References of "Attia, Hamadi"
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See detailMilk-clotting properties of plant rennets and their enzymatic, rheological and sensory role in cheese making: a Review
Ben Amira, Amal; Besbes, Souhail; Attia, Hamadi et al

in International Journal of Food Properties (in press)

Plant rennets hold an important position amongst various coagulants used in cheese technology. The selection of a suitable plant coagulant is important due to the increasing global demands of cheese ... [more ▼]

Plant rennets hold an important position amongst various coagulants used in cheese technology. The selection of a suitable plant coagulant is important due to the increasing global demands of cheese alongside reduced supply of calf rennet. Thus, a literature synthesis is presented to investigate recent achievements on their functional properties and enzymatic role in cheese making. Efforts have also been done to compare certain rheological and sensory properties of final products, arising from some plant and animal based rennets. In fact, some coagulants such as actinidin or dubiumin produce cheeses with sensory qualities similar to those produced by animal rennet. Others, like ginger, cucumisin or hieronymain proteases contribute to develop very different textures and flavors, due to excessive proteolytic activity and production of bitter peptides. For milk-clotting enzymes with high non-specific action, several improvement strategies have been developed to produce cheeses with sensory properties close to those of animal rennet. For example, the mixture of coagulants (cardosins/chymosin), the selection of appropriate milk or its ultrafiltration, as well as the increase of salting time of cheese during ripening could be efficient ways to improve texture and reduce bitterness. Concerning cheeses with high yield loss, the whey could be used for a traditional production of whey cheese. To conclude, the selection of appropriate plant rennet with high MCA/PA ratio and the optimization of all coagulation parameters play a central role in manufacturing cheese with superior rheological and sensory properties. [less ▲]

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See detailIdentification of proteins from wild cardoon flowers (Cynara cardunculus L.) by a proteomic approach
Ben Amira, Amal; Bauwens, Julien ULg; De Pauw, Edwin ULg et al

in Journal of Chemical Biology (in press)

Proteomic approach was applied to identify total proteins, particularly the enzymatic content, from wild cardoon flowers. As the selection of an appropriate sample preparation method is the key for ... [more ▼]

Proteomic approach was applied to identify total proteins, particularly the enzymatic content, from wild cardoon flowers. As the selection of an appropriate sample preparation method is the key for getting reliable results, two different extraction/precipitation methods (trichloroacetic acid and phenol/ammonium acetate) were tested on fresh and lyophilized flowers. After two-dimensional electrophoresis (2D–E) separations, a better protein pattern was obtained after phenol extraction from lyophilized flowers. Only 46 % of the total analyzed spots resulted in a protein identification by mass spectrometry MALDI-TOF. Four proteases (cardosins A, E, G, and H), which have become a subject of great interest in dairy technology, were identified. They presented molecular weights and isoelectric points very close and high levels of homology between matched peptides sequences. The absence of the other cardosins (B, C, D, and F) could be an advantage, as it reduces the excessive proteolytic activity that causes bitter flavors and texture defects, during cheese making. [less ▲]

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See detailEffect of extraction pH on techno-functional properties of crude extracts from wild cardoon (Cynara cardunculus L.) flowers
Ben Amira, Amal ULg; Makhlouf, Ines; Petrut, Raul Flaviu et al

in Food Chemistry (2017), 225

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See detailCARACTERISATION STRUCTURALE, FONCTIONNELLE ET ACTIVITE ANTIHYPERTENSIVE DES POLYSACCHARIDES EXTRAITS DES GRAINES DE POIS CHICHE
MOKNI GHRIBI, Abir; SILA, Assaâd; MAKLOUF GAFSI, Ines et al

Poster (2016, April 22)

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See detailEFFECT OF EXTRACTION pH ON PHYSICO-CHEMICAL, ENZYMATIC AND TECHNOLOGICAL PROPERTIES OF CRUDE EXTRACTS FROM WILD CARDOON (CYNARA CARDUNCULUS L.) FLOWERS
BEN AMIRA, Amal; BESBES, Souhail; ATTIA, Hamadi et al

Conference (2016, March 22)

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See detailÉTUDE DES PROPRIETES RHEOLOGIQUES DES PATES A PAIN SANS GLUTEN
DOUIRI, Sabrine; Blecker, Christophe ULg; ATTIA, Hamadi et al

Conference (2016, March 22)

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See detailPURIFICATION ET IDENTIFICATION DE PEPTIDES DOUES D’ACTIVITES BIOLOGIQUES A PARTIR DES HYDROLYSATS PROTEIQUES DE POIS CHICHE
MOKNI GHRIBI, Abir; SILA, Assaâd; PRZYBYLSKIC, Rémy et al

Conference (2016, March 22)

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See detailIMPACT OF EXTRACTION CONDITIONS ON CHEMICAL STRUCTURE, THERMAL PROPERTIES AND ANTIOXIDANT ACTIVITIES OF ULVAN FROM THE GREEN SEAWEED ULVA LACTUCA
Yaich, Hela; Garna, Haikel; Abbès, Fatma et al

Poster (2016, March 21)

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See detailVALORISATION DES ECARTS DE TRIAGE DE DATTES TUNISIENNES: ETUDE DES ACTIVITES ANTIOXYDANTE, ANTIMICROBIENNE ET CYTOTOXIQUE DES ANTIOXYDANTS DE LA PULPE
KCHAOU, Wissal; ABBÈS, Fatma; BEN MANSOUR, Riadh et al

Conference (2016, March 21)

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See detailPollen du palmier dattier: Propriétés physico-chimiques et techno-fonctionnelles
Sebii, Haifa; Bchir, Brahim; Karra, Sirine et al

Poster (2016, March)

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See detailGamma radiation induced modifications of tapioca starch
Atrous, Hager; Benbettaïeb, Nasreddine; Hosni, Faouzi et al

in Asian Academic Research Journal of Multidisciplinary (2016), 3(3), 187-220

The effect of gamma radiation (3, 5, 10, 20, 35 and 50 kGy) on the morphological, structural, physicochemical, pasting and thermal properties of tapioca starch was studied. Microphotographs of scanning ... [more ▼]

The effect of gamma radiation (3, 5, 10, 20, 35 and 50 kGy) on the morphological, structural, physicochemical, pasting and thermal properties of tapioca starch was studied. Microphotographs of scanning electron microscopy and polarized light microscopy revealed the absence of morphological changes induced by gamma radiation. The X-ray diffraction spectra showed that irradiation treatment did not influence the shape and intensity of X-ray diffraction peaks. The presence of free radicals in the irradiated tapioca starch was confirmed by electron spin resonance spectrometry. Fourier transform infrared spectroscopy showed that the irradiated starch displayed a significant decrease in the intensity of the O–H and C–H stretches, bending modes of water and glycosidic linkages. Irradiation improved the water solubility index of starch granules and depressed the apparent amylose content. An increase in the swelling power was observed after irradiation treatment until 20 kGy, followed by a decrease at higher doses. Brabender viscoamylograph test showed that the maximal consistency of the starch paste decreased significantly with increasing irradiation dose. There was no significant difference in the gelatinization temperatures, as well as the corresponding transition enthalpies among native and irradiated tapioca starch samples, as shown in the differential scanning calorimetry thermograms. [less ▲]

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See detailEffect of ultrafiltration process on physico-chemical, rheological, microstructure and thermal properties of syrups from male and female date palm saps
Makhlouf-Gafsi, Ines; Baklouti, Samia; Mokni, Abir et al

in Food Chemistry (2016), 203

This study investigates the effect of the ultrafiltration process on physicochemical, rheological, microstructure and thermal properties of syrups from male and female date palm sap. All the studied ... [more ▼]

This study investigates the effect of the ultrafiltration process on physicochemical, rheological, microstructure and thermal properties of syrups from male and female date palm sap. All the studied syrups switched from pseudoplastic rheological behaviour (n = 0.783) to Newtonian behaviour (n〰1) from 10 to 50 s‾1 respectively and present similar thermal profiles. Results revealed that the ultrafiltration process significantly affects the rheological behaviour of the male and female syrups. These differences on rheological properties are attributed to the variation of chemical composition between sap and sap permeate syrups. Furthermore, the effect of temperature on viscosity of the syrups was investigated during heating and cooling processes at the same shear rate (50 s 1). This study provides idea of the stability of the syrup by evaluating the area between heating and cooling curves. Actually, the syrup prepared from male sap permeate is the most stable between the four studied syrups. [less ▲]

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See detailPhysico-chemical properties and amino acid profiles of sap from Tunisian date palm
Makhouf-Gafsi, Ines; Mokni-Ghribi, Abir; Brahim, Bchir et al

in Scientia Agricola (2016), 73(1), 85-90

Date palm sap (Phoenix dactylifera L.), also known as "legmi", is a fresh juice ex¬tracted from date palm trees. The present study aimed to elucidate the effects of collection time (at the beginning of ... [more ▼]

Date palm sap (Phoenix dactylifera L.), also known as "legmi", is a fresh juice ex¬tracted from date palm trees. The present study aimed to elucidate the effects of collection time (at the beginning of the tapping period and after seven days of collection) on the amino acid profile and physico-chemical properties of date palm sap from both male and female trees. Dry matter, protein, amino acid, and sugar profiles were determined using the Kjeldahl method, High-Performance Liquid Chromatography (HPLC), and High-Performance Anion-Exchange Chro¬matography with Pulsed Amperometric Detection (HPAEC-PAD), respectively. Date palm sap from both male and female trees contained high levels of carbohydrates. HPLC analysis showed that this fraction was dominated by sucrose in the sap sample from female trees compared to that from male trees. Male date palm sap was noted to exhibit lower dry matter content than female date palm sap but higher protein, total polyphenol, ash, and amino acid contents. While the major essential amino acids in the sap from male trees consisted of valine and threonine, they were represented by lysine and phenylalanine in sap samples from female trees. Further, Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) analysis showed the presence of a proteinic band of 30 kDa only for the sap from male trees. Taken together, the sap from both male and female date palm trees had a number of properties that are highly valued by the functional food industry. [less ▲]

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See detailPhenolic profile, antibacterial and cytotoxic properties of second grade date extract from Tunisian cultivars (Phoenix dactylifera L.)
Kchaou, Wissal; Abbès, Fatma; Ben Mansour, Riadh et al

in Food Chemistry (2016), (194), 1048-1055

The present study aimed to investigate the phenolic profile of second grade date extracts and evaluate their antimicrobial and cytotoxic activities with regard to some pathogenic microorganisms. Phenolic ... [more ▼]

The present study aimed to investigate the phenolic profile of second grade date extracts and evaluate their antimicrobial and cytotoxic activities with regard to some pathogenic microorganisms. Phenolic content was analyzed by HPLC. Antimicrobial activity was evaluated by the agar disk diffusion method, and in vitro cytotoxic activity was examined by cell proliferation assay. The results revealed that second grade dates presented three benzoic acids, five cinnamic acids and two flavonoids, with the predominance of q-coumaric acid (1998.80 lg/100 g). The antimicrobial activities showed that the date extracts were active against Gram (+) and Gram (-) bacteria, showing marked activity against Escherichia coli with an inhibition zone of 25 mm. Cytotoxicity assays showed that the date extracts were able to inhibit the proliferation of HeLa cell lines. The results confirmed that the date extracts were rich in biologically active compounds that are highly valued in the functional food and nutraceutical industries. [less ▲]

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See detailEffect of γ-radiation on free radicals formation, structural changesand functional properties of wheat starch
Atrous, Hager; Benbettaieb, Nasreddine; Hosni, Faouzi et al

in International Journal of Biological Macromolecules (2015), 80

Wheat starch was treated by different γ-radiation doses (3, 5, 10, 20, 35 and 50 kGy). The effects of γ-radiation on structural, thermal, physicochemical, morphological and rheological properties of wheat ... [more ▼]

Wheat starch was treated by different γ-radiation doses (3, 5, 10, 20, 35 and 50 kGy). The effects of γ-radiation on structural, thermal, physicochemical, morphological and rheological properties of wheat starch were studied. The presence of free radicals after γ-radiation treatment, which number decreased with time was confirmed. Structural analysis revealed decreases in the intensities of the O–H and C–H stretches and glycosidic linkages indicating the depolymerization of amylose and probably amy-lopectin into shorter chain molecules, but showed that γ-radiation treatment did not affect the crystalline structure. Differential scanning calorimetric (DSC) thermograms showed the absence of significant differences in the gelatinization temperatures, as well as the corresponding transition enthalpies since the DSC parameters are related to the crystalline ordering within the granules. Apparent amylose content decreased linearly with increasing irradiation dose leading to an increase in water solubility index. Anincrease in the swelling power was observed after irradiation treatment until 20 kGy, followed by a rapiddecrease at higher doses. Microscopic observations showed that the effect of γ-radiation was more visible on starch pastes than on starch granules. Rheological properties of the starch pastes decreased within creasing irradiation dose as a result of glycosidic bond cleavage. [less ▲]

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See detailEffect of drying methods on physico-chemical and functional properties of chickpea protein concentrates
Ghribi, Abir Mokni; Maklouf Gafsi, Ines; Blecker, Christophe ULg et al

in Journal of Food Engineering (2015), 165

Chickpea protein concentrates (CPCs) were prepared from seed flour by alkaline extraction followed by isoelectric precipitation. The effects of different drying methods (freeze drying and convective ... [more ▼]

Chickpea protein concentrates (CPCs) were prepared from seed flour by alkaline extraction followed by isoelectric precipitation. The effects of different drying methods (freeze drying and convective drying at 40 °C and 50 °C) on physico-chemical and functional properties of CPCs were investigated. CPCs were found to have high contents of protein (61.20–63.12% dry weight basis). Freeze dried concentrate had the highest values of water and oil holding capacities. This drying method gave the lightest CPCs color. The amino acid of CPCs could reach the FAO/WHO requirement (1990) for the essential amino acids for preschool children and the sulfur-containing amino acids were the first limiting amino acids for all three protein concentrates. The solubility-pH profile of different CPCs showed minimum solubility when the pH was between 4.0 and 5.0. All concentrates were able to decrease the interfacial tension. The thermal properties of CPCs were studied by differential scanning calorimetry. CPCs differed significantly (p ≤ 0.05) in peak denaturation temperature and enthalpy of transition. Hence, drying methods used for the preparation of CPCs powders can affect the physico-chemical and functional properties. [less ▲]

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See detailFoamability and Foam Stability of Male and Female Date Palm Sap (Phoenix dactylifera L.) During the Collection Period
Makhlouf-gafsi, Ines; Mokni-ghribi, Abir; Bchir, Brahim et al

in Food Biophysics (2015)

This work aimed to study the influence of date palm sex on the surface properties of date palm sap (DPS) (Phoenix dactylifera L.) during the collection period. The behavior at the interface and foaming ... [more ▼]

This work aimed to study the influence of date palm sex on the surface properties of date palm sap (DPS) (Phoenix dactylifera L.) during the collection period. The behavior at the interface and foaming properties were evaluated via equilibrium surface tension (drop volume) and bubbling method, respectively. Unlike male sap, the female sap was unable to produce foam due to its low rate of adsorption, low average hydrophobicity values, and low bulk viscosity values throughout the collection period. For male sap, there are significant differences (p<0.05) on foaming properties throughout the collection period. In fact, the last 3 weeks of sap collection were characterized by a decrease pace of surface tension which explains the enhancement of both foam capacity and stability. The last week of collection period present the best foam power (0.9). To explain these differences, the interactions of several factors and their affects on foaming properties were examined. Results showed a positive correlation between foam capacity and average hydrophobicity values. In the other hand, foam stability exhibits a positive correlation with the increase of protein concentration and bulk viscosity. [less ▲]

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See detailEffects of enzymatic hydrolysis on conformational and functional properties of chickpea protein isolate
Ghribi, Abir Mokni; Maklouf Gafsi, Ines; Sila, Assaâd et al

in Food Chemistry (2015), 187

The impact of enzymatic hydrolysis by Alcalase on the conformational and functional properties of chickpea protein isolate (CPI) was investigated. The physicochemical, interfacial tension and surface ... [more ▼]

The impact of enzymatic hydrolysis by Alcalase on the conformational and functional properties of chickpea protein isolate (CPI) was investigated. The physicochemical, interfacial tension and surface characteristics of CPI and their hydrolysates (CPH) according to the degree of hydrolysis (DH) were also determined. These parameters were then related to the changes in the emulsification activity (EAI) and stability (ESI). The enzymatic hydrolysis was found to improve protein recovery and solubility, leading to a reduction in the molecular weight bands with a concomitant increase in the intensity and appearance of protein bands having apparent molecular mass below 20 kDa. The interfacial tension decreased from _66.5 mN m_1 for CPI to _59.1 mN m_1 for CPH. A similar trend was observed for the surface charge which declined from _27.55 mV to _16.4 mV for the CPI and CPH, respectively. These changes were found to have a detrimental effect on the EAI and ESI values. [less ▲]

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