Adeline Boire
Unité BIA
Research Teams
ISD
Team members
Adeline Boire

Adeline Boire

ISD team

Adeline Boire

Adeline Boire

Research fellow

Email : adeline.boire[at]inrae.fr
Phone : (33) 2 40 67 40 83
Link Hal : https://cv.hal.science/adeline-boire
Link ORCID : https://orcid.org/0000-0002-3515-0194

CV_ADELINE BOIRE.pdf

Actual position and research subject

Current position: Research associate in the ISD team
Research theme: I study the structure and dynamics of plant protein assembly in relation to their function in real systems such as food matrices and plant seeds. I am interested in the interdisciplinary approach required for such investigations at the interface of biology, chemistry and physics.

Key words: plant proteins, assembly, interaction, hydration, intrinsic disorder, biophysics.

Specific topics of interest

Bioinformatic approaches to highlight plant proteins features

Animal- and plant-based proteins are present in a wide variety of raw and processed foods. They play an important role in determining the nutritional properties and the structure/texture of food. One of the current challenges is to replace, at least partly, animal-derived proteins with more sustainable alternatives, like proteins from plants, insects, and/or algae. This requires a comprehensive understanding of the effect of food processing, like temperature, shear, on the structure and dynamics of proteins assembly. We have initiated an in-silico exploratory study, within food proteins, to uncover potential drivers of their functional properties, such as solubility and aggregation. We built a reference database of food proteins, called FoodProteinsDB, that comprises protein sequences and their predicted physicochemical, biochemical, spectroscopic, and structural properties. Statistical analyses were carried out on the data to identify the main explanatory variables of the observed differences between the major classes of proteins and, interpret the observed differences/generics. One significant finding, from our initial analysis, was that amino-acid sequences of plant storage proteins are predicted to be more disordered than globular animal proteins, such as whey or egg proteins. Looking in more details in plant protein sequences reveals that most of them contain low complexity regions. Such domains comprised polar and/or charged amino acids which are mostly predicted disordered. We question the role of such sequence in the self-assembly of plant storage proteins in seeds and during food processes.

prediction.png

Predictions of backbone dynamics and hydropathy index of plant and animal storage proteins based on their amino-acid sequence. Data include rapeseed, pea, soy, wheat, sorghum, barley and maize proteins in green and milk and egg proteins in red. Degree of disorder was predicted using DynaMine application and the hydropathy index using ExPasy server based on Kyte & Doolittle method

Collaboration:

  • S. Pezennec, V. Lechevalier, C. Le Floch - Fouéré, A. Nicolas (UMR STLO, France),
  • M. Rakotoson (UMR SayFood, France),
  • H. Mameri (UMR IATE, France),
  • V. Lollier (UR BIA, France)

Here is a short sketch video on our bioinformatic approach:

Extraction, purification and characterisation of plant proteins

To validate the bioinformatic predictions, we are building up a library of purified proteins. This work is made possible by BIA’s technical facility dedicated to protein purification, and by the long experience of BIA in purifying plant proteins (Work from Popineau, Gueguen and co-workers). Over the past 7 years, we have optimised the purification protocol of rapeseed proteins, pea proteins, wheat gliadins and pigeon pea proteins. We also purified/characterized the two domains of gamma-gliadin, N-Ter and C-ter, by controlled hydrolysis; a model polypeptide of the N-ter domain of gliadins expressed recombinantly and two synthetic polypeptides of the N-ter domain.
Once purified, proteins are characterised using combination of biophysical tools (circular dichroism, fluorescent spectroscopy, SEC-MALS, SAXS ect.). As an example, we demonstrated the disordered nature of the N-terminal domain of γ-gliadin (Sahli et al., 2020). In addition, using ab initio modelling based on SAXS spectra, we obtained a low-resolution structural model of its C-terminal domain. Below, an example of characterisation of rapeseed cruciferin.

fig_saxs.jpg

Purification of rapeseed cruciferin and characterisation using SEC-SAXS and fluorescence spectroscopy.

 Collaboration:

  • V. Solé-Jamault, J. Davy, D. Renard (UR BIA,France)
  • H. Mameri (UMR IATE, France)
  • V. Nicoletti (UNESP, Brazil)
  • P. Roblin (LGC, France)

 Associated papers:

Micro-/millifluidic tools to probe protein solubility and assembly

We developped micro-/milli-fluidic screening tools to probe protein solubility under varying physico-chemical conditions. First, we have developed a simple tool based on millifluidics to screen phase diagram of proteins, pure or in mixtures with other biopolymers. It is used (i) to generate a homogeneous mixture of protein/buffer and/or protein/biopolymers in a short time (~s), (ii) to vary the composition of the mixtures by adjusting the flow rates, (iii) to control temperature within the range of 4 to 40°C , and (iv) to determine the turbidity of the drop by grey level analysis. The use of millifluidics reduced the amount of material of ten-fold and the experimentation time by a factor five compared to a conventional bulk approach. This set-up was used to explore functional synergies between proteins and polysaccharides as an example of application (Amine et al., 2019, Vakeri et al, under review). We also developed versatile microreactors to investigate in details the effect of the thermodynamic pathway on the solubility of plant proteins. These microreactors are used (i) to encapsulate “native-like” plant proteins in ideal solubilisation conditions that are usually not suitable for food application (basic pH, high ionic strength), (ii) to change solvent conditions with controlled buffer exchange and (iii) to probe the resulting phase transitions. These microreactors are based on semi-permeable liposomes produced by microfluidics.

micro.jpg

A. Milifluidic device to probe the phase separation of proteins, pure or in mixture, as a function of temperature and concentration (figure adapted from C. Amine’s PhD). B. Microreactors generated by microfluidics to tune the physical chemical environment in less than a minute and probe the dynamic of phase separation (figure adapted from R. Cochereau’s PhD).

Collaboration:

  • D. Renard, J. Davy, H. Voisin (UR BIA, France)
  • F. Jamme (Synchrotron Soleil)

 Associated papers:

Driving forces for liquid-liquid and liquid-solid phase separation

Coacervation, a thermodynamic phenomenon, induces the transformation of a homogeneous dispersion of macromolecules into two liquid phases through physicochemical modifications. An increase in attractive potential between identical proteins, achieved by altering pH or ionic strength, results in liquid-liquid phase separation. This reversible phenomenon has diverse applications, including protein fractionation and purification, active ingredient encapsulation, and potential uses for enhancing enzyme activities. Coacervation’s selectivity allows for efficient, selective, and reversible concentration of proteins, preserving conformation and reducing energy required for drying. Despite its applications, controlling coacervation can be challenging. Strong attractive interactions may lead to liquid-solid phase separation or aggregation. In our research projects, we aim to investigate the generic mechanisms governing the competition between coacervation and aggregation in protein/protein, protein/polysaccharide, and protein/polyelectrolyte mixtures. Understanding this competition is crucial for developing new applications based on phase separation.

coac.jpg

Protein coacervation and potential applications.

Collaboration:

  • D. Renard (UR BIA),
  • S. Bouhallab (UMR STLO),
  • A. Bouchoux (TBI)

 Associated papers:

Investigating the functional properties of plant proteins

Incorporating plant proteins into processed foods holds potential for increasing plant proteins consumption. As part of the European GreenProtein project, we conducted functional property screenings on Rubisco isolates derived from green waste. The concentrates exhibited excellent gelling and foaming properties. In collaboration with UMR IATE, we enriched cereal matrices with Rubisco, enhancing their protein content and improving essential amino acid profiles. Unlike other proteins, Rubisco did not adversely affect the mechanical properties of wheat-based dough, actively participating in the formation of the protein network (Ducrocq et al., 2020). Furthermore, we investigated the digestibility of Rubisco-enriched pasta and showed that the agregation state induced by RuBisCO enrichment modify the kinetics of nitrogen release (Ducrocq et al., under review). These multifaceted investigations contribute valuable insights into the techno-functional and nutritional aspects of incorporating plant proteins into food formulations. Recently, in collaboration, we also investigate the influence of fractionation on the functionality of plant proteins (PhD work of A. Locali-Pereira and J. Koomen).

rubisco.jpg

Investigation of RuBisCO-enriched wheat dough:
from the mechanical properties of dough to the molecular interactions (figure adapted from M. Ducrocq’s defense).

Collaboration:

  • V. Micard, M.-H. Morel (UMR IATE)
  • C. Berton-Carabin, A. Meynier, A.Riaublanc (UR BIA)
  • V. Nicoletti (UNESP, Brazil)

Associated papers:

  • Ducrocq et al. In vitro protein digestibility of RuBisCO-enriched wheat dough: a comparative study with pea and gluten proteins. Under review in Food and Function.
  • Ducrocq et al. (2020). Rubisco: A promising plant protein to enrich wheat-based food without impairing dough viscoelasticity and protein polymerisation. Food Hydrocolloids, 109, https://dx.doi.org/10.1016/j.foodhyd.2020.106101.
  • Locali-Pereira et al. (2024). Pre-treatment effects on the composition and functionalities of pigeon pea seed ingredients. Food Hydrocolloids, Accepted, https://doi.org/10.1016/j.foodhyd.2024.109923.
  • Locali-Pereira et al. (2023). Pigeon Pea, An Emerging Source of Plant-Based Proteins. ACS Food Science & Technology,3, 11, 1777-1799, https://doi.org/10.1021/acsfoodscitech.3c00268.

Modification date: 21 October 2024 | Publication date: 05 February 2024 | By: AK