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PubMed | Institute Of Lolivier Of Sousse and University of Monastir
Type: Journal Article | Journal: Pakistan journal of biological sciences : PJBS | Year: 2014

The olive tree is generally grown under rain-fed conditions. However, since the yield response to irrigation is great, even with low amounts of water, there is increasing interest in irrigated agriculture. The main goal of this study was, therefore, to investigate the effect of irrigation regimes on olive (Olea europaea L., cv. Koroneiki) obtained from an intensively-managed orchard in a semi-arid area with a Mediterranean climate in Tunisia. Different irrigation treatments 50% ETc, 75% ETc and 100% ETc were applied to the olive orchard. Accordingly, the effects of three irrigation regimes on volatile compounds, fatty acid composition and biological activities of Koroneiki cultivar were studied. The total profile of the volatile constituents of all samples revealed the predominance of 3-ethenylpyridine (from 14.9-19.6%), phenylethyl alcool (from 7.8-19.2%) and benzaldehyde (from 9.0 to 13.8%). During watering level treatments studied, the major fatty acids were oleic, palmitic and linoleic. Antioxidant activity of the fresh fruit volatiles cultivated at a watering level of 100% ETc was higher than that obtained under 50 and 75% Etc. The results of antifungal activity showed that the fruits volatiles of the three irrigation treatments had varying degrees of growth inhibition against the microorganisms tested.


Dabbou S.,University of Monastir | Brahmi F.,University of Monastir | Selvaggini R.,University of Perugia | Chehab H.,Institute Of Lolivier Of Sousse | And 3 more authors.
International Journal of Food Science and Technology | Year: 2011

Nowadays, a significant increase in intensively and irrigated managed olive orchards has occurred in Tunisia in the hope to increase the olive production. Aromatic profile with sensory analysis were considered in virgin olive oils from Arbequina, Coratina and Koroneiki cultivars grown intensively under three irrigation treatments (T1, T2 and T3 equivalent to 50%, 75% and 100% ETc.). Results showed that the aromatic quality depends first on the irrigation level applied and second on the cultivar. From sensory analysis, hay-like and greasy were the principal off-flavour detected. As the amount of supplied water increased, volatiles showed different behaviours depending on cultivar and the most important changes occurred in the release of the three alcohols ((E)-2-penten-1-ol, 1-hexanol, (E)-2-hexen-1-ol and phenylethyl alcohol) and hexanal. The most effective by irrigation regimes in separating cultivars were (E)-2-hexenal, (Z)-2-penten-1-ol, (E)-2-hexen-1-ol, fruity, bitter and pungent sensory descriptors. In conclusion, the data obtained herein proved the heavy influence of the cultivar in comparison with irrigation regimes. © 2011 The Authors. International Journal of Food Science and Technology © 2011 Institute of Food Science and Technology.


Dabbou S.,University of Monastir | Chehab H.,Institute Of Lolivier Of Sousse | Brahmi F.,University of Monastir | Taticchi A.,University of Perugia | And 2 more authors.
International Journal of Food Science and Technology | Year: 2011

The impact of different irrigation regimes based on two ripeness index, on the quantity and quality of virgin olive oil from the introduced olive cultivar Olea europaea L. Koroneiki grown at a high-density olive orchard in northern Tunisia, was assessed. Olive trees were subjected to three treatments (T1, T2 and T3) that received a seasonal water amount equivalent to 50%, 75% and 100% of the estimated local evaporative demand by a drip irrigation system and olives were collected in two different ripeness index. The olive oil content decreased when the water applied was increased but rose during ripening. The quality indexes and fatty acid composition were less affected by the irrigation schedule but most significantly by the maturity of olives. Moreover, phenol contents increased according to fruit ripening whereas no clear cut differences or consistent effects were observed by irrigation. α-tocopherol decreased slightly in the oils as ripening progressed while insignificant differences between the irrigation treatments studied were obtained. Consequently, a restitution of 75% of crop evapotranspiration (ETc.) was sufficient to achieve good minor compounds; however, higher water volumes (100% ETc.) gave little additional α-tocopherol and phenols increases. © 2011 The Authors. International Journal of Food Science and Technology.


Mechri B.,University of Monastir | Mechri B.,Institute Of Lolivier Of Sousse | Chehab H.,Institute Of Lolivier Of Sousse | Attia F.,Equipe Recherches Agronomiques | And 3 more authors.
European Journal of Soil Biology | Year: 2010

The aim of this work was to study the effects of spreading olive mill wastewater (OMW) on the soil surface of an olive grove on the soil microbial communities. Analyses of ester-linked fatty acid methyl esters (EL-FAME) were used to assess variations in the soil microbial community structure following land spreading of OMW. Our data provide evidence that agronomic application of OMW has important effects on soil microbial community. Bacteria were relatively more reduced by these treatments than fungi and actinomycetes as revealed by an increased index of fungal/bacterial FAME and actinomycetes/bacterial FAME. Specific FAME markers indicated a significant reduction in the Gram-positive bacteria. However, the relative proportion of the Gram-negative bacteria was not significantly different after agronomic application of OMW. The ratios of cyclopropyl/monoenoic precursors decreased and the total monounsaturated/total saturated fatty acids increased in the OMW amended soils, suggesting that the microbes inhabiting the control soil are more carbon limited than the OMW amended soils. The changes in the FAME pattern of the soil organisms possibly were related (i) to an altered substrate quantity, that is the availability of substrates after the treatments, (ii) the complex nature of OMW which also contains high molecular-mass recalcitrant polyphenols. © 2010 Elsevier Masson SAS.


Mechri B.,University of Monastir | Attia F.,Equipe Recherches Agronomiques | Tekaya M.,University of Monastir | Cheheb H.,Institute Of Lolivier Of Sousse | Hammami M.,University of Monastir
Soil Biology and Biochemistry | Year: 2014

The objectives of this study were to determine the long-term effects of agronomic application of olive mill wastewaters (OMW) with rock phosphate (RP) in a field of olive trees on the soil microbial community structures. Ester-linked fatty acid methyl ester (EL-FAME) profiles were used for characterizing the numerically dominant portion of soil microbial communities. EL-FAME analysis showed significant shifts of specific groups of fatty acids after application of OMW with RP. In particular, the FAME 10Me18:0 indicative of actinomycetes increased and the FAME 18:1ω9 and 18:2ω6 commonly found in fungi decreased. The soil microbial cells reacted to the addition of OWM and RP with an increase in the percentage of cy17:0 and cy19:0 cyclopropane fatty acids. Other changes in FAME composition included the increase of saturated/unsaturated ratio. It seems that alterations of fatty acid composition, after agronomic application of OMW and RP, are responsible for the substantial maintenance of cell membrane integrity, physiological functions and growth. © 2013 Elsevier Ltd.


Tekaya M.,University of Monastir | Mechri B.,University of Monastir | Bchir A.,Institute Of Lolivier Of Sousse | Attia F.,Equipe Recherches Agronomiques | And 3 more authors.
Journal of the Science of Food and Agriculture | Year: 2013

Background: This work was conducted to determine the effects of two nutrient-based fertilisers on the general physicochemical characteristics (including free fatty acid content, peroxide value and UV spectrophotometric characteristics), fatty acid profile, total phenols, o-diphenols and phytosterol composition of olive oil. Foliar applications were carried out in two successive years and included four treatments: TC (control, without foliar nutrition), T1 (rich in nitrogen, applied at the start of vegetation, 10 days later and 20 days later), T2 (rich in boron, magnesium, sulfur and manganese, applied at the beginning of flowering and 10 days later) and T3 (T1 + T2). At the end of the experiment (after 2 years), oils were extracted and analysed. Results: No effect was found on either general physicochemical characteristics or fatty acid composition. Foliar fertilisation caused a significant decrease in both polyphenol and o-diphenol contents. Total sterol content was unaffected by foliar fertilisation. However, the phytosterol composition of the oil, particularly its β-sitosterol level, was markedly improved after foliar nutrient application. Principal component analysis of the phytosterol composition showed discrimination between the control oil and the oils from T1, T2 and T3 treatments. Conclusion: The results of this study extend the current knowledge of such cross-talk between plant nutrition and quality of oil. © 2012 Society of Chemical Industry.


Dabbou S.,University of Monastir | Chehab H.,Institute Of Lolivier Of Sousse | Faten B.,University of Monastir | Esposto S.,University of Perugia | And 5 more authors.
Agricultural Water Management | Year: 2010

This study investigated the effect of irrigation amount on the concentration of phenolic compounds in olive (Olea europaea L., cv. Arbequina) oil obtained from an intensively-managed orchard in a semi-arid area with a Mediterranean climate in Tunisia. Different irrigation treatments 50% Etc, 75% Etc and 100% Etc were applied to the olive orchard. Oil quality, evaluated using the parameters established to determine the quality level of virgin olive oils (acidity, K232, K270 and peroxide index) was slightly affected by irrigation. However, results showed that irrigation positively affected both fruit and oil quality. In fact, the least irrigation regime (T1), showed a significantly higher content of oleic acid (70.08%), whereas olive oils from more irrigated trees (T2 and T3) had higher contents of palmitic acid (11.64% and 13.14%, respectively) and lower of linoleic acid (approximately 12.7%). However, content of phenolic compounds (hydrophilic and lypophilic), in the oils extracted, strongly differed. In fact, different irrigation regimes applied not only affected the total amount of phenols which were proportional to irrigation (193.2 and 271.87 mg kg-1 for T1 and T3, respectively) except for T2 but also their HPLC profiles. Contrarily to phenols, insignificant differences were observed in the concentration of α-tocopherol between the irrigation treatments studied. © 2010 Elsevier B.V. All rights reserved.


Mechri B.,University of Monastir | Mechri B.,Institute Of Lolivier Of Sousse | Cheheb H.,Institute Of Lolivier Of Sousse | Boussadia O.,Institute Of Lolivier Of Sousse | And 4 more authors.
Environmental and Experimental Botany | Year: 2011

Olive mill wastewater (OMW) management is a serious environmental issue for the Mediterranean area where there is the most production of olive oil. OMW contains a high organic load, substantial amounts of plant nutrients but also several compounds with recognized toxicity towards living organisms. Moreover, OMW may represent a low cost source of water. We studied the influence of irrigation with OMW (amounts applied: 30, 60, 100 and 150m3h-1) in a field of olive trees on root colonization, photosynthesis, chlorophyll fluorescence, leaf nutrient concentration and soluble carbohydrate. The soil fatty acid methyl ester (FAME) 16:1ω5 was used to quantify biomass of arbuscular mycorrhizal (AM) fungi and the root FAME 16:1ω5 analysis was used as index for the development of colonization in the roots. Agronomic application of OMW decreased significantly the abundance of the soil FAME 16:1ω5 and the root FAME 16:1ω5 in the soil amended with 60, 100 and 150m3ha-1 OMW. Decreased root FAME 16:1ω5 due to OMW amendment was associated with a significant reduction of tissue nutrient concentrations in the olive trees. The highest application of OMW to the soil reduced significantly the olive trees uptake of N, P, K, Ca, Mg, Fe, Cu, Mn and Zn. Land spreading of OMW increased concentration of soluble carbohydrate in the olive leaves, mostly due to decreased sink demand for carbon by the root. In the olive trees amended with 150m3ha-1 OMW, net CO2 uptake rate (A), quantum yield of photosystem II electron transport (ΦPSII), maximal photochemical efficiency of photosystem II (Fv/Fm), photochemical quenching (qp) and the electron transport rate (ETR) were significantly depressed, whereas non-photochemical quenching (NPQ) was found to increase. Taken with data from experiments in field conditions, our results suggest that agronomic application of OMW alters the functioning of arbuscular mycorrhizas and can even disrupt the relationship between AM fungi and olive trees. © 2010 Elsevier B.V.


Mechri B.,University of Monastir | Tekaya M.,University of Monastir | Cheheb H.,Institute Of Lolivier Of Sousse | Hammami M.,University of Monastir
Journal of Chromatographic Science | Year: 2015

This study reports a method for the analysis of mannitol, sorbitol and myo-inositol in olive tree roots and rhizospheric soil with gas chromatography. The analytical method consists of extraction with a mixture of dichloromethane:methanol (2:1, v/v) for soil samples and a mixture of ethanol:water (80:20) for root samples, silylation using pyridine, hexamethyldisilazane (HMDS) and trimethylchlorosilane (TMCS). The recovery of mannitol sorbitol and myo-inositol (for extraction and analysis in dichloromethane:methanol and ethanol:water) was acceptable and ranged from 100.3 to 114.7%. The time of analysis was <24 min. Among identified polyols extracted from rhizosphere and roots of olive plants, mannitol was the major compound. A marked increase in mannitol content occurred in rhizosphere and roots of water-stressed plants, suggesting a much broader role of mannitol in stress response based on its ability to act as a compatible solute. © The Author 2015. Published by Oxford University Press. All rights reserved.


PubMed | Institute Of Lolivier Of Sousse and University of Monastir
Type: Journal Article | Journal: Journal of chromatographic science | Year: 2015

This study reports a method for the analysis of mannitol, sorbitol and myo-inositol in olive tree roots and rhizospheric soil with gas chromatography. The analytical method consists of extraction with a mixture of dichloromethane:methanol (2:1, v/v) for soil samples and a mixture of ethanol:water (80:20) for root samples, silylation using pyridine, hexamethyldisilazane (HMDS) and trimethylchlorosilane (TMCS). The recovery of mannitol sorbitol and myo-inositol (for extraction and analysis in dichloromethane:methanol and ethanol:water) was acceptable and ranged from 100.3 to 114.7%. The time of analysis was <24 min. Among identified polyols extracted from rhizosphere and roots of olive plants, mannitol was the major compound. A marked increase in mannitol content occurred in rhizosphere and roots of water-stressed plants, suggesting a much broader role of mannitol in stress response based on its ability to act as a compatible solute.

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