Environmentally friendly films based on chitosan and tetrahydrocurcuminoid derivatives exhibiting antibacterial and antioxidative properties

Environmentally friendly films exhibiting both antibacterial and antioxidative properties were elaborated from chitosan and tetrahydrocurcuminoids (THCs). Two tetrahydrocurcuminoids, THC1 (5-hydroxy-1,7-bis(4- hydroxy-3-methoxyphenyl)hept-4-en-3-one) and THC2 (5-hydroxy-1,7-bis(4-hydroxy-3,5-dimethoxyphenyl)hept-4-en-3-one), were incorporated into a chitosan film. THC1 could be prepared from natural curcumin extracted from turmeric roots (Curcuma longa L.). The resulting tetrahydrocurcuminoid-chitosan films exhibited a high free-radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) in methanol, which was due to a progressive release of the THCs into the solvent. The release kinetics was governed both by molecular interactions between chitosan and THCs and probably by electrostatic forces between the ammonium units in chitosan and the aromatic rings in THCs. These interactions were clearly evidenced by the presence of new absorption bands in the visible regions of the electronic absorption spectra of the THCs. The molecular nature of these interactions was shown using glucosamine, the main monomer of chitosan. When associated with THCs, chitosan retained its bioactivity against Listeria innocua; THCs alone were not bioactive enough against listerial strains

2013b) “Urban goods movement estimation for public decision support: goals, approaches and applications

It is usually considered that urban goods transport proceeds from a complex system (Gonzalez-Feliu and Routhier, 2012). It includes transport system, infrastructures and urban planning, firm’s logistic strategies 1. The main stakes of urban goods movement (UGM) can be considered at different topics and scales: reliability of the different logistic chains, local traffi

Effect of chitosan molecular weight on the antimicrobial activity and release rate of carvacrol-enriched films

Edible films based on three types of chitosan which differ on their molecular weight were developed as carriers of carvacrol. Stable film forming dispersions were obtained and the one developed from chitosan with higher molecular weight presented higher viscosity and larger carvacrol droplets. Olive oil and 96% ethanol were used as food-simulating solvents to determine the carvacrol release rate from the chitosan matrices. The release of carvacrol was much faster when it was submerged in ethanol. Besides, the higher the chitosan molecular weight employed in the films formulation, the faster the release rate towards both solvents. The films showed antimicrobial effectiveness against the gram-negative bacteria Pseudomona fragi, Shewanella putrefaciens and Aeromonas hydrophila, common spoilers of fish and seafood products. Thus, in order to slowdown the carvacrol release rate, the use of chitosan with a low molecular weight and technical applications targeted for low-moderate fat content products is suggested

Comprendre les chaînes de déplacements pour l'approvisionnement des ménages : une approche empirique

National audienceLes déplacements d'achats des ménages représentent plus de la moitié des kilomètres parcourus sur l'ensemble des flux de transport de marchandises dans la ville. Ces déplacements, souvent considérés comme faisant partie des déplacements de personnes, peuvent avoir un intérêt en termes de transport de marchandises, tant pour les collectivités qui réfléchissent à la logistique urbaine comme pour les activités commerciales et les acteurs de la grande distribution dans leurs stratégies commerciales et leurs services de livraison au consommateur. Cet article propose une démarche d'analyse empirique des déplacements d'achats des ménages du point de vue de la logistique urbaine, dans le but d'en modéliser la génération. Nous dressons tout d'abord un panorama des comportements de déplacements d'achats dans les agglomérations françaises. En nous appuyant sur le concept de boucle de déplacements d'achats, nous introduisons les éléments méthodologiques nécessaires à la modélisation des boucles d'achats plutôt que celle des déplacements considérés isolément. Nous montrons ensuite les principaux intérêts de cette approche, et à titre d'exemple nous appliquons le modèle proposé pour estimer les impacts et l'attractivité commerciale des principaux pôles commerciaux de l'aire urbaine lyonnaise. Nous concluons en envisageant des applications possibles de cette méthode pour alimenter une démarche de simulation plus générale, prenant en compte simultanément les chaînes logistiques de distribution (incluant notamment les livraisons à domicile ou en points relais) et les parcours des particuliers réalisant leurs achats

In vitro inhibitory effect of tetrahydrocurcuminoids on Fusarium proliferatum growth and fumonisin B(1) biosynthesis

Many plant pathogens produce toxic metabolites when growing on food and feed. Some antioxidative components seem to prevent fungal growth and mycotoxin formation. Recently, we synthesized a new class of powerful antioxidative compounds, i.e. tetrahydrocurcuminoids, and its structure/antioxidant activity relationships have been established. The South West of France produces large amounts of corn, which can be infected by Fusarium species, particularly F. proliferatum. In this context, the efficiency of tetrahydrocurcuminoids, which can be obtained from natural curcuminoids, was investigated to control invitro the growth of F. proliferatum and the production of its associated mycotoxin, fumonisin B1. The relation between structure and antifungal activity was studied. Tetrahydrocurcumin (THC1), with two guaiacyl phenolic subunits, showed the highest inhibitory activity (measured as radial growth on agar medium) against the F. proliferatum development (67% inhibition at a concentration of 13.6 mu mol ml-1). The efficiencies of THC2 (36% at a concentration of 11.5 mu mol ml-1), which contains syringyl phenolic units, and THC3 (30% at a concentration of 13.6 mu mol ml-1), which does not have any substituent on the aromatic rings, were relatively close. These results indicate that the simultaneous presence of guaiacyl phenols and the enolic function of the -diketone moiety play an important role in the inhibition mechanisms. The importance of this combination was confirmed using n-propylguaiacol and acetylacetone as molecular models. Under the same conditions, ferulic acid and eugenol, other natural phenolic antioxidants, were less efficient in inhibiting fungal growth. THC1 also reduced fumonisin B1 production in liquid medium by approximately 35, 50 and 75% at concentrations of 0.8, 1.3, and 1.9 mu mol ml-1, respectively. These very low inhibitory concentrations show that tetrahydrocurcuminoids could be one of the most promising biobased molecules for the control of mycotoxinogen fungal strains

Impact of UV Irradiation on the Chitosan Bioactivity for Biopesticide Applications

International audienceChitosan is known for its antimicrobial and antifungal properties that make it a promising candidate for plant protection. However, when sprayed in open fields, the bioactivity of chitosan significantly diminishes, suggesting a possible influence of sunlight on chitosan structure. This study aimed to investigate the effects of UV radiation, by using artificial UV sources simulating sunlight, on the stability of chitosan. A powdered chitosan with a low polymerization degree was selected and analyzed using various physicochemical methods, both before and after irradiation. Some minor differences appeared. UV spectra analysis revealed the disappearance of initially present chromophores and the emergence of a new band around 340 nm, potentially indicating the formation of carbonyl compounds. However, elemental analysis, MALDI-TOF spectra, polymerization degree, and infrared spectra did not exhibit any clear structural modifications of chitosan. Interestingly, irradiated powdered chitosan samples maintained their bioactivity, including their eliciting and antifungal properties. In the case of grapevine, irradiated chitosan demonstrated effectiveness in controlling grapevine diseases such as downy mildew, contradicting the assumption that sunlight is responsible for the decreased effectiveness of chitosan in open field conditions

Water transport in cement-in-polymer dispersions at variable temperature studied by magnetic resonance imaging

International audienceResol type resins were prepared in alkaline conditions (potassium hydroxide or potassium carbonate) using furfural obtained by acid hydrolysis of abundant renewable resources from agricultural and foresty waste residues. The structures of the resins were fully determined by 1H, 13C and 2D NMR spectrometries with the help of four models compounds synthesized specially for this stuudy MALDI-Tof mass spectrometry experiments indicated that a majority of linear oligomers and a minority of cyclic ones constituted them. Composites were prepared with furfural-phenol resins and sisal fibers. These fibers were chosen mainly because they came from natural lignocellulosic material and they presented excellent mechanical properties. Thermal analyses (dTG and DSC) and electron microscopy images indicated that the composites displayed excellent adhesion between resin and fibers. Impact strengh measurement showed that mild conditions were more suitable to prepare thermosets. Nevertheless, mild conditions induced a high-diffusion coefficient for water absorption by composites. Composites with good properties could be prepared using high proportion of materials obtained from biomass without formaldehyde

The use of lysozyme to prepare biologically active chitooligomers

Two types of crustacean commercial chitosans (CS1, CS2) were dissolved in lactic acid solutions, hydrolysed by lysozyme and finally fractioned by methanol solutions into two parts containing chito-oligomers (CS-O1, CS-O2). The antioxidant power and antimicrobial properties of both fractions were studied and compared with non-hydrolysed CS1 and CS2. The antioxidant properties were determined by the ferric ion reducing antioxidant power (FRAP) method while the bioactive properties were evaluated against a strain of Listeria monocytogenes. CS-O obtained from the solid fraction of the chito-oligomers solid fractions treated with 90% methanol showed the highest reducing power. Microbiological tests showed that CS-O exhibit higher antilisterial activity than CS

Effect of cross-linking in surface properties and antioxidant activity of gelatin films incorporated with a curcumin derivative

Gelatin was chemically cross-linked with lactose in order to analyze the effect of this reaction in the antioxidant capacity of gelatin films. Since phenolic compounds are formed during cross-linking, the antioxidant activity of gelatin films was assessed. Although these cross-linking films showed certain antioxidant capacity, the incorporation of tetrahydrocurcumin (THC) into the films forming solutions greatly increased the antioxidant capacity of gelatin films. Total phenolic content, expressed as mg gallic acid equivalent (GAE), increased from 14 to 43 mg GAE/L. Furthermore, free radical scavenging capacity showed a three-fold increase, as shown by inhibition values. The changes observed were related to the differences found in the film surface, such as lower gloss and higher roughness