politecnica delle Marche”: Research Achievements in Life Sciences, S. Longhi, A. Monteriù, A. Freddi, L. Aquilanti, M. G. Ceravolo, O. Carnevali, M. Giordano, and G. Moroncini, Eds., Cham: Springer International Publishing, 2020, 601–616.

Doctoral contract funded by EUR Implantéus of Avignon University (50%) and INRAE's TRASNFORM department (50%). Net salary 1768€/month year 1, 1848€/month years 2 and 3.
Operational part funded by Carnot Qualiment under PommHorn project.
Experiments carried out in Avignon (SQPOV, UMR 408 INRAE/Avignon Université) and inToulouse (LCA, UMR 1010 INRAE/Toulouse INP-ENSIACET).
Possibility of adding paid teaching activities up to 64h/year from year 2.
Possibility of funding a presentation at an international conference (up to €1,000) and a short-term research stay in another laboratory (up to €3,000).

The SQPOV research unit is classified as a Restricted Access Zone (ZRR). Final admission is contingent upon obtaining approval from the relevant authorities for access to the ZRR.

Act no. 2016-483 dated 20 April 2016 pertaining to the code of conduct and public service employees’ rights and obligations recalls the core principles that apply to every individual employed by a public institution. All those who work at INRAE must carry out their duties with dignity, impartiality, integrity and probity, observe the obligation of neutrality, uphold the principle of secularism, and refrain from expressing their religious opinions during the performance of their duties. All employees contributing to INRAE’s work must treat equally all those they may interact with as part of their professional duties and respect their freedom of conscience and their dignity.

Training and skills

Required Qualifications :
- A Master’s degree (MSc, MEng) or equivalent in Food Science, Biochemistry, Biomolecular Chemistry, Biotechnology, Chemical Engineering, or a related field.
- International candidates are welcome, provided they meet the academic requirements for PhD admission.

Skills and Knowledge :
- Strong background in polysaccharides physico-chemistry and phenolic compounds chemistry.
- Knowledge of food and plant processing.
- Experience with analytical techniques (chromatography, spectroscopy, structural analysis) is a plus.
- Interest in interdisciplinary research combining chemistry, biotechnology, process engineering, food science and nutrition.

Desired Abilities :
- Autonomy, analytical thinking, and scientific rigorousness.
- Ability to interpret and analyze complex data.
- Willingness to work on both laboratory-scale and pilot-scale experiments.
- Good scientific communication skills (writing, presentations).

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

Application on adum platform :