doctorate: Study of the impact of varieties on the nutritional quality of peanuts

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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

Peanuts are an important source of protein used in the treatment of severe acute malnutrition, particularly through products like Plumpy'Nut® produced by the Nutriset group. The high protein content of peanuts makes them excellent candidates for creating affordable, protein-rich foods. However, among the 15,000 varieties of peanuts listed in international gene banks, only a small number are actively cultivated. Currently, there are very few, if any, peanut improvement programs focused specifically on enhancing the nutritional quality of proteins.

This thesis project aims to combine agronomic techniques with biochemical and nutritional approaches to identify and promote peanut varieties that have high nutritional quality based on their amino acid composition.

Scientific Objectives: The goal of this thesis project is to characterize and select peanut varieties that are well-suited to the climatic conditions of West Africa while also exhibiting the best protein quality. This selection will focus on a large collection of African peanuts, using the profile of essential amino acids as a benchmark. The chosen varieties should achieve a Protein Digestibility Corrected Amino Acid Score (PDCAAS) greater than 0.95 to comply with CODEX standards for ready-to-use therapeutic foods intended for managing severe acute malnutrition.

Originality of the Project: The innovative aspect of this project lies in screening peanut varieties based on their protein quality and utilizing the data generated in peanut breeding programs. To our knowledge, this approach has not previously been employed to assess the nutritional quality of peanut varieties or to develop high-quality nutritional foods, including but not limited to ready-to-use therapeutic foods. Consequently, this project will not only highlight the diversity of peanut varieties but also promote the sustainable use of natural resources in the fight against malnutrition in countries with vulnerable populations.

This thesis will be conducted in collaboration with research institutions in France and Senegal, providing the selected candidate with the following benefits:

• Access to the skills and infrastructure of ISRA/CERAAS for conducting agronomic trials and completing missing agronomic data for certain varieties in the African peanut collection.
  • Infrastructure and support from ISRA/CERAAS and CIRAD for preliminary biochemical analyses.
  • Expertise from the PNCA unit and the APReM team regarding amino acid and protein requirements for implementing research activities and experimental protocols.
  • Knowledge from the Department of Chemical Engineering and Applied Biology at the École Polytechnique Supérieure of UCAD.

The candidate will be primarily responsible for:

1- Setting up trials at the station to gather missing agronomic data from the African peanut collection available at ISRA/CERAAS.

A total of 1,200 peanut varieties from 10 African countries have been collected to form a reference African collection that represents current peanut agriculture in Africa. This composite reference collection has been genotyped using a high-density SNP chip, and a central collection of 300 varieties, showcasing the entire diversity of the African collection, has been established. These varieties were multiplied and distributed to all contributing countries, where they were evaluated for various agronomic traits, including biological nitrogen fixation and food quality characteristics. The analysis of these results identified subsets of varieties that exhibit both good agronomic performance and environmental stability, as well as varieties with high total protein, oil, oleic acid, sugar, tocopherol, iron, or zinc contents. The most relevant varieties in terms of protein, oil, oleic acid, iron, and zinc content have been utilized to develop bi-parental and multi-parental populations (6-way and 8-way).

In this thesis work, additional analyses will be conducted on these parental lines and other lines from the African core collection. Approximately thirty selected varieties will be cultivated in Senegal under two fertilization conditions, employing a complete randomized block design with three replications for each condition. The trials will be carried out under stringent rainfall conditions. Data will be collected and analyzed on several agronomic traits, including pod and seed weight per plot, 100-pod and 100-seed weight, and pod maturity. A ranking of the varieties will be established based on a multi-criteria index. The best-performing varieties in each fertilization condition will undergo nutritional analyses, with a special focus on selecting varieties that perform well under both fertilization conditions.

2- Screening and identifying peanut varieties with the best nutritional characteristics, specifically focusing on high protein content and low levels of antinutritional factors.

The top varieties selected in activity 1 will undergo further screening to confirm their protein content. It's important to mention that preliminary biochemical analyses have already been completed on all 300 varieties in the central collection. This biochemical data was used to calibrate models for predicting total protein and oleic acid content using Near Infrared Spectroscopy (NIRS). New NIRS spectra will be collected for the seeds of these varieties to refine the calibration of the prediction models.

3- Assess the nutritional quality of peanuts

3.1. The varieties of peanuts with the highest protein content will be selected for measuring their essential amino acid profiles using UPLC, a technique commonly employed in the PNCA unit. The resulting data will contribute to a database that includes the protein content and amino acid profile of each variety, along with additional information such as the place and year of production.

3.2. The peanut variety or varieties with the most promising amino acid profiles will be evaluated for their nutritional quality. The digestibility of these varieties will be assessed at the fecal level in adult rats housed in metabolic cages for 24 hours. On test days, the animals will be fed a diet containing the selected peanut variety, compared to a non-protein diet, allowing for the determination of endogenous nitrogen losses. Each test day will correspond to a different variety. By examining retained nitrogen and analyzing amino acids in the feces, we will identify which variety exhibits the best digestibility. A second experiment will evaluate the actual digestibility of the selected variety six hours after the ingestion of a test meal. During this period, feces and urine will be collected in the metabolic cages. At the end of the six hours, intestinal contents and blood samples will be collected for amino acid analysis to determine actual digestibility. These methods are standard in the unit for assessing the quality of protein sources and will help in determining the Protein Digestibility-Corrected Amino Acid Score (PDCAAS).

Your employer will be the French Center for International Cooperation in Agricultural Research for Development (CIRAD).

The project will take place in Senegal and France (Palaiseau).

You will be hosted at the PNCA unit in Palaiseau during your stay in France.

The projected timeline for the various stages of the project is detailed below:

 

Training and skills

Recommended education: Engineer or Master's degree in Agronomy, Human Nutrition, or International Agricultural Development

Desired knowledge: Knowledge in nutrition physiology, biochemistry, agronomy, and statistical analysis

Preferred experience: International experience in developing countries, internships, animal experimentation, biochemical assays

 Desired skills: Collaborative thinking, rigor and method, enthusiasm, commitment, honesty, autonomy, perseverance, resilience to failure, openness to others, and relational simplicity.

 

INRAE's life quality

By joining the CIRAD, you benefit from (depending on the type of contract and its duration)the working environment offered to the employees.

 

How to apply

I send my CV and my motivation letter