11 research outputs found

    Antioxidant Capacities of Phenolic Compounds and Tocopherols from Tunisian Pomegranate (Punica granatum) Fruits

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    International audienceThis article aims to determine the phenolic, tocopherol contents, and antioxidant capacities from fruits (juices, peels, and seed oils) of 6 Tunisian pomegranate ecotypes. Total anthocyanins were determined by a differential pH method. Hydrolyzable tannins were determined with potassium iodate. The tocopherol (alpha-tocopherol, gamma-tocopherol, and delta-tocopherol) contents were, respectively, 165.77, 107.38, and 27.29 mg/100 g from dry seed. Four phenolic compounds were identified and quantified in pomegranate peel and pulp using the high-performance liquid chromatography/ultraviolet method: 2 hydroxybenzoic acids (gallic and ellagic acids) and 2 hydroxycinnamic acids (caffeic and p-coumaric acids). Juice, peel, and seed oil antioxidants were confirmed by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) methods. The highest values were recorded in peels with 25.63 mmol trolox equivalent/100 g and 22.08 mmol TE/100 g for FRAP and ORAC assay, respectively. Results showed that the antioxidant potency of pomegranate extracts was correlated with their phenolic compound content. In particular, the highest correlation was reported in peels. High correlations were also found between peel hydroxybenzoic acids and FRAP ORAC antioxidant capacities. Identified tocopherols seem to contribute in major part to the antioxidant activity of seed oil. The results implied that bioactive compounds from the peel might be potential resources for the development of antioxidant function dietary food

    Morphological and Physiological Changes Induced in the Date Palm Trees (Phoenix dactylifera) Exposed to Atmospheric Fluoride Pollution

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    Air quality bio-monitoring using plant leaves has been applied to assess the effects of atmospheric pollution. This study was conducted to evaluate the effects of fluoride (F) on date palm (Phoenix dactylifera) trees situated around a phosphate fertilizer-producing factory constituting a major source of pollution. Monthly observations on the southwest side of a phosphate fertilizer plant located in the coastal zone of the Gabès region have been assessed. This study was focused on the impact of F accumulation on the photosynthetic pigment content, cell membrane, and selected osmoprotectants (proline and soluble sugars) of the surveyed trees. Leaf samples were collected at various distances from the phosphate fertilizer factory (three sites at 0.5, 2.5, and 3.5 km and a control site at 35 km). Date palm trees accumulated significant amounts of F in leaves, with no visible lesions but showed a marked reduction in the photosynthetic pigment content, and damage to the cell membranes, as indicated by an increased malondialdehyde (MDA) content. The significant increases in the proline and soluble sugars contents in response to fluoride accumulation may be considered as defense mechanisms induced in response to fluoride stress. Based on photosynthetic pigment content, malondialdehyde (MDA), osmoprotectants levels and fluoride content, the date palm would be classified as a tolerant species

    Antifeedant and antigonadotropic effects of Ruta chalepensis methanolic extract against Locusta migratoria. Abdellaoui, K., Miladi, M., Ben Marzouk, I., Bahloul, N., Acheuk, F., Chaira, N., and Ben Halima-Kamel, M. (Tunisia / Algeria)

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    The migratory locust Locusta migratoria is one of the most important pests due to its extensive and serious damage to crops in large parts of Africa and Asia. To identify novel new environment friendly products for the management of the migratory locust, experiments were conducted to assess the effect of a methanolic extract of Ruta chalepensis (ME-Rc) on feeding activity and different reproductive phases of L. migratoria. The results showed that ME-Rc caused a significant decline in food intake and insect digestibility. The treatment applied to adult females caused a significant lengthening of the preoviposition period and a significant reduction in both fecundity and fertility. ME-Rc also affected growth and development of oocytes as evidenced by measurements of ovarian weight, length and volume of terminal oocytes and ovarian index. In addition, ME-Rc based-treatments led to disturbances in the incorporation of haemolymph metabolites (proteins and carbohydrates) in oocytes resulting in a significant decrease in their concentrations in ovaries

    Effect of thermal pretreatment at 70 degrees C for one hour (EU hygienization conditions) of various organic wastes on methane production under mesophilic anaerobic digestion

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    International audienceThe impact of hygienization as mild thermal pretreatment on the methane production of various organic wastes was investigated, including digestate issued from hydrolysis tank, thickened sludge from a municipal wastewater treatment plant (MWWTP sludge) and from a mixed domestic-industrial wastewater treatment plant (D-I WWTP sludge), sludge from a meat-processing plant (MP sludge), sieving rejection from a pork slaughterhouse, pork liver, cattle slurry, cattle scraping slurry and date seeds. They were thermally pretreated at 70 degrees C for one hour and subsequently put into AD digesters incubated at 37 degrees C for individual methane potential test. The modified Gompertz model was employed to evaluate the kinetic parameters of methane production curves (R-2 = 0.944-0.999). The results were compared with the untreated samples. Significant enhancement of methane potentials induced by thermal treatment (p < 0.05) was observed when it comes to the pork liver (+8.6%), the slaughterhouse sieving rejection (+11.1%), the thickened MWWTP sludge (+12.5%) and the digestate issued from hydrolysis tank (+18.0%). The maximum methane production rates of the 4 substrates mentioned above were increased by thermal pretreatment as well (from 13.5% to 64%, p < 0.05). The lag time of the methane production was shortened for the digestate from hydrolysis tank and the MWWTP sludge (by 48.6% and 62.2% respectively, p < 0.05). No significant enhancement was obtained for the cattle slurry, the cattle scraping slurry and the D-I WWTP sludge. Additionally, the maximum methane production rate and the methane potential were reduced by thermal pretreatment for the MP sludge and the date seeds respectively (p < 0.05). In this paper, possible mechanisms were discussed to explain the different methane production behaviors of substrates after the mild thermal pretreatment

    Quality attributes of Bearss Seedless lime (Citrus latifolia Tan) juice during storage.

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    The composition of three types of date juices, that differs by their couple of extraction and obtained from the rest of the sorting of cultivars Deglet Nour, were studied. The fruits were grown in Djerid region (Tozeur, Tunisia). Juices were characterised by yield, pH, soluble solids, organic acid, minerals content, individual carbohydrates, vitamin C, yeasts and moulds, coliforms and flora total aerobe contents. For the physicochemical parameters, only the J3 presents the best yields with content in citric acid of 2.13 g L-1, in phosphor of 0.083% (dry mater), in glucose 26.529 g L-1, in fructose 39.59 g L-1 and in sucrose 185.883 g L-1. For the bacteriological parameters, the results show that all prepared juices answer the microbiological requirements of hygiene well