Impact of the crystallisation pathway of inulin on its mono-hydrate to hemi-hydrate thermal transition

In this paper, we present the thermal properties of two inulins obtained from different crystallisation pathways. One was obtained by fractional precipitation of a saturated inulin solution and the second was from the crystallisation of a solid amorphous mulin. The thermal analyses were conducted by temperature resolved wide angle X-ray scattering (TRWAXS), differential scanning calorimetry (DSC) and thermogravimetry (TG). Although at room temperature both inulins presented similar X-ray diffractogram patterns characteristic of the mono-hydrate polymorph, they differed considerably by their thermal properties. During heating, a difference in the mono-hydrate to the hemi-hydrate polymorph transition occurred. Thermogravimetric analysis suggested a difference in the water mobility inside the material which had an impact on the thermal properties and hydrate transition of the crystalline inulin. (C) 2009 Elsevier Ltd. All rights reserved

Determinationofgroundwatermercury(II)contentusingadisposable goldmodified screenprintedcarbonelectrode

Mercury (II)measurementswereperformedthankstoanewlydevelopedelectrochemicalmethodusinga disposablegoldmodified screenprintedcarbonelectrode.Themethodhasawidedynamicrange(1–100 mg/L), agoodaccuracyandalimitofdetectionincompliancewithWHOstandards.Theapplicationofthe methodtoseveralgroundwatersamplesmadeitpossibletoidentify,forthe first time,mercurycontent higherthantherecommendedWHOstandardvalueinagoldminingactivityareainthenorthern partofBurkinaFaso.TheaccuracyoftheassaywascheckedbyICP/MS.info:eu-repo/semantics/publishe

Isolation and identification of inulooligosaccharides resulting from inulin hydrolysis

In this study, inulooligosaccharides (F-n-type inulin) resulting from the endo-inulinase hydrolysis of globe artichoke inulin were purified and characterized. The aim was to produce F-n oligomer standards with the intention of identifying them in the complex inulin chromatogram. Inulin was extracted from globe artichoke and presented a high average degree of polymerization (DP) of about 80 as determined by high-performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). This inulin was hydrolyzed by a commercial endo-inulinase yielding a product with a very high F-n/GF(n), molecule ratio, thus limiting the interference of GF(n) during the purification process. High performance size exclusion chromatography was used to individually isolate and collect each retention peak corresponding to a specific oligomer. The purity of these fractions was checked by HPAEC-PAD and showed that relatively pure molecules were produced. Electrospray ionization mass spectrometry allowed the molecular weight determination of these purified oligomers and ascertained their DP as F-2, F-3 and F-4. These F2-4 standards were used with glucose, fructose, sucrose and GF(2-4) (commercially available) to spike commercial oligofructose products in order to determine the elution profile in the HPAEC-PAD chromatogram

Effect of powder properties on the physicochemical and rheological characteristics of gelation inulin–water systems

peer reviewedThis study investigates the influence of physical properties of powder on the potential functionality of inulin as a polymeric gelator. Inulin powder was characterized using high-performance anion exchange chromatography, wide-angle X-ray, and particle size. Moreover, the inulin–water system was described using rheological properties, optical microscopy, and textural analysis. Four commercial inulins (LC, Instant, Fib97, and HP) were characterized and dissolved in distilled water at three different concentrations (15, 20, and 25%, w/w) at 25 °C. Inulin LC (degree of polymerization, 18.80; semi-crystalline state) and HP (degree of polymerization, 23.74; amorphous state) formed a gel from a concentration of 15% (w/w) and 20%, respectively. Inulin Fib97 (degree of polymerization, 6; amorphous state) and Instant (degree of polymerization, 8; amorphous state) were not able to develop a gel structure. This indicates the significant effect of polymer chain length to form a gel. Textural properties as well as wide-angle X-ray scattering and optical microscopy ascertained a difference in inulin HP– and LC–water system properties. This dissimilarity is related to the different physical properties of powders such as crystallinity and particle size. Indeed, new inulin powders were produced, having the same chemical composition but different physical states (amorphous or crystalline) or particle sizes. The results showed that an amorphous powder with a bigger particle size gave a greater gelation of inulin–water systems. However, beyond a certain size of particles, the systems lose their gelation properties. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature

Impact of the Crystallinity on the Physical Properties of Inulin during Water Sorption

The impact of the crystallinity of spray-dried inulins on their stability and physical properties was investigated after a conditioning of 1 week at different relative humidity levels (0% to 94%) at 20 A degrees C. An environmental scanning electron microscopy study showed that the amorphous powders hardened at a relative humidity storage between 59% and 75%; while their semi-crystalline counterparts were partially agglomerated but friable in the same conditions. Caking was observed when the glass transition temperature of the amorphous phase of the material dropped below the storage temperature of the powder. It resulted in a crystallization of the structural units of varying lengths composing inulin, but also an increase of the crystallinity of the semi-crystalline ones. This study showed the importance of the crystallinity of inulin on its stability and physical properties during storage which is of crucial importance for the shelf-life of food and pharmaceutical products in the dry state

Trace analysis of estrogenic compounds in surface and groundwater by ultra high performance liquid chromatography-tandem mass spectrometry as pyridine-3-sulfonyl derivatives

Natural estrogens (estrone: E1, 17β-estradiol: E2, estriol: E3) and synthetic 17α-ethynylestradiol (EE2) are reported as strong endocrine disruptors even at extremely low concentrations. Therefore, the watch list from the European Commission regarding emerging aquatic pollutants recommended maximum detection limits of 0.035 ng/L for EE2 and 0.4 ng/L for E1 and E2. In this study, a UHPLC-ESI-MS/MS method allowing quantification of E1, E2, E3 and EE2 in aqueous matrices was developed. The analytes were derivatized using pyridine-3-sulfonyl chloride and a broad range of product ions were generated and their specificity was assessed by analyzing both surface and groundwater. At least two product ions for each estrogenic compound were proved to be specific and hence suitable for quantification and confirmation. In complex aqueous matrices, analyte responses were particularly affected by ion suppression. This phenomenon was reduced by optimizing the clean-up and selecting a suitable stationary phase for the chromatographic separation. The limits of quantification assessed in surface water with the optimized method ranged from 0.098 ng/L (EE2) to 2.73 ng/L (E3). © 2017 Elsevier B.V

Characterization of the physical state of spray-dried inulin.

Modulated differential scanning calorimetry, wide angle x-ray scattering, and environmental scanning electron microscopy were used to investigate the physical and morphological properties of chicory root inulin spray dried under different conditions. When the feed temperature increased up to 80 degrees C, the average degree of polymerization of the solubilized fraction increased, leading to a higher glass transition temperature (Tg). Above 80 degrees C, the samples were completely amorphous, and the Tg did not change. The starting material was semicrystalline, and the melting region was composed of a dual endotherm; the first peak subsided as the feed temperature increased up to a temperature of 70 degrees C, whereas above 80 degrees C, no melting peak was observed as the samples were completely amorphous. To a lesser extent, the inlet air temperature of 230 degrees C allowed a higher amorphous content of the samples than at 120-170 degrees C but induced a blow-out of the particles

Engineering of Some Physico-Chemical Properties of Amorphous Spray-Dried Inulin using a Response-Surface Design

The aim of this study was to investigate theeffect of some process variables on the physico-chemicalproperties of amorphous inulin. In this context, athree-factor second-order response-surface model wasfitted to five variables. The factors were feedconcentration and temperature and inlet air temperaturewhile the five variables were bulk and tapped density,particles size, moisture content and the glass transitiontemperature. In the feed concentration (10-40%, w/w),feed temperature (40-90°C) and inlet air temperature(120-230°C) range tested, statistical analysis revealed thatphysico-chemical properties of inulin were mainlygoverned by inlet air temperature and the feedconcentration to a lesser extent. The feed temperature wassecondary in comparison with the two first factors. Inregards to the production parameters, a qualitativemicroscopic study allowed to visualize the morphologicalproperty changes and to correlate them to the physico-chemical properties

Effect of the antibiotic azithromycin on thermotropic behavior of DOPC or DPPC bilayers.

Azithromycin is a macrolide antibiotic known to bind to lipids and to affect endocytosis probably by interacting with lipid membranes [Tyteca, D. Schanck, A. Dufrene, Y.F. Deleu, M. Courtoy, P.J. Tulkens, P.M. Mingeot-Leclercq, M.P. 2003. The macrolide antibiotic azithromycin interacts with lipids and affects membrane organization and fluidity: studies on Langmuir-Blodgett monolayers, liposomes and J774 macrophages. J. Membr. Biol. 192, 203-215]. In this work, we investigate the effect of azithromycin on lipid model membranes made of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Thermal transitions of both lipids in contact with azithromycin are studied by (31)P NMR and DSC on multilamellar vesicles. Concerning the DPPC, azithromycin induces a suppression of the pretransition whereas a phase separation between the DOPC and the antibiotic is observed. For both lipids, the enthalpy associated with the phase transition is strongly decreased with azithromycin. Such effects may be due to an increase of the available space between hydrophobic chains after insertion of azithromycin in lipids. The findings provide a molecular insight of the phase merging of DPPC gel in DOPC fluid matrix induced by azithromycin [Berquand, A. Mingeot-Leclercq, M.P. Dufrene, Y.F. 2004. Real-time imaging of drug-membrane interactions by atomic force microscopy. Biochim. Biophys. Acta 1664, 198-205] and could help to a better understanding of azithromycin-cell interaction.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe