References of "Attia, Hamadi"
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See detailImpact of extraction procedures on the chemical, rheological and textural properties of ulvan from Ulva lactuca of Tunisia coast
Yaich, Hela; Garna, Haikel; Besbes, Souhail et al

in Food Hydrocolloids (2014), (40), 53-63

The impact of the extraction conditions has been studied on the yield, chemical composition, rheological and textural properties of ulvan from the green seaweed Ulva lactuca. High ulvan yield was obtained ... [more ▼]

The impact of the extraction conditions has been studied on the yield, chemical composition, rheological and textural properties of ulvan from the green seaweed Ulva lactuca. High ulvan yield was obtained after combining enzymatic and chemical extraction but the lowest yield results at the drastic conditions (pH 1.5 and 90 C). Besides, solvent acidity was an important parameter controlling the ulvan extraction efficiency. The different extraction processes affected chemical composition of ulvan extracts and in particular, sulphate, ash and sugar contents. Low proportions of galactose, glucose and protein were also found in sulphated polysaccharides. The extract, which is resulted from combined enzymatic and chemical extraction, was mainly composed of high peak molecular weight polysaccharides. Ulvan hy-drocolloids demonstrated a pseudoplastic behavior. Viscoelastic behavior was carried out at a concen-tration of 1.6% (w/v) in the presence of 7 mM sodium tetraborate and at pH 7.5. However, polysaccharides formed a gel. It was not the case for the extract at pH 1.5 and 90 C under the same conditions. The results showed that a significant effect of the conditions of extraction on the textural characteristic (firmness, springiness and adhesiveness) of ulvan gels. [less ▲]

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See detailOsmotic dehydration of pomegranate seeds (PUNICA GRANATUM L.)
Bchir, Brahim ULg; Besbes, Souhail; Attia, Hamadi et al

Poster (2013, May 30)

Osmotic dehydration of pomegranate seeds was carried out at different temperatures (30, 40, 50°C) in a 55°Brix solution of sucrose, glucose, and mixture sucrose & glucose (50:50 wt/wt). The most ... [more ▼]

Osmotic dehydration of pomegranate seeds was carried out at different temperatures (30, 40, 50°C) in a 55°Brix solution of sucrose, glucose, and mixture sucrose & glucose (50:50 wt/wt). The most significant changes of water loss and solids gain took place during the first 20 min of dewatering. During this period, seeds water loss was estimated to 46% in sucrose, 37% in glucose and 41% in mix glucose/sucrose solution. The increase of temperature favoured the increase of water loss, weight reduction, solids gain and effective diffusivity. Differential scanning calorimetry data provided complementary information on the mobility changes of water and solute in osmodehydrated pomegranate seeds. The ratio between % frozen water and % unfreezable water decreased from 5 to 0.5 during the process. That involving the presence of very tightly bound water to the sample, which is very difficult to eliminate with this process. It also appeared that glass transition temperature depends on the types of sugar. [less ▲]

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See detailEffect of extraction conditions on the yied and purity of ulvan extracted from Ulva lactuca
Yaich, Hela; Garna, Haikel; Besbes, Souhail et al

in Food Hydrocolloids (2013)

A study of the influence of extraction conditions (pH: 1.5 and 2; temperature: 80 °C and 90 °C; extraction time: 1-3 h), on the yield, chemical composition and purity of the sulphated cell wall ... [more ▼]

A study of the influence of extraction conditions (pH: 1.5 and 2; temperature: 80 °C and 90 °C; extraction time: 1-3 h), on the yield, chemical composition and purity of the sulphated cell wall polysaccharides ulvan, extracted from the green seaweed Ulva lactuca and precipitated by alcohol is carried out. The alcohol precipitate yields varied from 21.68% to 32.67% (%dw/dw) depending on the pH. At pH 2, the alcohol precipitate yields and the uronic acid recovery from extract juice are higher than those obtained at pH 1.5. Other compounds than ulvan such as cellulose, hemicellulose, proteins and ash are solubilized from the cell walls of Ulva lactuca at both pH, and they are precipitated with alcohol. The alcohol precipitate obtained from different extraction conditions has high uronic acid (20.37%-23.60%) and neutral sugar content (20.09%-29.12%), especially when the conditions (pH, temperature) are drastic. It contains rhamnose (13.35%-15.59%), glucose (2.90%-10.97%), and xylose (2.36%-2.73%). A decrease in the molecular weight of ulvan was observed at acid pH, and for long extraction times. The presence of proteins (1.94%-2.32%) and inorganic material (33.36%-47.15%) in alcohol precipitate prove the lower purity of ulvan extracted and shows that ulvan precipitation with ethanol is not specific. © 2012 Elsevier Ltd. [less ▲]

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See detailEffect of concentration temperature on some bioactive compounds and antioxidant proprieties of date syrup
Abbès, Fatma; Besbes, Souhail; Bchir, Brahim ULg et al

in Food Science & Technology International (2013), 19

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See detailEffect of air-drying conditions on physical and nutritional properties of osmotically pre-treated pomegranate seeds
Bchir, Brahim ULg; Besbes, Souhail; Karoui, Romdhane et al

Poster (2012, June 01)

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See detailEFFECT OF DATE FLESH FIBER CONCENTRATE ADDITION ON DOUGH PERFORMANCE AND BREAD QUALITY
Borchani,, Chema; Masmoudi, Manel; Besbes, Souhail et al

in JOURNAL OF TEXTURE STUDIES (2011), 42(4), 300-308

Date flesh fiber concentrate (DFFC) of Deglet Nour variety were extracted and incorporated in a bakery product. Dough rheological characteristics showed that water absorption, stability, index quality ... [more ▼]

Date flesh fiber concentrate (DFFC) of Deglet Nour variety were extracted and incorporated in a bakery product. Dough rheological characteristics showed that water absorption, stability, index quality, resistance to deformation increased with the amount of added fiber, whereas degree of softening and extensibility decreased in all levels of fiber. Bread evaluation revealed that DFFC addition caused an increase of bread yield especially for the highest levels, a change of crumb color and an insignificant decrease of bread volume. Breads are subjected to sensory evaluation for odor, taste, crumb color, crumb smoothness and overall acceptability. Significant differences were not found (P > 0.05) between scores for all sensory parameters. [less ▲]

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See detailDate syrup: Effect of hydrolytic enzymes (pectinase/cellulase) on physico-chemical characteristics, sensory and functional properties
Abbes, Fatma; Bouaziz, Mohamed Ali; Blecker, Christophe ULg et al

in Lwt-Food Science And Technology (2011), 44(8), 1827-1834

This work is a contribution to give value addition to second grade dates (with hard texture) by the production of enzymatically treated syrup with high commercial value. It was observed that the pulp ... [more ▼]

This work is a contribution to give value addition to second grade dates (with hard texture) by the production of enzymatically treated syrup with high commercial value. It was observed that the pulp:water at ratio 1:3 treated with 50 U of pectinase and 5 U of cellulase during 120 min at 50 degrees C gave the highest recovery of total soluble solids (72.37 g of total soluble solids/100 g fresh basis) and the lower turbidity (186.45 NTU) compared with control without enzyme addition (Total soluble solids yields: 66.34 g of total soluble solids/100 g fresh basis and turbidity: 1513 NTU). physico-chemical measurements indicated that carbohydrates were predominant in all date varieties as well as their syrups (similar to 69.59-83.76 g/100 g dry matter in dates and similar to 62.14-74.68 g/100 g fresh weight in syrup). Allig variety was characterised by a high content of reducing sugars content (similar to 77.91 g/100 g dry matter), contrary to Deglet Nour (similar to 23.17 g/100 g dry matter) and Kentichi (similar to 21.3 g/100 g dry matter). The CIE L* a* b* colour values of the enzyme-treated date syrup of Deglet Nour, Allig and Kentichi variety showed lighter colours (L* values ranging from 24.16 to 44) than the control without enzyme (L* values ranging from 0.545 to 17.2). Hedonic evaluation showed that enzyme-treated date syrup was more appreciated by consumers. Microbiological study showed that date syrups were free from aerobes, moulds, coliforms and enterobacteriaceae and were microbiologically stable during five months storage. Results suggested that enzymatic treatment could be used for production of date syrup with high commercial value (C) 2011 Elsevier Ltd. All rights reserved. [less ▲]

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See detailSynthèse des connaissances sur la déshydratation osmotique
Bchir, Brahim ULg; Besbes, Souhail; Giet, Jean-Michel ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment (2011), 15(1), 129-142

Among the preservation processes of vegetal products, osmotic <br />dehydration presents an economic and a nutritional interest. This technique consumes a low quantity of energy, prolongs the <br />period ... [more ▼]

Among the preservation processes of vegetal products, osmotic <br />dehydration presents an economic and a nutritional interest. This technique consumes a low quantity of energy, prolongs the <br />period of availability of foodstuffs, and gives new and appreciated sensory properties to products. Therefore, the producers <br />can sell their productions at better prices and the consumers are able to consume fruits and vegetables throughout the year. <br />This technique is very easy to set up, especially in the developing countries due to its low cost. The aim of this article is to <br />present a synthesis of the literature concerning the osmotic dehydration technique, and also to specify the new tendencies and <br />directions of recent research. [less ▲]

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See detailDietary fibre and fibre-rich by-products of food processing characterisation, technological functionality and commercial applications: a review
Elleuch, mohamed; Bedigian, Dorothy; Roiseux, Olivier et al

in Food Chemistry (2011), 124

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See detailEffect of Air-Drying Conditions on Physico-chemical Properties of Osmotically Pre-treated Pomegranate Seeds
Bchir, Brahim ULg; Besbes, Souhail; Karoui, Romdhane et al

in Food and Bioprocess Technology (2010)

The drying of pomegranate seeds was investigated <br />at 40 °C, 50 °C and 60 °C with air velocity of 2 m/s. <br />Prior to drying, seeds were osmodehydrated in 55 °Brix <br />sucrose solution for 20 min ... [more ▼]

The drying of pomegranate seeds was investigated <br />at 40 °C, 50 °C and 60 °C with air velocity of 2 m/s. <br />Prior to drying, seeds were osmodehydrated in 55 °Brix <br />sucrose solution for 20 min at 50 °C. The drying kinetics <br />and the effects of osmotic dehydration (OD) and air-drying <br />temperature on antioxidant capacity, total phenolics, colour <br />and texture were determined. Analysis of variance revealed <br />that OD and air-drying temperature have a significant <br />influence on the quality of seeds. Both anthocyanin and <br />total phenolic contents decreased when air-drying temperature <br />increased. The radical diphenylpicril-hydrazyl activity <br />showed the lowest antioxidant activity at 60 °C. Both <br />chromatic parameters (L*, C* and h°) and browning index <br />were affected by drying temperatures, which contributed to <br />the discolouring of seeds. The final product has 22%, 20% <br />and 16% of moisture; 0.630, 0.478 and 0.414 of aw; 151, <br />141 and 134 mg gallic acid equivalent/100 g fresh matter <br />(FM) of total phenolics; 40, 24, 20 mg/100 g FM of <br />anthocyanins and 46%, 39% and 31% of antioxidant <br />activity, for drying temperatures of 40 °C, 50 °C and <br />60 °C, respectively. In view of these results, the temperature <br />of 40 °C is recommended as it has the lowest impact on <br />the quality parameters of the seeds. Differential scanning <br />calorimetry data provided complementary information on <br />the mobility changes of water during drying. Glass <br />transition temperature (Tg′) depends on moisture content <br />and as consequence, on drying conditions. In fact, Tg′ of <br />seeds dried at 60 °C (Tg′=−21 °C) was higher than those <br />dried at 50 °C (Tg′=−28 °C) or 40 °C (Tg′=−31 °C) and <br />osmodehydrated seeds (Tg′=−34 °C). During OD and <br />drying process, the texture of seeds changed. The thickness <br />of seeds shrank by 55% at 60 °C. [less ▲]

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See detailUtilisation du jus de datte comme milieu d’immersion pour la déshydratation osmotique des graines de grenade
Bchir, Brahim ULg; Besbes, Souhail; Karoui, Romdhane et al

Poster (2010, October 14)

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See detailChemical characteristics and oxidative stability of sesame paste, and olive oils.
Borchani, C.; Besbes, Souhail; Blecker, Christophe ULg et al

in Journal of Agricultural Science and Technology (2010), 12

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See detailOsmotic Dehydration Kinetics of Pomegranate Seeds Using Date Juice as an Immersion Solution Base
Bchir, Brahim ULg; Besbes, Souhail; Karoui, Romdhane et al

in Food and Bioprocess Technology (2010)

Pomegranate seeds were osmodehydrated using date juice added with sucrose (final °Brix, 55) as immersion solution. The kinetics of osmotic dehydration showed that the most significant changes of mass ... [more ▼]

Pomegranate seeds were osmodehydrated using date juice added with sucrose (final °Brix, 55) as immersion solution. The kinetics of osmotic dehydration showed that the most significant changes of mass transfer took place during the first 20 min of the process, regardless of date juice <br />varieties. During this time, seed water loss and solid gain were estimated to be ∼39% and ∼6%, respectively. After 20 min of the process, the percentage of water loss and solid gain varied slightly and ranged on average close to ∼40% and ∼9%, respectively. During osmotic dehydration, there was a leaching <br />of natural solutes from seeds into the solution, which is <br />quantitatively not negligible, and might have an important <br />impact on the sensorial and nutritional value of seeds and date <br />juices. Both scanning electron microscopy and texture <br />(compression) analysis revealed that osmotic dehydration <br />process induced modifications of seed texture and cell <br />structure. Sucrose was found to be the essential element which <br />influences the texture of seed and the viscosity of date juice. <br />Additionally, natural sugar present in date juice permits <br />substituting 35% of the total quantity of sucrose added to the <br />osmotic solution. [less ▲]

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See detailChemical properties of 11 date cultivars and their corresponding fibers extracts.
Borchani, C.; Besbes, Souhail; Blecker, Christophe ULg et al

in African Journal of Biotechnology (2010), 9(26), 4096-4105

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See detailCharacterisation of proteins from date palm sap (Phoenix dactylifera L.) by a proteomic approach
Ben Thabet, Imène; Francis, Frédéric; De Pauw, Edwin et al

in Food Chemistry (2010)

The proteins contained in juice tapped from date palm (Phoenix dactylifera L.), from Deglet Nour variety, were analysed by the application of two-dimensional electrophoresis (2DE). Identification was ... [more ▼]

The proteins contained in juice tapped from date palm (Phoenix dactylifera L.), from Deglet Nour variety, were analysed by the application of two-dimensional electrophoresis (2DE). Identification was carried out by mass spectrometry analyses. The SDS–PAGE patterns showed more than 100 spots of which 52 spots were identified. A proportion of the identified proteins were related to Saccharomyces cerevisiae that may belong to the natural microflora of date palm sap. These proteins are principally involved in glycolysis. While other proteins were assigned to be vegetable proteins, probably a mixture of proteins from the vascular system, which have several biological functions within the palm tree. Thus, we found enzymes involved in stress and defence reactions, in glycolysis, and photosynthesis reactions. Other enzymes are associated with carbohydrates and proteins metabolisms. [less ▲]

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See detailEffect of the addition of deffated date seeds on wheat dough performance and bread quality.
Bouaziz, M. A.; Besbes, Souhail; Blecker, Christophe ULg et al

in Journal of Texture Studies (2010), 41

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See detailPectin extraction from lemon by-product with acidified date juice : effect of extraction conditions on chemical composition of pectin.
Masmoudi, M.; Besbes, Souhail; Chaabouni, M. et al

in Food Science & Technology International (2010), 16(2), 105-114

The microstructure and the rheological properties of lemon-pectin mixtures were studied and compared to those of pure lemon (high methoxyl: HM) and date (low methoxyl: LM) pectins. Rheological properties ... [more ▼]

The microstructure and the rheological properties of lemon-pectin mixtures were studied and compared to those of pure lemon (high methoxyl: HM) and date (low methoxyl: LM) pectins. Rheological properties were carried out in the presence of 30%, 45% and 60% sucrose, and increasing calcium concentrations (0-0.1%). The presence of date with lemon pectin led to a gel formation at 45% sucrose and in the presence of calcium, which was not the case for lemon pectin alone under the same conditions. It is suggested that lemon and date pectins interacted, leading to gel formations at different gelling temperatures, which were strongly dependant on degree of methylation. These results were confirmed by scanning electron microscopy, which revealed inhomogeneous gels where dense aggregated network and loose, open network areas were present. Addition of calcium to pectin mixture gels led to stronger and faster gel formation. [less ▲]

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See detailOSMOTIC DEHYDRATION OF POMEGRANATE SEEDS (PUNICA GRANATUM L.): EFFECT OF FREEZING PRE-TREATMENT
Bchir, Brahim ULg; Souhail, Besbes; Attia, Hamadi et al

in Journal of Food Process Engineering (2010)

The osmotic dehydration of pomegranate seeds was compared using fresh and frozen seeds. The process was carried out at 50C in a 55°Brix solution of sucrose. Freezing pomegranate seeds before osmotic ... [more ▼]

The osmotic dehydration of pomegranate seeds was compared using fresh and frozen seeds. The process was carried out at 50C in a 55°Brix solution of sucrose. Freezing pomegranate seeds before osmotic dehydration involved an increase of effective diffusivity and a reduction in dehydration time. The most significant changes of water loss (WL) (46 g/100 g of fresh seeds [FS]) and solids gain (SG) (7 g/100 g of FS) took place during the first 20 min for frozen seeds. After this period, seeds WL and SG ranged on average close to 43 and 8 g/100 g of FS, respectively. Osmotic dehydration was slower starting from fresh fruits but led to a higher rate of WL (62 g/100 g of FS) at the end of the process. Both scanning electron microscopy and texture analysis showed a destruction of cell structure and seed texture during the pretreatment (freezing). The same techniques also revealed a texture/structure modification induced by the osmotic dehydration process [less ▲]

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See detailDate Fiber Concentrate: Chemical Compositions, Functional Properties and Effect on Quality Characteristics of Beef Burgers
Besbes, Souhail; Ghorbel, Raoudha; Ben Salah, Riadh et al

in Journal Of Food And Drug Analysis (2010), 18(1), 8-14

Chemical composition of second-grade dates (with hard texture) from Tunisian Deglet Nour cultivar was similar to that of commercial dates. Date fiber concentrate (DFC) was extracted and characterized in ... [more ▼]

Chemical composition of second-grade dates (with hard texture) from Tunisian Deglet Nour cultivar was similar to that of commercial dates. Date fiber concentrate (DFC) was extracted and characterized in terms of chemical composition and techno-functional properties. DFC showed interesting functional properties. In fact, it presented high water binding capacities (WBC) and oil binding capacities (OBC) reaching 15.82 g/g and 11.31 g/g, respectively. These Values were higher than those reported for the most fruits and vegetable fiber concentrates. The use of DFC in beef burger formulations improves cooking properties, e.g. increase cooking yield and decrease shrinkage and minimize production Cost Without negatively affecting their sensory properties. Results indicate the potentially functional and economic utility Of Phoenix L. Flesh from dry dates as new source of dietary fiber. [less ▲]

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