References of "Alsafra, Zouheir"
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See detailOptimization and validation of HS-SPME-GC-MS for the determination of Furan and Alkylfurans in chocolate-based products: Impact of tempering and laser printing
Alsafra, Zouheir ULiege; Scholl, Georges ULiege; Eppe, Gauthier ULiege

in Journal of AOAC International (in press)

Objectives Two major objectives are presented. Firstly, we aim at optimizing and validating a HS-SPME-GC-MS method for the quantification of 5 alkylfurans in chocolate. Secondly, we focus our study on ... [more ▼]

Objectives Two major objectives are presented. Firstly, we aim at optimizing and validating a HS-SPME-GC-MS method for the quantification of 5 alkylfurans in chocolate. Secondly, we focus our study on measuring the quantitative impact of engraving technique on the formation of furan and its derivatives in chocolate, from the raw callets to processed end-products. Method HS-SPME-GC-MS method operating in SIM mode and using isotope dilution technique with deuterated homologue internal standards was used to quantify alkylfurans in chocolate. Results Good repeatability (RSD% = 0.1-8%, in duplicate) and intermediate precision (RSD% = 1.7-7%, n = 6) were obtained for these five process contaminants at 10, 25, and 50 µg/kg. Trueness was varying between 81 and 109%. LoQ ranged from 0.48 to 2.50 µg/kg. Relative expanded measurement uncertainties ranged from 6 to 30%. Finally, tempering is responsible for a 24% increase in furan contamination, while the laser engraving technique results in an additional 31% increase in furan. A similar trend was also observed for 2-methylfuran and 3-methylfuran, whereas no significant increases were observed for 2,3-dimethylfuran and 2,5-dimethylfuran. Conclusions and highlights A reliable and sensitive method of HS-SPME-GC-MS was reported for the first time for the analysis of furan and four alkylfurans in chocolate. This paper demonstrated that engraving using laser-based techniques can increase the levels of these compounds by up to 30%. [less ▲]

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See detailIsolation and Characterization of Two Microalgal Isolates from Vietnam with Potential for Food, Feed, and Biodiesel Production
Luu Thao Nguyen, ULiege; Alsafra, Zouheir ULiege; Corato, Amélie ULiege et al

in Energies (2020), 13

Microalgae are promising feedstock for the production of biodiesel and diverse medium- and high-value products such as pigments and polyunsaturated fatty acids. The importance of strain selection adapted ... [more ▼]

Microalgae are promising feedstock for the production of biodiesel and diverse medium- and high-value products such as pigments and polyunsaturated fatty acids. The importance of strain selection adapted to specific environments is important for economical purposes. We characterize here two microalgal strains, isolated from wastewater of shrimp cultivation ponds in Vietnam. Based on the 18S rDNA-ITS region, one strain belongs to the Eustigmatophyceae class and is identical to the Nannochloropsis salina isolate D12 (JX185299.1), while the other is a Chlorophyceae belonging to the Desmodesmus genus, which possesses a S516 group I intron in its 18S rDNA gene. The N. salina strain is a marine and oleaginous microalga (40% of dry weight (DW) at stationary phase) whole oil is rich in saturated fatty acids (around 45% of C16:0) suitable for biodiesel and contains a few percent of eicosapentaenoic acid (C20:5). The Desmodesmus isolate can assimilate acetate and ammonium and is rich in lutein. Its oil contains around 40%–50% α-linolenic acid (C18:3), an essential fatty acid. Since they tolerate various salinities (10% to 35‰), both strains are thus interesting for biodiesel or aquaculture valorization in coastal and tropical climate where water, nutrient, and salinity availability vary greatly depending on the season. [less ▲]

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See detailISOLATION AND CHARACTERIZATION OF A DESMODESMUS SPECIES FROM VIETNAM WITH POTENTIAL FOR THE PRODUCTION OF ANIMAL FEEDSTOCKS AND NUTRACEUTICALS
Luu Thao Nguyen, ULiege; Remacle, Claire ULiege; Eppe, Gauthier ULiege et al

Poster (2019, December 03)

In this work, a microalgal strain (NL3) was isolated using waste water sampled from shrimp cultivation ponds in the central province of Ninh Thuan, Vietnam. The 18S rDNA-ITS region (3492 bp) was sequenced ... [more ▼]

In this work, a microalgal strain (NL3) was isolated using waste water sampled from shrimp cultivation ponds in the central province of Ninh Thuan, Vietnam. The 18S rDNA-ITS region (3492 bp) was sequenced and used for the phylogenetic identification. As a result, the isolate was identified as Desmodesmus sp. NL3, genus Desmodesmus, family Scenedesmaceae. Desmodesmus sp. NL3 is considered as potential production of biomass with the highest biomass obtained at stationary phase of 1.54 ± 0.06 g L-1. Salinity tolerance experiments (10, 20, 30 and 35‰) were conducted. Desmodesmus sp. NL3 was proved to be highly tolerant to the all the salinities tested. The biomass and protein contents were high and did not vary much among those treatments. FAME analyses of the control and salinity treatments showed that fatty acid chain lengths were of C16 – C18 in which C18:2 and C18:3 were dominant. Therefore, this resulted in the high accumulation of PUFA ranging from 65.80% TFA to 71.53% TFA. Of the four salinity treatments, the highest FAME content of 15.59 %DW was recorded in salinity of 35‰. In terms of pigment, HPLC – DAD was employed for the study and the results reported a high accumulation of lutein which was 4.01, 7.00, 5.67 and 2.24 mg/g DW in 10, 20, 30 and 35‰, respectively. [less ▲]

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See detailChemical composition, kinetic study and antimicrobial activity of essential oils from Cymbopogon schoenanthus L. Spreng extracted by conventional and microwave-assisted techniques using cryogenic grinding
Bellik, Fatima; Benkaci-Ali, Farid; Alsafra, Zouheir ULiege et al

in Industrial Crops and Products (2019)

In this present work, volatile oils from Cymbopogon schoenanthus L. Spreng's (CS) leaves extracted by microwave assisted hydrodistillation (MAHD) and microwave assisted steam distillation (MASD) were ... [more ▼]

In this present work, volatile oils from Cymbopogon schoenanthus L. Spreng's (CS) leaves extracted by microwave assisted hydrodistillation (MAHD) and microwave assisted steam distillation (MASD) were studied according to simple (SG) and cryogenic grinding (CG) and compared with conventional hydrodistillation (HD). Extraction time, kinetics, energy consumption, CO2 rejected, physical properties, chemical composition and antimicrobial activity were investigated for the first time with this specie using microwave extraction and showed that MAD is a promising and innovative technique for extraction of volatile oils; also, cryogenic grinding allowed a high extraction yield compared to the classical grinding (MAHD-CG: 1.76% - MAHD-SG: 1.25%) and (MASD-CG: 1.5% - MASD-SG: 1.11%). GC and GC–MS analysis showed variability in composition according to the technique used especially in major constituents and in chemical classes. Qualitative and quantitative kinetic study demonstrated a significative effect of extraction technique and grinding mode on aromatic profile. Evaluation of antimicrobial activity showed that the efficiency of volatiles from CS varied according to extraction technique used where MASD-SG volatile was the most effective one. [less ▲]

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See detailVolatiles profile of the different parts of Algerian Bupleurum plantagineum Desf. by headspace solid-phase microextraction and hydrodistillation
Mékaoui, Radja; Benkaci-Ali, Farid; Alsafra, Zouheir ULiege et al

in Natural Product Research (2019)

The volatiles from a rare and endemic plant Bupleurum plantagineum Desf collected from Béjaia (Algerian National Park) were analyzed using HS-SPME-GC/MS. The main factors affecting this extraction ... [more ▼]

The volatiles from a rare and endemic plant Bupleurum plantagineum Desf collected from Béjaia (Algerian National Park) were analyzed using HS-SPME-GC/MS. The main factors affecting this extraction technique, including fibre coating, ionic forces (salt adding), temperature and time of extraction were performed in order to reach a maximum of sensitivity. The best results were obtained by PDMS fiber using the powdered leaves at specific temperatures for 25 min, without salt adding. On the other hand, the volatile composition of leaves, stems and roots were determined with a clear prevalence of sesquiterpene hydrocarbons of 45.66, 31.99 and 70.28% respectively. A qualitative comparison with essential oil from hydrodistillation was also performed showing differences essentially in minor components. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. [less ▲]

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See detailA versatile biobased continuous flow strategy for the production of 3-butene-1,2-diol and vinyl ethylene carbonate from erythritol
Tshibalonza Ntumba, Nelly ULiege; Gerardy, Romaric ULiege; Alsafra, Zouheir ULiege et al

in Green Chemistry (2018), 20

A versatile, tunable and robust continuous flow procedure for the deoxydehydration (DODH) of biobased erythritol toward 3-butene-1,2-diol is described. The procedure relies on specific assets of multistep ... [more ▼]

A versatile, tunable and robust continuous flow procedure for the deoxydehydration (DODH) of biobased erythritol toward 3-butene-1,2-diol is described. The procedure relies on specific assets of multistep continuous flow processing. Detailed mechanistic and computational studies on erythritol show that either 3-butene-1,2-diol or butadiene are obtained in high selectivity and yield on demand, as a function of the DODH reagent/substrate ratio and of the process parameters. Short reaction times (1-15 min) at high temperature (225-275 °C) and moderate pressure are reported. 3-Butene-1,2-diol is then further converted downstream into its corresponding carbonate, i.e. 4-vinyl-1,3-dioxolan-2-one (vinyl ethylene carbonate), an important industrial building block. The carbonation step uses a supported organocatalyst, and could be directly concatenated to the first DODH step. This unprecedented procedure also relies on a unique combination of on- and off-line analytical protocols for reaction monitoring and product quantification, and offers a biobased strategy toward important industrial building blocks otherwise petrosourced. [less ▲]

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See detailChemical composition and antioxidant activity of Globularia alypum L. leaves essential oil from Ain-Defla (Algeria)
Amri, H.; Hamadouche, M.; Alsafra, Zouheir ULiege et al

in Chemistry and Chemical Technology (2018), 12(2), 213-220

The chemical composition of essential oil obtained by hydro-distillation with 2.10±0.09 % yield from dried Globularia alypum L. leaves was analyzed by GC-MS. It was determined 60 components representing ... [more ▼]

The chemical composition of essential oil obtained by hydro-distillation with 2.10±0.09 % yield from dried Globularia alypum L. leaves was analyzed by GC-MS. It was determined 60 components representing 99.04 % of total oil. For the evaluation of the mentioned antioxidant activity, three different approaches were performed: the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, β-carotene bleaching (BCB) test systems and ferric reducing/antioxidant power assay (FRAP).The antioxidant was compared with that of synthetic antioxidant ascorbic acid. These findings indicate that the G.alypum essential oil exhibited good antioxidant properties. © Amri H., Hamadouche M., Alsafra Z., Eppe G., El Abed D., 2018. [less ▲]

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See detailDevelopment and optimization of a TD-GC/MS methodology for detection and quantification of furan released in air using of an experimental design.
Alsafra, Zouheir ULiege; Scholl, Georges ULiege; Romain, Anne-Claude ULiege et al

Poster (2016, July 07)

In the aim of understanding the way in which human is exposed to furan present in the air of an occupational area, an analytical method of Thermal desorption-gas chromatography/Mass spectrometry (TD-GC/MS ... [more ▼]

In the aim of understanding the way in which human is exposed to furan present in the air of an occupational area, an analytical method of Thermal desorption-gas chromatography/Mass spectrometry (TD-GC/MS) has been developed and optimized using a Plackett–Burman experimental design. This method was then used to study the phenomena of diffusion of furan released in air from a contamination source. This source of furan is simply a coffee machine located in a closed controlled room. Results show that furan concentration increases quickly over time after turning on the coffee machine until reaching a maxima. Then it starts to decrease slowly. On the other hand, concentration of furan seems to be identical everywhere in the conditioned room in each moment. [less ▲]

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See detailSTUDY OF FURAN FORMATION DURING COFFEE BREWING
Alsafra, Zouheir ULiege; De Pauw, Edwin ULiege; Eppe, Gauthier ULiege et al

Poster (2015, November 05)

Furan (C4H4O) is a small cyclic ether, classified by the International Agency for Research on Cancer (IARC) as possibly carcinogenic to human (group 2B) [1,2]. It has been found in many foodstuffs ... [more ▼]

Furan (C4H4O) is a small cyclic ether, classified by the International Agency for Research on Cancer (IARC) as possibly carcinogenic to human (group 2B) [1,2]. It has been found in many foodstuffs processed by heat treatments [3], where it is formed through multiple pathways, such as Maillard reaction, carbohydrates degradation or lipid oxidation [4,5]. A very popular beverage that is also known as the most contaminated foodstuff by furan is coffee. The high contamination level is known to be related to the bean roasting process occurring at high temperature in anaerobic conditions. Macrae and coworkers in 1985, showed that a small amount of furan precursors remain in coffee even after the roasting and grounding process. The aim of this work is to study the possibility of furan formation in coffee beverages and related cross-products from the remaining traces of precursors within the brewing process conditions. [less ▲]

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See detailThe living of the green microalga Chlamydomonas reinhardtii in day/night cycles
Willamme, Rémi ULiege; Alsafra, Zouheir ULiege; Alsafra, Rameshkumar et al

Poster (2015, March 13)

Detailed reference viewed: 56 (14 ULiège)