147 research outputs found
Development of nano-encapsulation systems for the food antifungal natamycin: Formulation, characterization and post-processing
No full textFood spoilage has become in the last decades one of the biggest challenges faced by the food industry, with a significant amount of products thrown away at every step of the supply chain. Microbial contamination is listed as one of the major causes of food spoilage and can be at a large extent prevented by application of antimicrobial compounds. Recent trends on the market such as an increasing demand of consumers for natural preservatives and their application in reduced quantities, coupled with the difficulty for industrials to get new antimicrobials approved by health authorities, lead the food industry to a process of reformulation and improvement of functionality and efficiency of already approved ingredients. Natamycin, a naturally-occurring food preservative widely used for the protection of food surfaces, is one of the most popular antifungal agents currently used. This molecule presents several advantages linked to its natural origin, long history of safe use, efficiency at low concentrations and limited modification of food products when applied. Current formulations of the preservative offer however limited specificity or tunability towards applications and little possibilities of controlled/triggered release. This compound also presents a relatively poor aqueous solubility detrimental for its antifungal action and is very sensitive to early-stage degradation by environmental factors such as extreme pH, oxidation and UV exposure. The main goal of this PhD thesis was to determine if the incorporation of this molecule within nano-encapsulation systems could provide benefits for availability, tunability and degradation issues. As a first step, formulation, optimization and characterization of two model nano-encapsulation systems (biodegradable polymeric nanospheres and nano-liposomes) were performed and compared in terms of relative benefit for the encapsulation, delivery, antifungal performance and stability of the antimicrobial. Post-processing of the most promising nano-encapsulation systems in order to obtain commercial products was further evaluated by purification/concentration (tangential flow filtration) or by transformation into redispersible dry products by lyophilization.Nano-liposomes were found overall superior to polymeric nanospheres for the encapsulation and delivery of our molecule and offer higher possible levels of tunability in terms of release rates and antifungal performance. Lyophilization in presence of carbohydrates turned out to be a valuable method for the preparation of dried products with enhanced long-term stability of the antifungal, compared to concentrates prepared by tangential flow filtration, a tedious process that impacted negatively the stability of the preservative
Multiple screening approach for the selection of efficient biological control agents against Botrytis cinerea on tomato
No full textÉvénement(s) lié(s) : - 12. European foundation for plant pathology conference; Malo-les-Bains (FRA) - (2017-05-29 - 2017-06-02)International audienc
THE INFLUENCE OF Β-PBO2 ON PZT PHASE FORMATION
No full textThe reactional mechanism of the formation of solid solution lead-zircono-titanate PZT has been studied using β-PbO2, TiO2 and ZrO2 as starting materials. PZT ceramics were prepared by solid state reaction between oxides at different temperatures. After calcination samples are characterized by thermogravimetry (TGA), differential thermal analysis (DTA), differential scanning, Infrared spectroscopy and x-ray diffraction (XRD). Using lead dioxide (β-PbO2) allows PZT powder to be sintered at a temperature as low as 700°C
THE INFLUENCE OF Β-PBO2 ON PZT PHASE FORMATION
No full textThe reactional mechanism of the formation of solid solution lead-zircono-titanate PZT has been studied using β-PbO2, TiO2 and ZrO2 as starting materials. PZT ceramics were prepared by solid state reaction between oxides at different temperatures. After calcination samples are characterized by thermogravimetry (TGA), differential thermal analysis (DTA), differential scanning, Infrared spectroscopy and x-ray diffraction (XRD). Using lead dioxide (β-PbO2) allows PZT powder to be sintered at a temperature as low as 700°C
(E)-1-[(2,4,6-Tribromophenyl)diazenyl]naphthalen-2-ol
No full textThe title azo molecule, C16H9Br3N2O, adopts a trans conformation with respect to the azo N=N double bond. An intramolecular O—H...N hydrogen bond forms an S(6) ring motif. The dihedral angle between the naphthalene ring system and the benzene ring is 33.80 (16)°. In the crystal, molecules are stacked in columns along the a axis by π–π interactions [centroid–centroid distances = 3.815 (3) and 3.990 (3) Å]
(E)-1-(4-Fluorophenyl)-2-(2-oxidonaphthalen-1-yl)diazen-1-ium
No full textIn the title zwitterion, C16H11FN2O, which belongs to the family of azo dyes, the dihedral angle between the benzene ring and the naphthalene ring system is 15.33 (7)° and an intramolecular N—H...O hydrogen bond closes an S(6) ring. In the crystal, inversion dimers linked by weak C—H...O hydrogen bonds generate R22(16) loops. Aromatic π–π stacking [centroid–centroid distance = 3.585 (11) Å] is also observed
Age and Sex as Risk Factors for Lung Cancer in Setif Region - Algeria: Fuzzy Inference Modeling
No full text1-(3-Acetylphenyl)-2-(2-oxidonaphthalen-1-yl)diazen-1-ium
No full textThe title compound, C18H14N2O2, crystallized with two independent zwitterion molecules (A and B) in the asymmetric unit. They are both close to planar, the dihedral angle between the benzene ring and naphthalene ring system being 4.30 (9)° in A and 4.69 (9)° in B. Each molecule has an E conformation with respect to the azo double bond. In each of the independent molecules, an intramolecular N—H...O hydrogen bond forms an S(6) ring motif. In the crystal, molecules are linked via C—H...O hydrogen bonds, forming –A—A—A– and –B—B—B– chains parallel to one another and propagating along the a-axis direction. There are also π–π interactions between adjacent molecules involving benzene and naphthalene rings [centroid–centroid distance of 3.626 (3) Å for adjacent A molecules and 3.652 (3) Å for adjacent B molecules]
Influence of Bath Temperature, Deposition Time and S/Cd Ratio on the Structure, Surface Morphology, Chemical Composition and Optical Properties of CdS Thin Films Elaborated by Chemical Bath Deposition
No full textChemInform Abstract: Tri‐ and Tetranuclear Palladium‐Cobalt Clusters Containing Bridging Ph2PCH2PPh2(dppm) Ligands. Crystal Structures of (Pd2Co2(μ3‐CO)2(CO)5(μ‐dppm)2) and (Pd2Co(μ3‐CO)2(CO)2(μ‐dppm)2) (PF6).
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