0000000001317776
AUTHOR
Rémi Saurel
Protection of yeast cells in micro-organized shells of natural polyelectrolytes during drying process
The encapsulation techniques are applied in various fields and for various applications. The layer-by-layer self-assembly (LbL), one of the encapsulation techniques, is built by the electrostatic attraction between oppositely charged polyelectrolytes, and the topmost layer determines essentially the sur-face properties of the edifice. This technique offers several advantages (low cost, simplicity of process and equipment, biocompatibility and biodegra-dation, etc.). In this present paper, results of the protection of Saccharomyces cerevisiae yeast cells in microorganized shell of natural polyelectrolytes during dehydration process are reported. To apply the LbL method to individually encaps…
Rheological properties of thermal gels of pea and egg white protein mixtures
International audience
Thermal Denaturation of Pea Globulins (Pisum sativum L.)—Molecular Interactions Leading to Heat-Induced Protein Aggregation
The heat-induced denaturation and aggregation of mixed pea globulins (8%, w/w) were investigated using differential scanning calorimetry (DSC), SDS-PAGE, and size-exclusion chromatography (SEC-HPLC). DSC data showed that the pea proteins denaturation temperature (T(d)) was heating-rate dependent. The T(d) value decreased by about 4 °C by lowering the heating rate from 10 to 5 °C/min. The SDS-PAGE analysis revealed that protein denaturation upon heating at 90 °C was mainly governed by noncovalent interaction. The SEC-HPLC measurements indicated that low-denatured legumin (≈350-410 kDa) and vicilin/convicilin (≈170 kDa) globulins were heat-denatured and most of their subunits reassociated int…
Firming of fruit tissues by vacuum infusion of pectin methylesterase: Visualisation of enzyme action
; Apple pieces were vacuum-impregnated with either a pectin methylesterase (PME) and calcium solution or with water prior to pasteurization. Pasteurized apple pieces impregnated with PME and calcium showed a significantly higher firmness. Moreover, solid state C-13 NMR spectroscopy of apple cell wall residues revealed an increase of their molecular rigidity. Exogenous PME addition involved a decrease from 82% to 45% of apple pectin degree of methyl-esterification. Microscopic observations of apple slices immunolabelled with antibodies specific for pectins showed that (i) demethyl-esterification was more intense in the cell wall region lining intercellular spaces (demonstrating a key role f…
Effet de la variété sur les teneurs en métabolites secondaires dans les farines de pois
National audience
Native-state pea albumin and globulin behavior upon transglutaminase treatment
International audience; The behavior of pea albumin (Alb) and globulin (Glob) in their native state upon microbial transglutaminase (MTGase) treatment was studied. Only Glob was able to form a gel, at up to a 10% (w/w) concentration, with a minimum gelling concentration of 6% (w/w), and with a cross-linking degree of 25%. The most affected Glob subunits were convicilin (71 kDa), vicilins (55, 50, and 35 kDa), and legumin acidic subunit (40 kDa). In contrast, the legumin basic subunit (20 kDa) and vicilins of molecular weight less than 20 kDa remained mostly intact in all studied conditions. The cross-linking degree of Alb was 12%, which was not sufficient to form MTGase-induced gel. Major a…
Effects of heat treatment on rheological properties of pea and egg white protein mixtures
International audience; Partial substitution of animal protein by plant protein is a new opportunity to produce sustainable food for human beings. However, separated studies of plant protein and egg white cannot help to have a direct understanding of the complex structure in a mixed food product. In this work, we used low-denatured pea globulins (PG) in admixture with raw egg white (EW) to study the thermal and rheological behavior of the mixed systems submitted to heat treatment (>G’’) for all the protein samples whatever the pH. Higher storage modulus (G’) values for egg white indicated stronger elastic behavior as for the mixtures. From strain sweep experiments, the addition of PG in the…
Protection of living yeast cells by micro-organized shells of natural polyelectrolytes
International audience; Saccharomyces cerevisiae, a eukaryotic model organism, plays a key role in the oxidative stability of fermented products. In order to protect cells against environmental stresses, we report a method of modifying the cell surface architecture while maintaining the internal working properties of the system. The objective was to encapsulate living yeast cells in micro-organized polyelectrolyte shells using layer-by-layer (LbL) assembly. For the first time, the natural polyelectrolytes, β-lactoglobulin and sodium alginate, were alternately deposited on the surface of S. cerevisiae. Transmission electron microscopy coupled with immune-cytochemistry and scanning electron m…
1H NMR Spectroscopy As Tool To Study Transglutaminase Crosslinking Of Pea Globulin
Skiathos Island, GREECE - 30 May - 02 June 2013; International audience; A new method based on NMR spectroscopy was developed to detect the G-L (GlutamylLysine) isopeptide bonds formed by the enzymatic transglutaminase reaction. Because of thecomplexity of NMR signals of proteins due to their structures, the method was first developedon a model system (glutamine and lysine) to simplify the detection of the G-L residue. Andthen, the results were applied on the real protein matrix (pea globulin). MTG treatment ofmodel system led to the appearance of a new resonance on NMR spectrum which isoriginated probably from the ε-methylene protons of lysine residues covalently linked toglutamine. The co…
Applications of spray-drying in microencapsulation of food ingredients: An overview
International audience; Spray-drying process has been used for decades to encapsulate food ingredients such as flavors, lipids, and carotenoids. During this drying process, the evaporation of solvent, that is most often water, is rapid and the entrapment of the interest compound occurs quasi-instantaneously. This required property imposes a strict screening of the encapsulating materials to be used in addition to an optimization of the operating conditions. Likewise, if the encapsulated compound is of hydrophobic nature, the stability of the feed emulsion before drying should also be considered. Thus, spray-drying microencapsulation process must rather be considered as an art than a science…
Effect of high methoxyl pectin on pea protein in aqueous solution and at oil/water interface
International audience; The effect of the addition of high methoxyl pectin on the stability of pea protein isolate emulsions was investigated. Except for low pectin concentrations at acidic pHs where bridging flocculation occurred the addition of pectin improved emulsion stability to pH changes and depletion flocculation induced by maltodextrin addition. The mechanism of pectin induced stability was probed by measuring protein-pectin complex formation in solution, zeta potential of the emulsions droplets and the change in surface viscoelasticity on pectin addition. The phase diagrams of pectin-pea protein isolate in solution and pectin-pea protein-stabilized emulsions were established based…
Fermentation des protéines végétales : atouts organoleptique et nutritionnel
Référence : 201511122426; Du fait de l’augmentation de la population de la planète, la production de protéines pour l’alimentation des populations et l’évaluation de la qualité de ces protéines pour satisfaire les besoins de l’Homme pourraient devenir des questions majeures dans les décennies à venir pour l’ensemble du monde. Le développement de nouveaux aliments optimisant l’apport protéique d’origine végétale parait également important dans certaines situations (personnes âgées, sportifs…) où les besoins nutritionnels sont modifiés au plan quantitatif et qualitatif. De nombreux problèmes ont été identifiés suite à l’incorporation de protéines végétales dans nos aliments. En particulier, d…
Impact of processing conditions on functionality of powders prepared from mixed protein system
International audience; The projection of a global human population of around 9.5 billion by 2050 indicates that the demand for animal protein will double during this period. It seems therefore essential in regard to sustainability and food security to search for alternative protein sources that show nutritional and functional quality close to animal protein ones. In that respect, there is a growing interest in utilizing plant proteins as partial replacers of animal proteins in food. The reintroduction of plant proteins into our diet is a solution already envisaged by some vegetarian or flexitarian diets. In order to broaden this practice, one strategy is the use of protein mixes as an ingr…
Effect of pea proteins extraction and vicilin/legumin fractionation on the phase behavior in admixture with alginate
Abstract Soluble and natural mixed pea proteins (PP) were extracted from defatted pea seeds according to acidic precipitation (PPP) or ultrafiltration/diafiltration (PPDF) procedures. The isolates contained proteins with a low level of denaturation. Mixed pea globulins isolates presented quite similar solubility and thermal profiles, also a similar polypeptide composition. Vicilin/convicilin 7S (Vic) and legumin 11S (Leg) fractions were obtained by batch chromatography using a salt gradient for the elution. Several incompatible systems were built by mixing the pea proteins with an anionic polysaccharide (sodium alginate, SA), when biopolymers were both negatively charged. Most of mixtures e…
Aqueous two-phase system cold-set gelation using natural and recombinant probiotic lactic acid bacteria as a gelling agent
The present study aimed to entrap probiotic lactic acid bacteria (LAB) in a sodium alginate and sodium caseinate aqueous two-phase gel system. The natural acidifying properties of two therapeutic probiotic LAB were exploited to liberate calcium ions progressively from calcium carbonate (CaCO3), which caused the gelation of the co-existing phases. Bi-biopolymeric matrix gelation of GDL/CaCO3 or LAB/CaCO3 was monitored by dynamic rheological measurements, and the final gels were characterized by frequency dependence measurements and confocal laser scanning microscopy. Weak to strong gels were formed with an elastic modulus G' from 10 to 1.000Pa, respectively. After cold-set gelation of our sy…
VEggInInteractions protéines végétales –protéines de blanc d’œuf pour le développement d’ingrédients fonctionnalisés
compréhension des interactions entre protéines végétales et protéines de blanc d’œuf pour permettre l’amélioration de la « techno-fonctionnalité » des mélanges, notamment pour la stabilisation des mousses et émulsions, l’optimisation de ces fonctionnalités et l’identification des conditions permettant de limiter leur sensibilité aux traitements thermiques.
Protein aggregation induced by phase separation in a pea proteins–sodium alginate–water ternary system
Abstract The physicochemical properties of a native, globular plant protein–linear anionic polysaccharide aqueous system at 20 °C were investigated in conditions where biopolymers carry a net negative charge (pH 7.2, 0.1 M NaCl). The pea proteins–sodium alginate mixtures showed a phase separation mainly by thermodynamic incompatibility, characterized at both the macroscopic and microscopic scale. Phase diagram was established and confocal laser scanning microscopy (CLSM) provided accurate data on the microstructure morphology of the system, regarding its phase behavior. In admixture, sodium alginate induced a protein aggregation, certainly by a local depletion of the polysaccharide. Protein…
Improvement of the techno-functional properties of pea proteins by microfluidization
The use of pea (Pisum sativum (L.)) proteins in the food industry is still limited despite their good environmental sustainability, heath-oriented composition, reliable origin and stable price. However, one of the most important limitations is their low solubility which determines a number of their techno-functional properties. Microfluidization is a non-thermal emerging technology that may modify the structure and the techno-functional properties of pea proteins. Microfluidization combines high shear forces due to the stream speed and direction; impact forces from collisions with the walls and with the fluid itself; and turbulence inside the chamber. The objective of this work was to evalu…
Influence of impregnation solution viscosity and osmolarity on solute uptake during vacuum impregnation of apple cubes (var. Granny Smith)
Vacuum-assisted impregnation of pectinmethylesterase (PME) solution has been recognized as an efficient pretreatment to improve the firmness of heat-treated fruit. In order to improve the control of solute infusion into fruit pieces, the effect of the osmolarity and viscosity of vacuum impregnation solution on solute penetration and distribution was studied in 1.5 cm apple cubes, using model PME-based solutions containing sodium chloride and/or sodium alginate. While vacuum impregnation of either a viscous hypotonic or a non-viscous hypertonic solution infused solutes homogeneously into fruit pieces, the penetration of viscous hypertonic solutions was much lower, and PME or chloride infusio…
Monitoring of transglutaminase crosslinking reaction by 1H NMR spectroscopy on model substrates
International audience; A new method based on 1H NMR spectroscopy was developed for monitoring transglutaminase crosslinking reaction with model molecules (CBZ-Gln-Gly and N-α-acetyl-lysine). The transglutaminase reaction led to the appearance of new resonances on NMR spectrum as well as significant decrease in others. The new observed resonances, originated from newly formed ɛ-(γ-glutamyl)lysine isopeptide bonds, evidence the enzymatic reaction and allow to quantify the ɛ-(γ-glutamyl)lysine fragment. Moreover, the decrease in resonance intensity, originated from lysine, permit to determine the crosslinking degree. These results obtained by 1H NMR spectroscopy can be used as an alternative …
Environmentally eco-reasoned design process for functional yeast production and stabilization
Environmentally eco-reasoned design process for functional yeast production and stabilization. 3. European Congress of Applied Biotechnology (ECAB 3)
Partition of volatile compounds in pea globulin–maltodextrin aqueous two-phase system
International audience; This study is based on the assumption that the off-flavour of pea proteins might be decreased using the retention of volatile compounds by a mixture with another biopolymer. The partition of volatile compounds in an aqueous system containing pea protein and maltodextrins was followed under thermodynamic incompatibility conditions. Firstly, the phase diagram of the system was established. Then, the partition of aroma compounds between the phase rich in protein and the phase rich in maltodextrin was measured by SPME–GC–MS. There was a transfer of volatile compounds during phase separation. Variations of pH were also used to vary the retention of volatile compounds by p…
Size measuring techniques as tool to monitor pea proteins intramolecular crosslinking by transglutaminase treatment
International audience; In this work, techniques for monitoring the intramolecular transglutaminase cross-links of pea proteins, based on protein size determination, were developed. Sodium dodecyl sulfate polyacrylamide gel electrophoresis profiles of transglutaminase-treated low concentration (0.01% w/w) pea albumin samples, compared to the untreated one (control), showed a higher electrophoretic migration of the major albumin fraction band (26 kDa), reflecting a decrease in protein size. This protein size decrease was confirmed, after DEAE column purification, by dynamic light scattering (DLS) where the hydrodynamic radius of treated samples appears to be reduced compared to the control o…
The effects of sodium alginate and calcium levels on pea proteins cold-set gelation
Abstract A multi-scale investigation of pea proteins – alginate cold-set gels was proposed in this study. The gel preparation followed a two-steps procedure. Globular pea proteins were first denatured and aggregated by a pre-heating step. Sodium alginate was then added at different concentrations. Thereafter the in situ gelation process was induced at 20 °C using glucono-δ-lactone (GDL) and two calcium carbonate (CC) levels; calcium cations were released as the pH decreased. Small-amplitude rheology measurements (storage modulus G′) showed that stronger mixed gels were obtained than single-biopolymer solutions. Confocal laser scanning microscopy (CLSM) revealed phase-separating microstructu…
Le stress biotique, le décorticage ou la variété influencent la présence d'off-flavors dans la farine de pois
National audience
Design of biopolymeric matrices entrapping bioprotective lactic acid bacteria to control Listeria monocytogenes growth: Comparison of alginate and alginate-caseinate matrices entrapping Lactococcus lactis subsp. lactis cells
In order to design biopolymeric matrices entrapping bioprotective lactic acid bacteria (LAB) to control undesirable microorganisms growth in foods, the performances of alginate and alginate-caseinate (an aqueous two-phase system) matrices entrapping Lactococcus lactis subsp. lactis LAB3 cells were compared. Since efficient matrices should preserve the culturability and the antimicrobial activity of entrapped LAB3 cells for prolonged periods, they were both monitored for 12 days storage at 30 °C. Maximal cell density (∼109 CFU mL−1) was reached after 24 h whatever the matrix type. Then, the LAB3 cells population decreased: 107 and 106 CFU mL−1 were enumerated after 12 days in alginate-casein…
Formulation, process conditions, and biological evaluation of dairy mixed gels containing fava bean and milk proteins: Effect on protein retention in growing young rats
International audience; Food formulation and process conditions can indirectly influence AA digestibility and bioavailability. Here we investigated the effects of formulation and process conditions used in the manufacture of novel blended dairy gels (called "mixed gels" here) containing fava bean (Vicia faba) globular proteins on both protein composition and metabolism when given to young rats. Three mixed dairy gels containing casein micelles and fava bean proteins were produced either by chemical acidification (A) with glucono-δ-lactone (GDL) or by lactic acid fermentation. Fermented gels containing casein and fava bean proteins were produced without (F) or with (FW) whey proteins. The AA…
Formulation et procédés de fabrication des gels laitiers enrichis en globulines de fèverole : Impact sur la rétention protéique chez les rats jeunes en croissance
Introduction et but de l’etude L’impact environnemental et les risques pour la sante associes a la production et la consommation excessive de sources de proteines animales pourraient etre limites par l’augmentation de la part des proteines vegetales dans notre alimentation. Les proteines vegetales sont parfois deficitaires en certains acides amines (AA) essentiels. De ce fait, un melange de proteines animales et vegetales permettrait d’assurer une complementarite en AA repondant aux besoins de l’organisme. L’objectif de cette etude etait d’evaluer l’impact, sur la taille des proteines, de la formulation et des processus de transformation des gels laitiers enrichis en legumineuses et d’etudi…
Formulation et procédés de fabrication des gels laitiers enrichis en globulines de fèverole :Impact sur la rétention protéique chez les rats jeunes en croissance
Introduction et but de l’étude : L’impact environnemental et les risques pour la santé associés à la production et la consommation excessive de sources de protéines animales pourraient être limités par l’augmentation de la part des protéines végétales dans notre alimentation. Les protéines végétales sont parfois déficitaires en certains acides aminés (AA) essentiels. De ce fait, un mélange de protéines animales et végétales permettrait d’assurer une complémentarité en AA répondant aux besoins de l’organisme. L'objectif de cette étude était d'évaluer l'impact, sur la taille des protéines, de la formulation et des processus de transformation des gels laitiers enrichis en légumineuses et d’étu…
Interactions between proteins, phytic acid and calcium in Fava Bean concentrate
Interactions between proteins, phytic acid and calcium in Fava Bean concentrate
Utilisation of pectin coating to enhance spray-dry stability of pea protein-stabilised oil-in-water emulsions
International audience; In this study, development of pea (Pisum sativum) protein stabilised dry and reconstituted emulsions is presented. Dry emulsions were prepared by spray-drying liquid emulsions in a laboratory spray-dryer. The effect of drying on the physical stability of oil-in-water emulsions containing pea protein-coated and pea protein/pectin-coated oil droplets has been studied. Oil-in-water emulsions (5 wt.% Miglyol 812 N, 0.25 wt.% pea protein, 11% maltodextrin, pH 2.4) were prepared that contained 0 (primary emulsion) or 0.2 wt.% pectin (secondary emulsion). The emulsions were then subjected to spray-drying and reconstitution (pH 2.4). The stability of the emulsions to dry pro…
MOOC : "ProtéiNNOV : Protéines végétales et Innovation"
La prise de conscience d'une raréfaction des ressources en protéines animales dans les décennies à venir et la nécessité de produire plus durablement ces ressources alimentaires nous conduit à repenser aux autres sources de protéines, notamment les protéines d'origine végétale. Parmi les sources de protéines végétales, la plus employée comme substitut des protéines animales est le soja, mais le soja n'est pas la seule source de protéines végétales. Il est donc opportun de faire le point sur les autres sources de protéines végétales et sur leur utilisation. Le développement de nouveaux produits alimentaires riches en protéines végétales passe par la connaissance des atouts tant technologique…
Preferential localization of Lactococcus lactis cells entrapped in a caseinate/alginate phase separated system.
International audience; This study aimed to entrap bioprotective lactic acid bacteria in a sodium caseinate/sodium alginate aqueous two-phase system. Phase diagram at pH = 7 showed that sodium alginate and sodium caseinate were not miscible when their concentrations exceeded 1% (w/w) and 6% (w/w), respectively. The stability of the caseinate/alginate two-phase system was also checked at pH values of 6.0 and 5.5. Lactococcus lactis subsp. lactis LAB3 cells were added in a 4% (w/w) caseinate/1.5% (w/w) alginate two-phase system at pH = 7. Fluorescence microscopy allowed to observe that the caseinate-rich phase formed droplets dispersed in a continuous alginate-rich phase. The distribution of …
Properties of spray-dried food flavours microencapsulated with two-layered membranes: Roles of interfacial interactions and water
International audience; Engineering the interface of oil-in-water emulsion droplets with biopolymers that modify its permeability could provide a novel technique to improve flavour retention in dry powders. The objective of this study was to determine if volatile compounds were more retained in dry emulsions stabilized by pea protein isolate (PPI)/pectin complex than that stabilized by PPI alone. The retention of ethyl esters during spray-drying increased with decreasing volatility of the encapsulated compound and ranged from 28% to 40%. The addition of pectin to feed emulsions was quite effective in markedly improving the retention of the three studied flavour compounds. In our previous wo…
Preservation of viability and anti-Listeria activity of lactic acid bacteria, Lactococcus lactis and Lactobacillus paracasei, entrapped in gelling matrices of alginate or alginate/caseinate
In order to control undesirable microorganisms growth in foods, the performance of alginate and alginate-caseinate (an aqueous two-phase system) matrices entrapping lactic acid bacteria (LAB) (Lactobacillus paracasei LAB1 and Lactococcus lactis LAB3) was investigated. Polymeric matrices were initially loaded with Lcells at similar to 10(8-10) or similar to 10(4-6) CFU mL(-1), and were monitored, in liquid and gelled form (beads), for 12 days at 30 degrees C. In the liquid form, maximum cell density (similar to 10(9) CFU mL(-1)) was reached after 24 h whatever the matrix. Then, the Lpopulation decreased but remained higher in alginate-caseinate matrices: 10(7) and 10(6) CFU mL(-1) of LAB3 ce…
La génétique au service du goût : caractérisation de mutants pour l'accumulation de saponines et l'activité lipoxygènase dans la graines de pois (Pisum sativum)
International audience
Design of new sensitive α,β-unsaturated carbonyl 1,8-naphtalimide fluorescent probes for thiol bioimaging
International audience; We report herein an efficient synthesis of news naphtalimide-based fluorescent derivatives functionalized with an a,(3-unsaturated carbonyl group. Probes were synthesized from reaction of an amino-naphtalimide precursor with maleic anhydride. Photophysical study of fluorescent probes and cells labelling were performed, and showed that the reactive derivatives exhibit rich turn on fluorescence properties in presence of different biological thiol (Glutathione and Cysteine) making these systems a very promising way for thiol bioimaging.
CCDC 1054357: Experimental Crystal Structure Determination
Related Article: Nicolas Sok, Maria Nikolantonaki, Stephane Guyot, Thanh Dat Nguyen, Anne-Sophie Viaux, Franck Bagala, Yoann Rousselin, Florence Husson, Régis Gougeon, Rémi Saurel|2017|Sens.Actuators,B|242|865|doi:10.1016/j.snb.2016.09.171
CCDC 1054356: Experimental Crystal Structure Determination
Related Article: Nicolas Sok, Maria Nikolantonaki, Stephane Guyot, Thanh Dat Nguyen, Anne-Sophie Viaux, Franck Bagala, Yoann Rousselin, Florence Husson, Régis Gougeon, Rémi Saurel|2017|Sens.Actuators,B|242|865|doi:10.1016/j.snb.2016.09.171