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24, chemin de Borde Rouge –Auzeville – CS52627
31326 Castanet Tolosan CEDEX - France

Dernière mise à jour : Mai 2018

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Polyphenols, Reactivity, Process (PRP)

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               Context and Objectives - Research lines - Methods and Equipment


Team leader: Sylvain Guyot

Color and taste

Taste and color !

What are the origins of taste and the color of apple juice and cider ? Apple juice and cider offer a variety of colors and flavors. Bitter or sour, how to modulate the taste of juice? How to form color when the transformation of apple juice?

Discover the origin of the taste and color of cider and apple juice through the work done by the team Polyphenols, Reactivity and processes ( eg research cider ).

Permanent team members:

Researchers  and engineers:   Sophie Guilois, Sylvain GuyotJean-Michel Le Quéré

Technicians and assistant engineers:  Agnès Gacel, Gildas Le Bail, Nathalie Marnet, Hélène Sotin

Temporary staff members:

Mariana Castillo-Fraire (phD student), Héloïse Monier (CDD engineer)

Thesis defended recently:

Mélanie Millet (2018)

Alumni :

Xiaoxi Yu (post-doc)

Context and Objectives

The main objective of the PRP team is to know and understand the role and implications of phenolics and tannins in particular that during the development of liquid foods , fermented or otherwise, from fruit processing related organoleptic and nutritional qualities of finished products. Apple and cider are taken as preferred models. The research focuses on the mechanisms of enzymatic oxidation of polyphenols , nature and fate of phenolic oxidized species by incorporating the complexity of the raw material ( including interactions with biopolymers fruit ) and technologies implemented in the various operations unit of processing fruit. Our approach involves biochemistry, reaction chemistry and physical chemistry of polyphenols. It is based on a round trip between the permanent solution model and the real environment with the aim of prioritizing influential factors on the mechanisms and kinetics of the oxidation of phenolic compounds. Among these factors we include in particular the genetic variability and eco- physiological raw material in terms of polyphenols and polyphenol oxidase activity and the availability of oxygen. Today, the expected outputs of this research are more focused on a better color control , colloidal stability and excitement.

Specific context of the PRP team : the team is located at the INRA site the Rheu ( INRA Rennes ) . In addition, the PRP team formalizes its relationship with the cider industry through close collaboration with the French Institute Productions Cider (Institut Français des Productions Cidricoles, IFPC) which is reflected in his involvement in the UMR Technology Novacidre . In addition, the analytical needs of the team (HPLC , UPLC , GC , MS, UV ... ) are provided largely through the Plateau P2M2 which PRP team is co-founder.


Research lines

Two scientific priorities are considered:

  • Develop mechanistic and kinetic approaches to enzymatic oxidation of polyphenols and study the interactions between phenolic molecules oxidized or not and macromolecules (polysaccharides and proteins)
  • Enhance the data acquired in the field of polyphenols in a process of " knowledge assembly " category


Methods and Equipment

  • Techniques of sample preparation, biochemistry and chemistry applied to extractive phenolic compounds and cell wall polysaccharides
  • Techniques for measuring enzymatic activity type and polyphenoloxidase polysaccharidase
  • Separation techniques polyphenols analytical scale , semi -preparative and preparative : HPLC , UPLC , GC , CPC, low pressure chromatography
  • Detection techniques and structural characterization of phenolic compounds with or without chromatographic coupling : UV-Visible spectrometry microplate , mass spectrometry, electron impact (GC coupling) , ESI- Ion Trap , ESI- triple quadrupole ESI- QTOF)
  • Manufacturing techniques of apple juice and cider : Pilot hall equipped with washers, rasps , different presses, modules filtration and centrifugation , controlled variable volume fermenters* ( *material partly owned by the ECI but PRP accessible through Nova2cidre UMT)

NB : Most of the analytical equipment is integrated in the analytical platform P2M2



Polyphenols, tannins, polysaccharides, nitrogen compounds, fruits, oxidation, oxidases, mass spectrometry, enzymes, interactions, apple cider