Thèse Valorization Of Grape By-Products Through Green Extraction And Lipid Encapsulation For Health Applications H/F Doctorat.Gouv.Fr

Établissement : Institut National Polytechnique de Toulouse École doctorale : SDM - SCIENCES DE LA MATIERE - Toulouse Laboratoire de recherche : LCA - Laboratoire de Chimie Agro-industrielle Direction de la thèse : Jean-François FABRE ORCID 000000018158958X Début de la thèse : 2027-09-01 Date limite de candidature : 2026-11-23T23:59:59 The proposed PhD project, titled 'Valorization of Grape By-Products through Green Extraction and Lipid Encapsulation for Health Applications,' aims to address the dual challenges of waste valorization and the development of functional ingredients for health and well-being by transforming grape pomace-a major by-product of the wine industry-into high-value bioactive compounds. This project aligns perfectly with the COFUND-BEST thematic 'Understanding and Promoting Healthy Living and Well-Being' by leveraging sustainable chemistry and innovative formulation techniques to create health-promoting products.
Grape pomace, which represents approximately 10-15% of the grape's weight during winemaking, is rich in polyphenols such as resveratrol, catechins, and anthocyanins, compounds widely recognized for their antioxidant, anti-inflammatory, and cardioprotective properties. However, their low bioavailability and instability limit their direct use in health applications. To overcome these challenges, the project will employ a multi-step approach combining green extraction, synergistic formulation, and lipid encapsulation. The Deep Eutectic Solvents (DES), particularly natural DES (NADES), will be used for the sustainable extraction of polyphenols from grape pomace. These solvents offer a green alternative to traditional organic solvents, reducing environmental impact while improving extraction efficiency.
The collaboration between the Laboratoire de Chimie Agro-industrielle (LCA) in Toulouse, France, and the ETSEA at the University of Lleida, Spain, ensures a complementary and interdisciplinary approach. ETSEA will focus on the design and synthesis of DES through molecular modeling (COSMO, DFT), as well as the chemical characterization of extracts using spectroscopy and chromatography methods. Meanwhile, LCA will lead the optimization of extraction protocols and the lipid encapsulation of polyphenols to enhance their stability and bioavailability, and the antioxidant evaluation of the extracts and formulations.
The project's expected outcomes include optimized DES extraction protocols, evidence of synergistic effects between polyphenols and other bioactive compounds, innovative lipid matrices for encapsulation, and prototypes of functional ingredients or food supplements with demonstrated health benefits. These results will not only advance scientific knowledge but also contribute to the circular economy by valorizing agricultural waste and creating sustainable, health-promoting products.
The project's strength lies in its interdisciplinary nature, combining theoretical chemistry, green extraction, and applied formulation, while fostering international collaboration between France and Spain. This approach ensures that the PhD student will gain comprehensive training in both fundamental and applied aspects of sustainable chemistry, preparing them for a career in academia or industry.
Wine byproducts are a major source of polyphenols, which are known for their protective effects against chronic diseases (diabetes, cancer, cardiovascular diseases, and neurodegenerative diseases). Traditional extraction methods are not very sustainable and are sometimes not very selective. DES, particularly natural ones (NADES), offer a green, safe, and effective alternative, allowing these compounds to be extracted and stabilized while reducing the environmental impact. Recent studies show that optimizing DES and related processes yields high-value-added extracts with proven antioxidant and anti-inflammatory activities. When combined with innovative encapsulation techniques (lipid-based systems, vesicles, protein-based or carbohydrate-based matrices), their efficacy and stability could be significantly improved. The main objectives of this thesis are to:
1. Efficiently extract polyphenols (resveratrol, catechins, anthocyanins) from wine-making byproducts using deep eutectic solvents (DES).
2. Study the synergistic effects between these polyphenols and other bioactive compounds (e.g., carotenoids).
3. Encapsulate the extracts in lipid matrices (vesicles, emulsions) to improve their stability and bioavailability.
4. Develop prototypes of dietary supplements or functional ingredients.
5. Evaluate the biological efficacy (antioxidant activity, bioavailability) of extracts and formulations.
1. Formulation and modeling of DES: rational selection of components (HBA/HBD) via molecular modeling (COSMO, DFT), synthesis, and physicochemical characterization.
2. Optimization of extractions: application of DES to different matrices (skins, seeds, stalks, pomace), optimization of parameters (temperature, time, ratio, power) using ultrasound, microwaves, and high-pressure homogenization.
3. Characterization of extracts: chromatographic analyses (HPLC, LC-MS/MS), determination of polyphenols, anthocyanins, and flavonols, stability testing.
4. Formulation of extracts: incorporation into lipid, protein, or carbohydrate matrices using spray drying, high-pressure homogenization, and ultrasonication
5. Bioactivity assessment: antioxidant (DPPH, FRAP), anti-inflammatory, and antimicrobial assays; bioavailability and cytotoxicity studies using cell models.
6. Valorization: identification of potential applications, functional testing (e.g., enzyme inhibition, food/cosmetic formulations).
8 Expected result