References of "Bchir, Brahim"
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See detailComparative study of alkaline extraction process of hemicelluloses from pear pomace
Rabetafika, Holy-Nadia ULg; Bchir, Brahim ULg; Blecker, Christophe ULg et al

in Biomass & Bioenergy (2014), 61

Hemicelluloses were produced from pear pomace using direct alkaline extraction (sodium hydroxide and hydrogen peroxide) and two-step extraction with delignification pre-treatment (acidified sodium ... [more ▼]

Hemicelluloses were produced from pear pomace using direct alkaline extraction (sodium hydroxide and hydrogen peroxide) and two-step extraction with delignification pre-treatment (acidified sodium chlorite/sodium hydroxide). The aim of the study was to compare the extraction yield, composition and physicochemical characteristics of isolated hemicelluloses by size exclusion chromatography, FTIR and thermogravimetric analyses. Solid residues were analysed in order to evaluate the effect of processes on co-products (lignins and cellulose). Delignification of material (up to 995.4 g kg−1 of original lignins) during the direct alkaline hydrogen peroxide and two-step acidified sodium chlorite/sodium hydroxide processes improved the hemicellulose extraction yield attaining up to 945.3 g kg−1. Hemicelluloses were mainly composed of xylans (xylose/glucose ratio of 4.6–16.2) and had low lignin content (53.5–61.0 g kg−1 dry matter). Those from direct sodium hydroxide extraction were composed of xylans and glucans (xylose/glucose ratio of 1.5) with high content of lignins (149.3 g kg−1 dry matter). All isolated fractions were a mixture of polymers and oligomers with a molecular mass ranging from 1710 g mol−1 to 8 870 000 g mol−1. The two-step process gave the most pure cellulose residue (799.2 g kg−1 dry matter). According to results, the direct alkaline extraction with hydrogen peroxide was a promising process for the production of pure xylose-rich hemicelluloses from pear pomace solubilizing 802.2 g kg−1 of the original hemicelluloses but induced fragmentation of hemicelluloses. [less ▲]

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See detailEncres anciennes: utilisation non conventionnelle d'aliments
Bouchat, Isabelle; Wymeersch, Noémie; Bchir, Brahim ULg et al

in Septième symposium du GCNAS: Vendredi 6 décembre, Louvain-La-Neuve (2013, December 06)

De tout temps l’homme utilise des pigments pour peindre. Il y a 27.000 ans déjà, près de Marseille, dans la grotte Cosquer, des fresques furent peintes par des hommes préhistoriques. Il existe deux ... [more ▼]

De tout temps l’homme utilise des pigments pour peindre. Il y a 27.000 ans déjà, près de Marseille, dans la grotte Cosquer, des fresques furent peintes par des hommes préhistoriques. Il existe deux grandes catégories de pigments et colorants: les naturels et les artificiels. La première catégories contient les pigments minéraux tels que les argiles (ocre jaune ou rouge, argile verte ou brune) mais aussi des pierres (lapis lazuli (bleu)) et les pigments organiques d’origine végétale (gaude (jaune)) ou d’origine animale (murex (pourpre). La deuxième catégorie contient les pigments et colorants artificiels issus de réactions chimiques (minium (orange)) ou bien des mi-végétaux, mi-minéraux comme les encres ferro-galliques classés dans les divers. Après avoir servi pendant plusieurs siècles, tous ces pigments ont été remplacés à la fin du XIXe par des colorants synthétiques issus de la pétrochimie, car ces derniers ont l'avantage de la reproductibilité constante des couleurs. Mais la fin programmée du pétrole suscite un regain d'intérêt pour les préparations naturelles. C'est donc très logiquement que notre laboratoire a décidé de s'intéresser au sujet et en particulier aux encres venant du jus de chou rouge et aux encres ferro-grenadiques en collaboration avec l'Abbaye de Villers-la-Ville. [less ▲]

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See detailEffect of Pear, Apple and Date Fibres from Cooked Fruit By-products on Dough Performance and Bread Quality
Bchir, Brahim ULg; Rabetafika, Holy-Nadia ULg; Paquot, Michel ULg et al

in Food and Bioprocess Technology (2013)

Abstract This study examined the effect of the incorporation of flesh fibre concentrate (FFC) from apple, pear, and date pomaces on wheat bread dough performance and bread quality. The nutritional ... [more ▼]

Abstract This study examined the effect of the incorporation of flesh fibre concentrate (FFC) from apple, pear, and date pomaces on wheat bread dough performance and bread quality. The nutritional composition and techno-functional properties (water-holding capacity, oil-holding capacity, swelling capacity) of FFC were determined beforehand. Dough performance was evaluated by farinograph, alveograph and visco-amylograph. Bread quality was assessed by physical (weight, specific volume, and color) and textural (hardness and elasticity) parameters. Digital imaging analysis was also performed in order to better understand the observed effects. Results showed that the addition of FFC in wheat flour significantly improved (P<0.05) dough properties inducing an increase of water absorption (from 55 to 60 %), of stability (from 4 to 31 min),of tenacity (from 83 to 116 mmH2O) , a reduction of extensibility (from 69 to 29 mm), of softening (from 60 to 20 BU), of breakdown (from 34 to 25 BU) and of setback (from 103 to 93 BU) in comparison to the control dough (without fibre). The formulation containing FFC produced loaves that had various colors (crust, 0<ΔE*<10 and crumb, 0<ΔE*<20;ΔE* corresponding to color variation), a comparable specific volume (2.7 vs 2.9 cm3/g for control) and a more aerated internal crumb structure compared to the control. During storage of breads at 20 °C, there was no significant difference [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 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 detailEffects of Processing on the Compositions and Physicochemical Properties of Fibre Concentrate from Cooked Fruit Pomaces
Rabetafika, Holy-Nadia ULg; Bchir, Brahim ULg; Aguedo, Mario ULg et al

in Food and Bioprocess Technology (2013)

This study examined the influence of applied tech- nologies namely desugaring, grinding, and bleaching on the compositions (cellulose, hemicelluloses, lignins, and pectins), physicochemical properties ... [more ▼]

This study examined the influence of applied tech- nologies namely desugaring, grinding, and bleaching on the compositions (cellulose, hemicelluloses, lignins, and pectins), physicochemical properties (water-holding capacity (WHC), swelling capacity (SWC), oil-holding capacity (OHC)) and the colour of dietary fibre (DF) during the production of fibre concentrates from unusual cooked apple and pear pomaces. Thermogravimetric analysis (TGA) and optical microscopy were also performed to monitor process-induced modifica- tion. All the processing conditions affected the compositions and physicochemical properties of DF. The bleaching treat- ment induced the greatest changes on DF producing yellow cellulose-rich fibre concentrates with improved WHC from 3.2 to 10.0 g/g and improved SWC from 4.0 to 8.8 ml/g. Otherwise, reduction of the particle size influenced hydration properties and colours of DF. WHC and SWC tended to increase with the particle size whereas smaller granulometric size increased the lightness of fibres. Desugaring increased the DF content in both pomaces by 1.2-fold with slight modifica- tion of apple insoluble dietary fibre ratio. Fibre concentrates had improved WHC and SWC up to 1.4-fold. All processes had no significant effect (p < 0.05) on OHC of DF except with ultrafine apple fibre concentrates. Results showed that pro- cessing had overall positive effects on DF contents and hy- dration properties of pomaces from cooked fruits. Bleached fibre concentrates from apple pomace had the highest WHC (10.0 g/g) whereas that of pear had the highest fibre content (89.9 %). Fibres from cooked fruit pomaces may therefore be used as textural ingredients or functional foods. [less ▲]

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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 detailContribution to pomegranate seeds conservation (Punica granatum L.) by osmotic dehydration
Bchir, Brahim ULg

Doctoral thesis (2011)

The aim of this work was to create a complete conservation process of pomegranate seeds (Punica granatum L.). This process is essentially based on osmotic dehydration (OD), which was associated to ... [more ▼]

The aim of this work was to create a complete conservation process of pomegranate seeds (Punica granatum L.). This process is essentially based on osmotic dehydration (OD), which was associated to freezing and air-drying process. Several parameters were studied to optimize the process such as osmotic solution (sucrose, glucose, and sucrose/glucose and date juice with sucrose added), temperature (30, 40, and 50°C) and state of the fruit (fresh and frozen). All these conditions were linked to seed proprieties (texture, structure, and colour). The study of osmotic dehydration parameters (water loss (WL), solids gain (SG) and weight reduction (WR)) showed that most significant changes of mass transfer took place during the first 20 min of dewatering using frozen seeds, independently of temperature and sugar type. During this period, seeds water loss was estimated at 46% in sucrose, 41% in sucrose/glucose mix, 39% in date juice, and 37% in glucose. Mass transfer was slower starting from fresh fruit but led to a higher rate of WL at the end of the process. This fact can be explained by scanning electron microscopy, which showed damage of seed cell structure after freezing. This has practical consequences in terms of the modification of seeds texture. The same process also revealed a modification of seed texture and cell structure after osmotic dehydration. Using a sucrose solution and a temperature of 50°C favoured the best mass transfer. The determination of different water fractions of seed by differential scanning calorimetry (DSC) showed that the % of frozen water decreased 3.5 times contrary the % of unfreezable water that increased 2.5 times. This favours a better seeds conservation. During osmotic dehydration, there was a non negligible leaching of natural solutes from seeds into the solution, which might have an important impact on the sensorial and nutritional value of seeds. Using only osmotic dehydration could not maintain the stability of seeds during conservation. In fact, after the osmotic process, water activity of seeds was found to be higher than 0.9, allowing to the development of microorganisms and some undesirable reactions. As a consequence, a drying of the pomegranate seeds (during four hours) was investigated at three different temperatures (40, 50, and 60 °C) with air flow rate of 2 ms-1. Prior to the drying process, seeds were osmodehydrated in a sucrose solution (55°Brix) during 20 min at 50°C. The drying kinetics and the effects of OD and air-drying temperature on antioxidant capacity, total phenolic, colour, and texture were determined. This work is a contribution to the study of physico-chemical properties of pomegranate seeds (Punica granatum L.) during freezing, osmotic dehydration and drying. After the global process, the pomegranate seed characteristics lead to new industrial developments. [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 [=BASE] (2011), 15(1), 131-144

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

Among the preservation processes of vegetal products, osmotic dehydration presents an economic and a nutritional interest. This technique consumes a low quantity of energy, prolongs the period of availability of foodstuffs, and gives new and appreciated sensory properties to products. Therefore, the producers can sell their productions at better prices and the consumers are able to consume fruits and vegetables throughout the year. 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 present a synthesis of the literature concerning the osmotic dehydration technique, and also to specify the new tendencies and directions of recent research. [less ▲]

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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 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 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 detailOsmotic dehydration of pomegranate seeds: mass transfer kinetics and differential scanning calorimetry characterization
Bchir, Brahim ULg; Souhail, Besbes; Attia, Hamadi et al

in International Journal of Food Science & Technology (2009), 44

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, w⁄ w). 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, w⁄ w). 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 detailContribution to the valorisation of pomegranate (Punica granatum L.)
Bchir, Brahim ULg; Roiseux, Olivier; Attia, Hamadi et al

Poster (2007, October 11)

Detailed reference viewed: 16 (6 ULg)