Catherine Joly - Academia.edu (original) (raw)

Papers by Catherine Joly

HAL (Le Centre pour la Communication Scientifique Directe), Aug 11, 1997

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

HAL (Le Centre pour la Communication Scientifique Directe), Nov 8, 2001

Journal of Raman Spectroscopy, 2006

Surface‐enhanced Raman spectroscopy (SERS) was used in this work to obtain highly detailed spectr... more Surface‐enhanced Raman spectroscopy (SERS) was used in this work to obtain highly detailed spectra of artists' red lake pigments and colorants. In the past, Raman spectroscopy has been successfully employed to identify many pigments and modern synthetic dyes. Unfortunately, red lake pigments and dyes commonly employed in artistic production from antiquity to the mid‐nineteenth century are often extremely fluorescent, making identification with Raman spectroscopy difficult or impossible. This work presents an innovative SERS technique that quenches fluorescence, significantly enhances the weak Raman scattering effect, and requires very little sample material and minimal sample handling. A silver island film (AgIF), approximately 6–8 nm thick, is deposited on the substrate by electron beam (e‐beam) deposition. The SERS‐active surface is then analyzed with a confocal dispersive Raman microscope, at an excitation wavelength of 632.8 nm. Reference materials including the synthetic dy...

Foods

Fresh fish is a perishable food in which chemical (namely oxidation) and microbiological degradat... more Fresh fish is a perishable food in which chemical (namely oxidation) and microbiological degradation result in undesirable odor. Non-processed fish (i.e., raw fish) is increasingly commercialized in packaging systems which are convenient for its retailing and/or which can promote an extension of its shelf-life. Compared to fish sent to its retail unpackaged, fish packaging results in a modification of the gaseous composition of the atmosphere surrounding it. These modifications of atmosphere composition may affect both chemical and microbiological degradation pathways of fish constituents and thereby the volatile organic compounds produced. In addition to monitoring Total Volatile Basic Nitrogen (TVB-N), which is a common indicator to estimate non-processed fish freshness, analytical techniques such as gas chromatography coupled to mass spectrometry or techniques referred to as “electronic nose” allow either the identification of the entire set of these volatile compounds (the volat...

Mathématiques

Des regles de plus en plus restrictives entrent en vigueur pour les materiaux au contact des alim... more Des regles de plus en plus restrictives entrent en vigueur pour les materiaux au contact des aliments. Elles incluent aujourd’hui une obligation de tracabilite au cours de la transformation et formulation de ce type de materiaux. Pour atteindre de tels objectifs, la direction generale de la Protection de la sante et du consommateur encourage l’utilisation de la modelisation pour predire le risque de contamination des aliments emballes. Des methodes et les techniques de modelisation existent pour evaluer le risque de contamination des aliments : demonstration de la conformite, conception de materiaux surs, veille sanitaire, orientation de politiques de controles. L'approche est meme conduite jusqu'a l'evaluation probabiliste de l'exposition chronique du consommateur sur la base de donnees de contamination simulees.

Le Centre pour la Communication Scientifique Directe - HAL - memSIC, Nov 8, 2001

SSRN Electronic Journal, 2022

FEMS Microbiology Letters, 2021

The membrane-damaging activities of four phenolics chosen for their bactericidal activity against... more The membrane-damaging activities of four phenolics chosen for their bactericidal activity against Staphylococcus aureus CNRZ3 were investigated: 5,7-dihydroxy-4-phenylcoumarin (DHPC), 5,8-dihydroxy-1,4-naphthoquinone (DHNQ), epigallocatechin gallate (EGCG) and isobutyl 4-hydroxybenzoate (IBHB). Staphylococcus aureus CNRZ3 cells, as well as model liposomes mimicking its membrane phospholipids composition, were treated with each phenolic at its minimal bactericidal concentration. Membrane integrity, intracellular pH and intracellular esterase activity were examined by flow cytometric analysis of S. aureus cells stained with propidium iodide and SYTO® 9, 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl ester, and 5(6)-carboxyfluorescein diacetate, respectively. While intracellular pH was affected by the foyr phenolics, only DHNQ and to a lesser extent EGCG, caused a loss of membrane integrity. Flow cytometric analysis of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)...

European Polymer Journal, 2016

Solid state post-polymerization (post-SSP) was performed on poly(butylene succinate) (PBS) commer... more Solid state post-polymerization (post-SSP) was performed on poly(butylene succinate) (PBS) commercial-and synthesized-grades and monitored for the first time by means of a fluorescent probe: (9-2-carboxy-2-cyanovinyl)julolidine or CCVJ. CCVJ is a molecular rotor and was simply incorporated in the PBS bulk (100 ppm) for fluorescent labelling. Post-SSP runs were then performed following a one-or two-step process. During the one-step process, CCVJ labelled PBS presented a moderate molecular weight (MW) increase (up to 1.15 times) along with a post-crystallization effect. Next, the SSP effectiveness was improved (in terms of MW-up to 4.2 times-and thermal characteristic upgrade) with the addition of a precrystallization step (two-step process). Labelled PBS showed a decrease of the CCVJ fluorescence intensity and a respective significant wavelength shift (blue shift) with SSP time. According to CCVJ calibration, this behavior was ascribed to the resultant MW increment and to the decrease of the acidic index (AI) during SSP. CCVJ was proven a reliable sensor able to act as a molecular rotor as well as a solvatochromic probe sensing both the molecular weight and polarity changes in the course of PBS SSP process.

A new family of crosslinked starch was synthesised in the solid state by UV irradiation without t... more A new family of crosslinked starch was synthesised in the solid state by UV irradiation without the use of any crosslinking agent. The original photosensitiser used was sodium benzoate. Although the final crosslinking density is relatively low, it is still sufficient to render starch nearly insoluble and to modify the "ageing" behaviour. Physical aging (at T<Tg) is only slightly affected by the crosslinking bonds whereas recristallisation (also called retrogradation) is highly modified.

Les differentes etapes pour la preparation de films a base de biopolymeres contenant des biomolec... more Les differentes etapes pour la preparation de films a base de biopolymeres contenant des biomolecules antimicrobiennes et/ou antioxydantes applicables pour la conservation d’aliments perissables sont illustrees par les etudes realisees par 4 equipes de recherche associees a un programme de cooperation Franco-Thailandaise. Ces grandes etapes sont : (i) le choix de la formulation des ingredients entrant dans la composition du film, (ii) les parametres associes aux procedes d’elaboration des films, (iii) la caracterisation des proprietes physico-chimiques des films et l’evaluation in vitro de leur activite antimicrobienne ou antioxydante et (iv) leur application in situ a des aliments perissables pour en evaluer l’effet sur la duree de vie de ces produits. Les biopolymeres filmogenes et les biomolecules actives consideres comprennent des co-produits de l’agriculture Thailandaise comme la gelatine preparee a partir de peau de poisson-chat geant ou un extrait de graines de longane ayant ...

Frontiers in Chemistry, 2019

Cottaz et al. Antimicrobial Model Phenolic for Active Packaging was suitable for a relevant contr... more Cottaz et al. Antimicrobial Model Phenolic for Active Packaging was suitable for a relevant controlled release packaging targeting the preservation of fresh food, but a combination of two of them is promising by the design of a multilayer packaging: the release could result from permeation through an inner PE layer combined with an EVA one acting as a reservoir.

Food Packaging and Shelf Life, 2018

Abstract The capacity of gelatin-based active films to extend the shelf-life of minced pork meat ... more Abstract The capacity of gelatin-based active films to extend the shelf-life of minced pork meat was investigated. In vitro antibacterial and antioxidant activity of films resulted from nisin and catechin incorporation, respectively. Cross-linking of gelatin macromolecules by microbial transglutaminase (MTGase) added in film-forming suspensions resulted in a marked decrease of the films solubility in water. Gelatin films reticulated by MTGase with or without (control) nisin and catechin were thus used to overwrap minced pork meat stored in trays at 5 °C for 7 days. Their gas barrier properties were high enough for the self-development by the respiratory activity of meat microflora of a modified atmosphere with a decreased oxygen and an increased carbon dioxide concentration over 7 days. Interestingly, gelatin films with nisin and catechin retarded lipid oxidation and microbial growth: the time to reach a total viable count of 107 CFU. g−1 of meat was extended from 1 to 4 days.

Carbohydrate Polymers, 2018

In this study, we report a simple, non-degrading and efficient homogeneous acylation of cellulose... more In this study, we report a simple, non-degrading and efficient homogeneous acylation of cellulose diacetate (CDA) by using a large panel of commercially available acylating aliphatic moieties, differing in their structure (fatty, ramified, bulky, cycloaliphatic, aromatic, more or less spaced from the cellulose backbone), in view of generating a library of well-defined cellulose mixed esters with enhanced thermoplasticity. As reflected by a lowering of the glass temperature (Tg), the covalent grafting confers an improved mobility to the cellulose chains, by disrupting the initial H-bonds. In particular, it appears that the gain in free volume is tailored by the substituent structure and that acylating reagents consisting in a terminal bulky moieties spaced from CDA chains by a linear chain efficiently separate macromolecular chains without generating detrimental stiffening interactions (low Tg around 125 °C). Moreover, free-standing films easily prepared by solvent casting exhibit relevant water transport properties, which are closely dictated and tuned by the water solubility of the cellulose mixed ester.

Chemical Engineering Research and Design, 2017

Industrial & Engineering Chemistry Research, 2016

Fossil-based and true bio-based poly(butylene succinate) (PBS) prepolymers were synthesized and s... more Fossil-based and true bio-based poly(butylene succinate) (PBS) prepolymers were synthesized and submitted to solid-state polymerization (SSP) in the proximity of the polyester melting point (Tm), for reaction times up to 29 h under flowing nitrogen. SSP acted as a postcrystallization process, imparting an increase of the PBS melting point up to 126 °C from a starting Tm of 112–114 °C. Adding a precrystallization step prior SSP even resulted in a 2.5 times increase of the initial MW and a Tm shift up to 128 °C. Furthermore, the effect of most critical process parameters on the SSP feasibility and effectiveness was assessed, so as to launch an appropriate operation profile. End-group imbalance turned out to be the most significant key parameter for PBS polymerizability, and various attempts were made toward correcting it. Finally, SSP was examined as a PBS recycling technique and efficiently “revived” hydrolyzed PBS structures.

Trends in Food Science & Technology, 2016