Time filter

Source Type

Arafa S.,Ecole Superieure des Industries Alimentaires de Tunis | Chouaibi M.,Ecole Superieure des Industries Alimentaires de Tunis | Sadok S.,Institute National Des Science Et Technologies Of La Mer | El Abed A.,Institute National Des Science Et Technologies Of La Mer
The Scientific World Journal | Year: 2012

Seasonal variation in the gonad weight and biochemical composition of the sea urchin Paracentrotus lividus from the Golf of Tunis (Tunisia) were studied between September 2003 and August 2004. The highest gonad indices occurred in March (16.71%). The spawning period occurred between April and July and resulted in a fall in gonad indices to low level (7.12 ± 0.12). Protein constituted the main component of the gonad, and lipid and carbohydrate were found at appreciable amounts. Consistent with the gonad cycle, sea urchin biochemical components showed clear seasonal variation with a significant decrease during the spawning period. The polyunsaturated fatty acid (PUFA) group was found at high level (40% of the total fatty acids). Of the PUFA group, eicosapentaenoic (C20:5 n-3) and eicosatetraenoic (C20:4 n-3) were the most abundant gonadal lipids. The level of PUFA was significantly affected by temperature variation showing an increase during the cold months and a decrease in the hot months. Copyright © 2012 Soumaya Arafa et al.


Bornaz S.,Ecole Superieure des Industries Alimentaires de Tunis | Guizani N.,Sultan Qaboos University | Fellah N.,Ecole Superieure des Industries Alimentaires de Tunis | Sahli A.,Institute National Agronomique Of Tunisie | And 2 more authors.
International Journal of Food Properties | Year: 2010

The coagulation of ewe's milk was studied by using plant source coagulants namely the artichoke, Cynara scolymus L. cv. Blanca, and latex from the fig tree (Ficus carica L.). A turbidimetric method was used to evaluate and compare the coagulation properties of the novel coagulants with chymosin treated samples. Syneresis capacity and sensory evaluation of resultant cheese samples were studied and it was found that both cynara and chymosin produced sigmoidal increase in turbidity to the milk with three distinct phases. The coagulation kinetics was affected substantially by both coagulants. Plant coagulant induced shorter gelation time compared to chymosin however required longer time for restructuration (end of coagulation). The coagulum obtained with the latex of Ficus carica had a higher yield, owing to its high water retention capacity. With the exception of color, the overall sensory attributes did not show significant differences among coagulants.


Bornaz S.,Ecole Superieure des Industries Alimentaires de Tunis | Guizani N.,Sultan Qaboos University | Allouch W.,Ecole Superieure des Industries Alimentaires de Tunis | Sahli A.,Institute National Agronomique Of Tunisie | Attia H.,University of Sfax
International Dairy Journal | Year: 2010

Due to its numerous benefits, including health-promoting characteristics, there is increasing interest in finding product applications for mares' milk. In the present study, the physicochemical properties, turbidity and conductivity of Arabian mares' milk were studied during acidification by fermentation at 30 °C and compared with those of bovine milk. The data for the acidification rate were modelled using a logistic equation. Mares' milk showed a longer latency phase (284 min) and lower acidification rate (μmax = 0.0052 dpH min-1) compared with bovine milk (194 min and 0.0098 dpH min-1 respectively). The general shape of the curves of the turbidity versus time and pH were similar in nature for the acidification of both milks. However, the characteristic points were different, due to the differences in casein micelle composition. Measurement of electrical conductivity during acidification showed that maximum demineralization of casein micelles started around pH 6.09 and 5.31, for mares' and bovine milk, respectively. In conclusion, the technological characteristics of mares' milk were very different from those of bovine milk, due to intrinsic physicochemical properties of both milks. © 2010 Elsevier Ltd. All rights reserved.


PubMed | Ecole Superieure des Industries Alimentaires de Tunis and Center de Biotechnologie de la Technopole de Borj-Cedria
Type: | Journal: Food chemistry | Year: 2015

Juices from conventionally and organically grown Citrus sinensis (L.) Osbeck cv. Maltaise demi-sanguine blood orange were investigated for quality parameters and antioxidant capacity. This blood orange variety is particularly rich in linoleic, linolenic acids, vitamin C and phenolic compounds. The quantitative determination of these compounds in cv. Maltaise demi-sanguine juice produced under conventional and organic agricultural practices revealed significant differences. The organically grown fruits contained more hesperidin and total fatty acids amounts as well as a higher sugar content and a lower acidity. Conventionally-grown fruit was found to have an increase in antioxidant capacity. In addition to having higher antioxidant activity conventionally-grown fruit had an observed increase in the concentration of phenolic acids and most flavonoids. The results of this study indicated that organically-grown Maltaise demi-sanguine juice contained an increased concentration of hesperidin which has been observed to possess biological activities associated with a healthy life.


Lakoud A.,Ecole Superieure des Industries Alimentaires de Tunis | Curet S.,French National Center for Scientific Research | Hassouna M.,Ecole Superieure des Industries Alimentaires de Tunis
International Food Operations and Processing Simulation Workshop, FoodOPS 2015 | Year: 2015

This study focuses on the hydration process of dates from experimental and numerical investigations. Dry Tunisian Deglet Nour dates were hydrated at a laboratory scale by using saturated air. A theoretical model based on a finite element scheme was developed to describe mass transfer phenomena that occur during the hydration process. This model considers the real shape of dates with a 2D axisymmetric analysis. Both moisture diffusivity and convective mass transfer coefficient of dates were estimated by using an optimization algorithm based on a least square approach from experimental and numerical average moisture contents. Overall, the experimental moisture contents as a function of hydration time were found in good agreement with the simulated values for various operating conditions. Such a methodology can now be used as a predictive tool to simulate the hydration of dates in order to improve the quality of final product and reducing processing time. © 2015 DIME UNIVERSITÀ DI GENOVA.


Guizani N.,Muscat College | Al-Saidi G.S.,Muscat College | Rahman M.S.,Muscat College | Bornaz S.,Ecole Superieure des Industries Alimentaires de Tunis | Al-Alawi A.A.,Muscat College
Journal of Food Engineering | Year: 2010

The state diagram of Deglet Nour dates was developed using freezing curve, glass transition line, and maximal-freeze-concentration condition. Freezing points and glass transition temperature were measured by differential scanning calorimetry (DSC) as a function of water content. Freezing points were fitted to the Clausius-Clapeyron equation adjusted with un-freezable water, and glass transition was fitted to the Gordon-Taylor model. Glass transition decreased with a decrease in solids content, confirming the plasticizing effect of water on date solids. Freezing point data indicated the temperature when ice formed and dates would be most stable in terms of its deterioration if it can be stored below its glass transition. Maximum-freeze-concentration conditions was found as Xs ′ (characteristic solids content) = 0.78 g/g sample, with the characteristic temperature as Tg ′ (characteristics glass transition) = -48 °C and Tm ′ (characteristic end point of freezing) = -38.2 °C. These characteristics indicated that 0.22 g/g sample water in date was un-freezable (i.e. bound with solids or unable to form ice). The developed state diagram can be used in determining the stability of dates during storage as a function of temperature and moisture content. Moreover, it can be used to determine optimum drying and freezing conditions. © 2010 Elsevier Ltd. All rights reserved.


Khemakhem M.,Ecole Superieure des Industries Alimentaires de Tunis | Khemakhem M.,Tunis el Manar University | Sotiroudis G.,National Hellenic Research Foundation | Mitsou E.,National Hellenic Research Foundation | And 5 more authors.
Journal of Molecular Liquids | Year: 2016

A natural melanin and humic acid-like polymer complex from olive mill waste waters (OMWWs) showing surfactant and antiradical properties was encapsulated in food grade water-in-oil (W/O) microemulsions to detect potential interactions with the system's components. Before encapsulation, putative surfactant properties of the polymer complex were investigated through interaction studies with the cationic dye Toluidine blue O (TBO) using spectrophotometry. The limits of the single-phase region corresponding to W/O microemulsions as described by ternary phase diagrams were studied. Structural characteristics of the microemulsions were examined using electrical conductivity, dynamic light scattering (DLS) and electron paramagnetic resonance (EPR) spectroscopy. Antiradical properties of encapsulated polymer complex were investigated using an EPR approach. The existence of a J-aggregation mechanism consisting of head-to-tail arrangement of the dye molecules was proved and attributed to a specific 3D-arrangement of the phenolic constituents of the complex. EPR measurements using the spin probing technique revealed participation of the complex in the surfactants monolayer causing increased membrane fluidity. Droplet size measurements showed a decrease of aqueous droplets size from 19 ± 0.5 to 17 ± 0.8 nm upon polymer complex addition. Finally, radical scavenging activity of the complex was retained upon encapsulation and expressed in Trolox equivalents. © 2016 Elsevier B.V.


Khemakhem M.,Ecole Superieure des Industries Alimentaires de Tunis | Khemakhem M.,Tunis el Manar University | Papadimitriou V.,National Hellenic Research Foundation | Sotiroudis G.,National Hellenic Research Foundation | And 5 more authors.
Food Chemistry | Year: 2016

A water soluble humic acid and melanin-like polymer complex (OMWW-ASP) was isolated from olive mill waste waters (OMWW) by ammonium sulfate fractionation to be used as natural additive in food preparations. The dark polymer complex was further characterized by a variety of biochemical, physicochemical and spectroscopic techniques. OMWW-ASP is composed mainly of proteins associated with polyphenols and carbohydrates and the distribution of its relative molecular size was determined between about 5 and 190kDa. SDS-PAGE shows the presence of a well separated protein band of 21.3kDa and a low molecular weight peptide. The OMWW-ASP complex exhibits a monotonically increasing UV-Vis absorption spectrum and it contains stable radicals. Antioxidant activity measurements reveal the ability of the OMWW protein fraction to scavenge both the cationic 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radical, as well as the stable nitroxide free radical 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPOL). © 2016 Elsevier Ltd.


PubMed | Ecole Superieure des Industries Alimentaires de Tunis
Type: Journal Article | Journal: Food science and technology international = Ciencia y tecnologia de los alimentos internacional | Year: 2012

The physicochemical components and functional properties of the gum exudates from the trunk of the almond tree (Prunus dulcis) have been investigated, along with the emulsification and foaming properties. The gum exudates are composed on dry weight basis by 2.45% of proteins, 0.85% of fats and 92.36% of carbohydrates. The latter consist of arabinose, xylitol, galactose and uronic acid (46.8:10.9:35.5:6.0 mass ratio) with traces of rhamnose, mannose and glucose. Moreover, gum exudates are rich in minerals, such as sodium, potassium, magnesium, calcium and iron. The emulsifying capacity was studied for a 20% w/w olive oil in water emulsion as a function of gum concentration (from 3% to 12% w/w in the aqueous phase) as well as pH levels (from 3.0 to 10.0). The most stable and homogeneous emulsion was prepared with an 8% w/w aqueous almond gum solution at a pH between 5.0 and 8.0. In particular, for the same formulation, the emulsion processed by high pressure homogenization (5 passes at 200MPa) resulted to be extremely stable under accelerated ageing, exhibiting no significant change in droplet size distribution for 14 days at 55C. All the tested systems exhibited an extremely low foaming capacity.


PubMed | Ecole Superieure des Industries Alimentaires de Tunis
Type: | Journal: TheScientificWorldJournal | Year: 2012

Seasonal variation in the gonad weight and biochemical composition of the sea urchin Paracentrotus lividus from the Golf of Tunis (Tunisia) were studied between September 2003 and August 2004. The highest gonad indices occurred in March (16.71%). The spawning period occurred between April and July and resulted in a fall in gonad indices to low level (7.12 0.12%). Protein constituted the main component of the gonad, and lipid and carbohydrate were found at appreciable amounts. Consistent with the gonad cycle, sea urchin biochemical components showed clear seasonal variation with a significant decrease during the spawning period. The polyunsaturated fatty acid (PUFA) group was found at high level (40% of the total fatty acids). Of the PUFA group, eicosapentaenoic (C20:5 n - 3) and eicosatetraenoic (C20:4 n - 3) were the most abundant gonadal lipids. The level of PUFA was significantly affected by temperature variation showing an increase during the cold months and a decrease in the hot months.

Loading Ecole Superieure des Industries Alimentaires de Tunis collaborators
Loading Ecole Superieure des Industries Alimentaires de Tunis collaborators