EMNA AMMAR - Academia.edu (original) (raw)

Papers by EMNA AMMAR

International Journal of Food Properties, Feb 25, 2011

Olive leaves, an agricultural waste, have great potential as a natural antioxidant. The current s... more Olive leaves, an agricultural waste, have great potential as a natural antioxidant. The current study was made to assess the antioxidant and antimicrobial activities of both the individual and combined phenolics in olive leaf extract. A combined phenolics mixture was prepared by amount ratios of the phenolic compounds in the olive leaf extract. The results showed that both the individual and combined phenolics exhibited good radical scavenging abilities, and also revealed superoxide dismutase (SOD)-like activity. In terms of antimicrobial activity, both oleuropein and caffeic acid showed inhibition effects against microorganisms. Furthermore, the antimicrobial effect of the combined phenolics was significantly higher than those of the individual phenolics. These results show that the combination of olive leaf extract phenolics possessed antioxidant and antimicrobial activities. This study indicates that olive leaf extract might be a valuable bioactive source, and would seem to be applicable in both the health and medical food.

Extremophiles, Jul 16, 2022

The draft genome sequences of five archaeal strains, isolated from Sfax solar saltern sediments a... more The draft genome sequences of five archaeal strains, isolated from Sfax solar saltern sediments and affiliated with Halobacterium salinarum, were analyzed in order to reveal their adaptive strategies to live in hypersaline environments polluted with heavy metals. The genomes of the strains (named AS1, AS2, AS8, AS11, and AS19) are found to contain 2,060

Natural Science, 2013

The essential oil composition of Thymus vulgaris L. and Rosmarinus officinalis L. endemic to Fran... more The essential oil composition of Thymus vulgaris L. and Rosmarinus officinalis L. endemic to France were determined by GC and GC-MS. Oils were assessed for their cytotoxic, antioxidant and antimicrobial activity. 31 and 37 different compounds were identified representing 99.64% and 99.38% of the thyme and rosemary oils respectively, where oxygenated monoterpenes constituted the main chemical class. Thymol (41.33%) and 1.8-cineole (24.10%) were identified as the main constituents of T. vulgaris L. and R. officinalis L., respectively. Essential oils (EOs) of selected plant species were evaluated for their in vitro cytotoxicity against the human lung adenocarcinoma epithelial cell line (A549). Cytotoxicity was measured using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphynyltetrazolium bromide] colorimetric assay. Dose-dependent studies revealed IC 50 of 8.50 ± 0.01 µg/mL and 10.50 ± 0.01 µg/mL after 72 h on the A549 cells for R. officinalis L. and T. vulgaris L., respectively. Antioxidant activity was determined using a quantitative DPPH (1,1-diphenyl-2-picryl hydrazyl) assay. Thymus and rosemary EOs exhibited effective radical scavenging capacity with 50% inhibitory concentration (IC 50) of 437 ± 5.46 µg/mL and 189 ± 2.38 µg/mL respectively and therefore acts as a natural antioxidant agent. The antimicrobial activity of these species has also been studied against several foodborne pathogens and food isolated Salmonella spp. including S. enteritidis of significant importance. According to the results, T. vulgaris L. showed higher bactericidal effect than those from R. officinalis L. These results suggest that the essential oil from T. vulgaris L. and R. officinalis L. have potential to be used as a natural cytotoxic, antioxidant and antimicrobial agent in food processing.

Comptes Rendus Chimie, Sep 1, 2007

This study deals with the valorisation of medicinal and aromatic plants of the Tunisian flora, in... more This study deals with the valorisation of medicinal and aromatic plants of the Tunisian flora, in order to find new bioactive natural products. The essential oil constituents from the flowers of Allium roseum var. odoratissimum, a North African endemic species growing in the ...

E3S web of conferences, 2023

Salinity problems reduce productivity on both irrigated and non-irrigated agricultural lands. Sal... more Salinity problems reduce productivity on both irrigated and non-irrigated agricultural lands. Saline soils occur in arid and semi-arid regions where rainfall is insufficient to meet the crops' water requirements and leach mineral salts out of the root-zone. Compost can play an important role in managing, mitigating, and improving the soil salinity negative effects. In this work, the compost effects on salt affected soil were studied. Therefore, physico-chemical parameters and morphological status of the plants divided into four plots in a greenhouse were studied. The first plot P0 is a control plot which was irrigated by fresh water, P1 was irrigated with fresh water mixed with compost, P2 and P3 were irrigated by saline water with an NaCl concentration of 5 g/L. An automated irrigation system was implemented to manage plots irrigation. The system was based on an electronic board and multiple sensors to track ambient temperature and humidity in the greenhouse, soil moisture and temperature of each plot, data was stored in a SD card. The results obtained showed that compost use increased stem growth by 23%, this percentage was improved by 10% for greenhouse tests.

Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology, Sep 24, 2020

The current study focuses on the tolerance of a strain of Halobacterium salinarum isolated from S... more The current study focuses on the tolerance of a strain of Halobacterium salinarum isolated from Sfax solar saltern (Tunisia) towards cadmium (Cd), lead (Pb), nickel (Ni), zinc (Zn), and copper (Cu) by using agar dilution methods in complex and minimal media. The results showed the least inhibitory metals based on Minimum Inhibitory Concentrations (MICs) were lead (MIC = 4.5 mM), cadmium (MIC = 4 mM), and nickel (MIC = 2.5 mM) in complex medium. The MICs of these metals were more inhibitory (MIC \ 2 mM) in the other tested media. The archaeal strain revealed a high sensitivity for copper and zinc, with MICs below 0.5 mM for both metals. Growth kinetics in complex and minimal media showed the strain to be more sensitive to the metals in liquid media than in solid media. The growth kinetic assays indicated the presence of selected heavy metals resulted in a lower growth rate and lower total cell mass relative to the control. Despite that cadmium and lead are nonessential and have no nutrient value, they were the most tolerated metals by H. salinarum strain. In addition, pigment intensity in the strain was inhibited by the presence of the heavy metals relative to the control.

Springer eBooks, 2018

The MSW is the most worrying pollution source that must be managed by innovative treatment and re... more The MSW is the most worrying pollution source that must be managed by innovative treatment and recycling technologies. Its valorisation is required because of environmental legislation to limit its nuisance and preserve natural resources.

International Journal of Food Properties, Mar 1, 2012

This study deals with the chemical characterization of a medicinal and an aromatic plant of the T... more This study deals with the chemical characterization of a medicinal and an aromatic plant of the Tunisian flora: Allium roseum var. odoratissimum, and aimed to identify new bioactive natural compounds in its flower essential oil. These compounds were extracted by hydrodistillation and were analyzed by GC and GC/MS, using an apolar column. The most important compounds characterized were organo-sulphurous (46%),

Acta Horticulturae, 2010

This work is carried out on Allium roseum L., a North African endemic species, growing in the Sou... more This work is carried out on Allium roseum L., a North African endemic species, growing in the SouthEast of Tunisia and used as a vegetable, spice or herbal remedy in traditional medicine. Three protocols of extraction (Tris HCl buffer, phosphate buffer and sulphuric acid) were used in order to extract proteins from two different organs of this species (leaves and flowers). The antibacterial activities of different protein extracts were tested by disc diffusion, well diffusion and evaluated by the determination of minimum inhibitory concentration (CMI) and minimum bactericidal concentration (MBC). Results show that all extracts exhibited an antibacterial activity at different levels against strains reported as the causal agents of foodborne diseases. The determination of CMI and CMB relieves a very significant bactericidal activity to some strains such as C. albicans and E. coli. Results suggest the potential use of the plant as condiment and preservative in the food industry.

Acta Horticulturae, 1999

ABSTRACT

III International Symposium on Olive Growing, 1999

Waste Management, 2016

Municipal solid waste with high moisture content is the major hindrance in the field of waste to ... more Municipal solid waste with high moisture content is the major hindrance in the field of waste to energy conversion technologies and here comes the importance of biodrying process. Biodrying is a convective evaporation process, which utilizes the biological heat developed from the aerobic reactions of organic components. The numerous end use possibilities of the output are making the biodrying process versatile, which is possible by achieving the required moisture reduction, volume reduction and bulk density enhancement through the effective utilization of biological heat. In the present case study the detailed research and development of an innovative biodrying reactor has been carried out for the treatment of mixed municipal solid waste with high moisture content. A pilot scale biodrying reactor of capacity 565 cm 3 was designed and set up in the laboratory. The reactor dimensions consisted of an acrylic chamber of 60 cm diameter and 200 cm height, and it was enveloped by an insulation chamber. The insulation chamber was provided to minimise the heat losses through the side walls of the reactor. It simulates the actual condition in scaling up of the reactor, since in bigger scale reactors the heat losses through side walls will be negligible while comparing the volume to surface area ratio. The mixed municipal solid waste with initial moisture content of 61.25% was synthetically prepared in the laboratory and the reactor was fed with 109 kg of this substrate. Aerobic conditions were ensured inside the reactor chamber by providing the air at a constant rate of 40 litre per minute, and the direction of air flow was from the specially designed bottom air chamber to the reactor matrix top. The self heating inside reactor matrix was assumed in the range of 50-60°C during the design stage. Innovative biodrying reactor was found to be efficiently working with the temperature inside the reactor matrix rising to a peak value of 59°C by the fourth day of experiment (the peak observed at a height of 60 cm from the air supply). The process analyses results were promising with a reduction of 56.5% of volume, and an increase of 52% of bulk density of the substrate at the end of 33 days of biodrying. Also the weight of mixed MSW substrate has been reduced by 33.94% in 20 days of reaction and the average moisture reduction of the matrix was 20.81% (reduced from the initial value of 61.25% to final value of 48.5%). The moisture reduction would have been higher, if the condensation of evaporated water at the reactor matrix has been avoided. The non-homogeneous moisture reduction along the height of the reactor is evident and this needs further innovation. The leachate production has been completely eliminated in the innovative biodrying reactor and that is a major achievement in the field of municipal solid waste management technology.