Institute Superieur Of Biotechnologie Of Sidi Thabet

Sidi Bou Saïd, Tunisia

Institute Superieur Of Biotechnologie Of Sidi Thabet

Sidi Bou Saïd, Tunisia
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Bellili S.,Manouba University | Bellili S.,University of Carthage | Jazi S.,Manouba University | Jazi S.,University of Carthage | And 10 more authors.
Main Group Chemistry | Year: 2017

In the present paper, the essential oil and the volatiles emitted in vivo by leaves of A. herba alba, which grows wild in center of Tunisia, were analyzed by GC-MS and SPME, respectively. The essential oil was characterized by the predominance of oxygenated monoterpenes (93.3) with α-thujone as the major compound (45.5) followed by β-thujone (11.4), trans-sabinyl acetate (10.1) and 1,8-cineole (7.4). The SPME analyses showed that oxygenated monoterpenes were the most representative compounds (64.9). The major ones were α-thujone (37.9), germacrene D (16.5), 1,8-cineole (8.4) followed by β-thujone (7.8). Moreover, different activities (antioxidant, antibacterial, allelopathic and insecticidal) of the leaf essential oil were investigated. The antioxidant activity was ascertained by evaluating its inhibitory effect against DPPH and ABTS. The results showed that the essential oil had a strong activity and it was more effective against the DPPH radical (IC50=6μg/mL) than the ABTS radical (IC50=40μg/mL). In antibacterial screening, it inhibited the growth of all bacteria tested except Salmonella anatum and Salmonella salamae which were resistant to this oil type. Staphylococcus aureus and Vibrio cholera were found to be extremely sensitive with the lowest MIC value (0.007mg/mL). In addition, allelopathic activity was evaluated against Lactuca sativa and Raphanus sativus. Data showed that, with essential oil, seed germination was completely inhibited for both of them, suggesting a potent allelopathic potential for the evaluated oil. Insecticidal activity was investigated against Culex pipiens larvae and a weak activity (LC50 241.1ppm) for this A. herba alba essential oil. © 2017 - IOS Press and the authors. All rights reserved.

Yaich H.,University of Sfax | Garna H.,Institute Superieur Of Biotechnologie Of Sidi Thabet | Besbes S.,University of Sfax | Barthelemy J.-P.,University of Liège | And 3 more authors.
Food Hydrocolloids | Year: 2014

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 hydrocolloids demonstrated a pseudoplastic behavior. Viscoelastic behavior was carried out at a concentration of 1.6% (w/v) in the presence of 7mM 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. © 2014 Elsevier Ltd.

Yaich H.,University of Sfax | Garna H.,Institute Superieur Of Biotechnologie Of Sidi Thabet | Bchir B.,University of Liège | Besbes S.,University of Sfax | And 4 more authors.
Algal Research | Year: 2015

Nowadays there is a growing trend to find new sources of dietary fibre (DF), such as marine algae by-products that have traditionally been undervalued. In this respect, the aim of the present investigation was firstly to compare two methods of dietary fibre quantification (Englyst and Prosky) and secondly to determine the chemical composition and some of the functional properties of total and insoluble fibres extracted in accordance with the Englyst method. The dietary fibres of dried Ulva lactuca collected from the Tunisian littoral were determined by the Prosky (gravimetric method) and Englyst (enzymatic-chemical method) methods. The two extraction methods (Englyst-Prosky) provided approximately the same values in total fibres (~ 54%). However, they had different insoluble and soluble fibre contents. U. lactuca contained 20.53% and 31.55% of soluble fibres and 34.37% and 21.54% of insoluble fibres using the Prosky and Englyst methods, respectively. The fractionation of the insoluble dietary fibre concentrate revealed that hemicellulose was the most abundant fraction (32.49%), followed by cellulose (16.59%) and "lignin-like" compounds (1.53%). For both fibre concentrates, the main neutral sugar was glucose (20.70%-27.59%), which corresponded to hemicellulose and cellulose. The water holding capacity of insoluble fibre concentrate was relatively high. It varied between 9.32. g and 10.3. g of water/g of dry fibre at 25. °C and 80. °C, respectively. Nevertheless, the oil holding capacity of the insoluble fibre concentrate was not affected by temperature. It was about 1.08 and 1.01. g of oil/g of dry fibre at 25. °C and 80. °C. Despite the significant functional properties of fibre concentrate, the presence of lead limits its use as an ingredient in the food industry. © 2015 Elsevier B.V.

Mnif W.,University of Monastir | Mnif W.,Institute Superieur Of Biotechnologie Of Sidi Thabet | Hassine A.I.H.,University of Monastir | Bouaziz A.,University of Monastir | And 3 more authors.
International Journal of Environmental Research and Public Health | Year: 2011

Endocrine disrupting chemicals (EDC) are compounds that alter the normal functioning of the endocrine system of both wildlife and humans. A huge number of chemicals have been identified as endocrine disruptors, among them several pesticides. Pesticides are used to kill unwanted organisms in crops, public areas, homes and gardens, and parasites in medicine. Human are exposed to pesticides due to their occupations or through dietary and environmental exposure (water, soil, air). For several years, there have been enquiries about the impact of environmental factors on the occurrence of human pathologies. This paper reviews the current knowledge of the potential impacts of endocrine disruptor pesticides on human health. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

Roig B.,University of Nimes | Mnif W.,University of Monastir | Mnif W.,Institute Superieur Of Biotechnologie Of Sidi Thabet | Hadj Hassine A.I.,University of Monastir | And 5 more authors.
Critical Reviews in Environmental Science and Technology | Year: 2013

Concerns over the threats posed by a large number of molecules, collectively termed as endocrine disrupting compounds (EDCs) and generally known to alter and disrupt hormone systems and physiological functions, have often been expressed in academic and scholarly debates. From the perspective of classical toxicology, EDCs have genomic mechanisms of actions and exert agonistic or antagonistic effects on steroid receptors. They are also able to alter reproductive function by binding to estrogen or androgen receptors, and the neuroendocrine system by binding to the thyroid receptor. Recently, EDCs have been shown to have equally complex nongenomic mechanisms, altering steroid synthesis or steroid metabolism. As environmental contaminants, these molecules proved disruptively harmful for many wildlife species, particularly those from or depending on the aquatic ecosystem. An increasingly growing body of research has voiced further concerns that human populations are not immune from the dangers of EDCs. Studies from this line of research caution that EDCs can alter hormonal balance and that a whole range of breast and prostate cancers, endometriosis, cryptorchidism, and hypospadias have been linked to exposure to EDCs. This particular area has raised a lot of controversy and the literature on this subject often presents opposing, and sometimes conflicting, perceptions and perspectives. Accordingly, the authors aimed to contribute to the committed academic search for better appreciation of the topic. They first discuss the major natural and synthetic chemicals with endocrine disrupting properties to which humans and wildlife may be exposed. They then describe the key endocrine mechanisms of action and conclude by addressing the main observed effects in human and wildlife populations. © 2013 Copyright Taylor and Francis Group, LLC.

Tir M.,Tunis el Manar University | Rebeh I.,Tunis el Manar University | Telahigue K.,Tunis el Manar University | Hajji T.,Institute Superieur Of Biotechnologie Of Sidi Thabet | And 2 more authors.
JAOCS, Journal of the American Oil Chemists' Society | Year: 2015

The goal of this study was to evaluate the chemical composition and the fatty acid profile of mantle and tentacle of male and female Sepia officinalis, sampled at four seasons from the Mediterranean sea of Tunisia. S. officinalis were found to be rich in glycogen, protein and oil, and significant differences were observed between samples. The level of saturated fatty acid and unsaturated fatty acid showed significant variability among sex and during seasons. DHA and EPA, as polyunsaturated fatty acids, were the most abundant in all samples (14.8-27.8 % and 10.4-18.3 %, respectively). Oleic acid was the most abundant monounsaturated fatty acids (1.63-4.52 %). ∑n3 and ∑n6 was remarkably different between seasons and among sex. This study could be suitable for the development of reliable guide of fatty acid accumulation in cephalopod. © 2015 AOCS.

Garna H.,Institute Superieur Of Biotechnologie Of Sidi Thabet | Emaga T.H.,University of Liège | Emaga T.H.,African Research Center on Bananas and Plantains | Robert C.,University of Liège | Paquot M.,University of Liège
Food Hydrocolloids | Year: 2011

A new technique for the purification of pectins using protein (sodium caseinate) was developed and that could replace the process of ethanol which is currently used in industries. Commercial pectins were used as a model to verify the feasibility of the process and to define some important parameters. The results indicated that this purification technique is based primarily on the electrostatic interactions between these two polymers. The electrostatic interactions were strongly dependent on pH and salt concentration. The maximum pectin precipitation was obtained at pH 3.5. At this pH, the pectin acquires a negative charge while the protein is positively charged, promoting thus their attractions. Furthermore, the dissociation of the pectin-caseinates complex and the precipitation of caseinate at pH 4.6 were observed in the presence of salt. This method is very specific, suggesting that it could be used to purify some electrically charged polysaccharides. © 2010 Elsevier Ltd.

Happi Emaga T.,University of Liège | Happi Emaga T.,African Research Center on Bananas and Plantains | Garna H.,Institute Superieur Of Biotechnologie Of Sidi Thabet | Paquot M.,University of Liège | Deleu M.,University of Liège
Food Hydrocolloids | Year: 2012

The binding of sodium caseinate to pectin using Isothermal Titration Calorimetry (ITC) under different pH values (2, 3, 3.5), and comparison of two purification processes (sodium caseinate or ethanol), based on the physicochemical characteristics of purified pectin was evaluated. The results indicated that ITC titration confirmed the existence of interactions between caseinates and pectin at pH 3 and 3.5. The interaction depicts two interdependent steps, one attributed to an electrostatic interaction and another related to a co-acervation mechanism. The chemical characteristics of pectins are strongly dependent on the purification process. Under some extraction conditions, ethanol is not specific to the recovery of pectin since it causes the precipitation of other compounds together with this polysaccharide.However, compared to the caseinate, it allows total precipitation of pectins extracted, but caseinates have the advantage of being more specific for the charged polymers. © 2012 Elsevier Ltd.

Climate change and population growth are expected to exacerbate the water crisis of Mediterranean African Countries (MACs), where agriculture accounts for 80-85% of freshwater consumption. The aim of MADFORWATER is to develop a set of integrated technological and management solutions to enhance wastewater treatment, reuse for irrigation and water efficiency in agriculture in three MACs (Tunisia, Morocco and Egypt). MADFORWATER will develop and adapt to three main hydrological basins in the selected MACs technologies for the production of irrigation-quality water from drainage canals, municipal, agro-industrial and industrial wastewaters, and technologies for water efficiency and reuse in agriculture, initially validated at laboratory scale. Selected technologies will be further adapted and validated in four field pilot plants of integrated wastewater treatment/reuse. Integrated strategies for wastewater treatment and reuse targeted to the selected basins will be developed, and guidelines for the development of integrated water management strategies in other basins of the three target MACs will be produced, considering climate change, population increase and economic growth scenarios. The social and technical suitability of the developed technologies and non-technological instruments in relation to the local context will be evaluated with the participation of MAC stakeholders and partners. Guidelines on economic instruments and policies for the effective implementation of the proposed water management solutions in the target MACs will be developed. The project will lead to a relevant long-term impact in Egypt, Morocco and Tunisia in terms of increased wastewater treatment, wastewater reuse, food production and income in the agricultural and water treatment sectors, and decreased groundwater exploitation, water pollution and food contamination. The MADFORWATER consortium consists of 18 partners, 5 of which from the 3 MACs and 1 from China.

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