Search results for " Chemical Engineering"
showing 10 items of 2965 documents
Effect of ferulic acid and α-tocopherol antioxidants on properties of sodium caseinate edible films
2011
Edible films, based on sodium caseinate containing three different concentrations of ferulic acid or alpha-tocopherol (20, 40 and 60 mg/g sodium caseinate), were obtained in order to evaluate the effect of these compounds on properties of the caseinate matrices. Special emphasis was placed on their effect on the films' oxygen barrier properties, which are decisive in the prevention of the oxidation of foods containing lipids. Films were characterized as to their tensile, optical and surface properties as well as their barrier properties to water vapor, oxygen and aroma compounds (n-hexanal and n-hexanol). Ferulic acid was more efficient at reducing oxygen and n-hexanal permeability than alp…
Synthesis and studies of calcium channel blocking and antioxidant activities of novel 4-pyridinium and/or N-propargyl substituted 1,4-dihydropyridine…
2014
The novel 1,4-dihydropyridine derivatives containing the cationic pyridine moiety at the position 4, and the N-propargyl group as a substituent at position 1 of the 1,4-DHP cycle were designed, synthesised, and assessed in biological tests. Among all the novel compounds, the 4-(N-dodecyl) pyridinium group-containing compounds 11 (without the N-propargyl group) and 12 (with the N-propargyl group) demonstrated the highest calcium antagonistic properties against neuroblastoma SH-SY5Y (IC50 about 5–14 mM) and the vascular smooth muscle A7r5 cell (IC50 – 0.6–0.7 mM) lines, indicating that they predominantly target the L-type calcium channels. These compounds showed a slight total antioxidant act…
Alteration of the Mitochondrial Effects of Ceria Nanoparticles by Gold: An Approach for the Mitochondrial Modulation of Cells Based on Nanomedicine
2020
Ceria nanoparticles are cell compatible antioxidants whose activity can be enhanced by gold deposition and by surface functionalization with positive triphenylphosphonium units to selectively target the mitochondria. The antioxidant properties of these nanoparticles can serve as the basis of a new strategy for the treatment of several disorders exhibiting oxidative stress, such as cancer, diabetes or Alzheimer&rsquo
High Throughput Screening for Bioactive Volatile Compounds and Polyphenols from Almond (Prunus amygdalus) Gum: Assessment of Their Antioxidant and An…
2016
This work was devoted to recover and identify bioactive polyphenols and volatile compounds from almond gum, which can be used as food additives and/or nutraceuticals. For this purpose, solvent extract was obtained after hydrodistillation of almond gum and the extracted volatiles were identified using gas chromatography-mass spectrometry (GC-MS). The major compounds were 9-octadecenoic acid (18.47%), 3-eicosene (17.04%), hexadecanoic acid (13.82%), benzyl salycilate (9.54%), 1-octadecene (7.28%), cetene (4.38%) and turmerone (3.2%). Subsequently, the antioxidant and antibacterial activities of the obtained extracts rich in polyphenols and volatile compounds were evaluated. Antioxidant activi…
Stability and bioaccessibility of EGCG within edible micro-hydrogels. Chitosan vs. gelatin, a comparative study
2016
Micro-hydrogels are very promising systems for the protection and controlled delivery of sensitive bioactives, but limited knowledge exists regarding the impact of this encapsulation on their bioaccessibility. In this work, two different hydrogel-forming biopolymers (gelatin and chitosan) were compared as wall materials for the microencapsulation of a model flavonoid, (−)-epigallocatechin gallate (EGCG). Results showed that gelatin was more adequate as wall material for the encapsulation of EGCG than chitosan, achieving higher encapsulation efficiencies (95% ± 6%), being more effective in delaying EGCG release and degradation in aqueous solution and exhibiting a 7 times higher bioaccessibil…
Sustainable bioactive pectin-based films to improve fruit safety via a circular economy approach.
2023
This work reports on the valorisation of persimmon (Diospyros kaki Thunb.) for the development of food-grade antiviral coatings against major viral foodborne pathogens, human noroviruses (NoVs) and hepatitis A virus (HAV). Initially, the antiviral activity of polyphenol-rich pectin extracts with abundant non-covalent interactions (PPN), pectin extracts enriched with intact pectin-polyphenol ester and O-glycosyl bonds (PPC) and hydro-ethanolic polyphenol-rich extracts (EPE) was compared. Higher viral reductions were found for the pectin extracts rich in polyphenols, mainly in those containing covalent pectin-polyphenol interactions. This specific extract was mixed with commercial citrus pect…
A Tool for Predicting the Dynamic Response of Biotrickling Filters for VOC Removal
2016
This article presents the development of a MATLAB® computer program to simulate the performance of biotrickling filters. Since these filters behave differently during spraying and nonspraying cycles, the presented simulation tool is built on top of a mathematical description of each situation. The resulting variable-structure model is then used as the basis for simulation experiments. The model presented herein represents the first attempt to take into account the variable spraying pattern usually found in industrial installations. Overall, the software is flexible and easy to use, allowing the user to specify the emission concentration pattern, the gas concentration pattern, as well as the…
Interaction between nitroxyl radicals and CdTe quantum dots: Determination of fluorescence-quenching mechanisms in aqueous solution
2019
Abstract The present work characterizes the optical properties of CdTe quantum dots (CdTe QDs) after interaction with nitroxyl radicals based on steady-state and time-resolved fluorescence spectroscopy studies. QDs of different sizes were exposed to 2 different nitroxyl radicals, i.e., TEMPO and 4-amino-TEMPO radicals. A clear dependence of dynamic and static Stern-Volmer constants values, KD and KS, respectively, was observed as a function of the size of QDs used, with a change from a mostly static mechanism (for smaller QD sizes) to a dynamic mechanism predominating as the nanoparticles increase in size. All observed effects are dependent on both the concentration of the radical and the s…
Conversion electron Mössbauer study of low carbon steel polarized in aqueous sulfate and sulfite containing sulfate solutions
1993
Abstract The passivation of low carbon steel was studied in aqueous solutions of 0.5 M Na 2 SO 4 (pH = 3.5 and 6.5) and of 0.5 M Na 2 SO 4 + 0.001 M NaHSO 3 (pH 3.5 and 6.5). The used conversion electron Mossbauer spectroscopy (CEMS) with the complementary electrochemical, microscopic and spectrophotometric investigations proved that the presence of sulfite ion induces pitting corrosion. The compositions and thichnesses of the passive films formed during the electrochemical treatments are determined from the conversion electron Mossbauer spectra. γ-FeOOH was found in each case as a major component. At pH = 3.5, the sextet belonging to Fe 3 C appears in the spectra in most cases, and also Fe…
Analysis of an impedance function of zinc anodic dissolution
2004
Zinc anodic dissolution has been studied by means of electrochemical impedance spectroscopy (EIS). The kinetic study of the oxidation mechanism has allowed us to propose a theoretical impedance function for this system in deaerated sulphate medium. Relevant information on the faradaic process is provided by analysis of the theoretical impedance function. Kinetic parameters of this system can be calculated from the fitting of experimental data to the faradaic impedance function deduced theoretically. The physical measurements of this function are analysed by means of the dependence of simulated EIS spectra on kinetic parameters.