Effet de l’ombrage sur la culture sous serre du vétiver (Chrysopogon zizanioides L.)

A. BEN ROMDHANE¹,

S. BOUKEF²,

CH. KARMOUS¹,

S. SLIM¹,

H. KHMIRI³,

M. HAMMAMI¹

¹ Higher School of Agriculture of Matter, 7030 Tabarka Road, Matter, Tunisia.

² Chott-Mariem Higher Agricultural Institute, PB 47, 4042 Chott-Mariem, Sousse, Tunisia

³ Sylvo Pastoral Development Office of the North-West (ODESYPANO), Avenue of the Environment 9000 Béja, Tunisia.

Abstract – Effects of shading on growth and development of vetiver (Chrysopogon zizanioides L.) have been investigated under greenhouse. The results showed that the growth of vetiver is significantly influenced by shading. Indeed, the shading have been induced an increasement 50% number of tillers per plant, 86% plant growth, 14% length of roots, 8% number of leaves and 50% dry matter content compared to control. Moreover, this plant has a very important nutritional value (0.8 UFL). Thus, this new introduced species could constitute an additional forage resource for Tunisia

Keywords: Chrysopogon zizanioides, Forage, vetiver, shading.

Résumé – Le présent travail vise l’étude de la culture du vétiver (Chrysopogon zizanioides L.) sous l'effet de l’ombrage. Les résultats ont permis de mettre en évidence que la croissance du vétiver est significativement influencée par l’ombrage. En effet, sous ombrière, on a enregistré une augmentation moyenne de 50% du nombre de talles, de 86% de la longueur de la partie aérienne, de14% de celle racinaire, de 8% du nombre de feuilles et de 50% de la matière sèche par rapport aux plants cultivés sans ombrage. En outre, cette plante possède une valeur nutritionnelle très importante (0.8 UFL). Ainsi, cette nouvelle espèce introduite pourra constituer une ressource fourragère supplémentaire pour la Tunisie

Mots clés : Chrysopogon zizanioides, Fourrage, vétiver, ombrage.

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S. KHARCHOUFI^1*,

M. AHMED ABBAS MAHMOUD^2,3,4,

S. LOUPASSAKI⁵,

M. HAMDI¹

¹ Laboratory of Microbial Ecology and Technology, National Institute of Applied Sciences and Technology (INSAT), University of Carthage, Centre Urbain Nord, 2 Boulevard de la Terre, B.P. 676, 1080 Tunis, Tunisia

² Department of Chemistry and Pharmacy, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestrasse 9, 91054 Erlangen, Germany

³ Departement Sensory Analytics, Fraunhofer Institute for Process Engineering and packaging (IVV), Giggenhauser Str. 35, 85354 Freising, Germany

⁴ Agricultural biochemistry departement, faculty of agriculture, Ain Shams University, PO Box 68, Hadayek Shobra, 11241 Cairo, Egypt

⁵ Department of Food Quality and Chemistry of Natural Products, Mediterranean Agronomic Institute of Chania, Centre International de Hautes Etudes Agronomiques Méditerranéennes, Chania, PO Box 85, 73100 Chania, Crete, Greece

Abstract – Greek yoghurt is a highly nutritious fermented product characterized by its higher protein, low sodium and low carbohydrate contents, and has gained immense popularity compared to traditional yoghurt. It has a unique semi-solid texture due to manufacturing process. In this study, Greek yoghurt was fortified with pomegranate juice (PJ) and arils (PA) to investigate its thick-matrix effect on the availability of phenolics and dietary antioxidant during 18 days of storage at 4˚C and to get indications about the best treatment that could sustain antioxidants during the storage period. PJ or PA in 20 % were mixed with cultured and dessert Greek yoghurts (CPJ, CPA, DPJ, DPA respectively). The total phenolics (TPC), using Folin-Ciocalteu, and antioxidant activity, using DPPH, FRAP, and luminal-induced chemiluminescence, were tested over four periods of storage (1; 6; 12; 18 days). Organoleptic quality was evaluated as well.
The obtained results indicated that both PJ and PA enhance the TPC and antioxidant activity of both yoghurts, and the cultured yoghurt appeared to be a better matrix to preserve pomegranate’s bioactive molecules.

Keywords: Greek yoghurt; pomegranate; TPC; antioxidant activities; sensorial quality

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Incidences du paturage sur la degradation et sur la regeneration de la suberaie de kroumirie (nord-ouest de la tunisie)

N. BOUSSAIDI¹,

L. REBAI²

¹ Institut Sylvo-Pastoral de Tabarka (Laboratoire des Ressources Sylvo-Pastorales)

² Direction Générale des Forêts (Tunisie)

Abstract – Forest grazing steel, a Mediterranean tradition in North Africa (Karmouni, 2005). Due to overgrazing, forest suffers and regeneration is often absent. State Forest area occupies approximately 900,000 ha, with 368,000 covered by natural forests in good condition. The rest is covered by substituted vegetation in destroyed forests by deforestation, overgrazing and charring. The interactions between humans and the environment are many in Kroumiria with a limited potential development. This situation translates a fragile balance, born on a confrontation between two misfortunes:
- The particularly vulnerable submitted one is subject to a very strong pressure which causes degradation,
- The one of a disadvantaged population, whose livelihoods have become more limited with the rural increasing densities, and who is obliged to over-exploit environment and resources to survive (Buju S., 1997).
Indeed, the study area, part of the Kroumiria, is composed of three forest series (Ain Draham X, Tegma I and tegma II) with a total area of 10156 ha 2954 ha is occupied by Cork oak with a varied livestock composed by goats, sheep in forest grazing where they spend the most part of the year in the Cork oak forest by affecting accentuated overgrazing disrupting the hole ecosystem

Keywords: Cork oak forest, golf course forest, overgrazing, degraded, vegetation, Kroumirie, man, livestock.

Résumé - Le parcours forestier est une tradition méditerranéenne encore vivace dans les pays du Maghreb (Karmouni, 2005). En raison du surpâturage, la forêt souffre et la régénération y est souvent absente. Le domaine forestier de 1'Etat occupe environ 900.000 ha dont une superficie de 368.000 ha est couverte de forêts naturelles en bon état. Le reste est couvert d'une végétation se substituant aux forêts détruites par les défrichements, surpâturage et la carbonisation. Les interactions entre l'Homme et le milieu, sont nombreuses en Kroumirie dont les potentialités de développement sont limitées. Cette situation se traduit par un équilibre fragile, né de la confrontation entre deux précarités :
- Celle d'un milieu particulièrement vulnérable, soumis à une pression très forte qui entraîne une dégradation,
- Celle d'une population défavorisée, dont les moyens de subsistance sont devenus de plus en plus limités avec l'augmentation des densités rurales, et qui est obligée de surexploiter milieu et ressources pour survivre (Buju S., 1997).
En effet, la zone étudiée, faisant partie de la Kroumirie, est composée de trois séries forestières (Ain Draham X, Tegma I et tegma II) ayant une superficie totale de 10156 ha dont 2954 ha occupés par le Chêne-liège avec un cheptel varié s'articulant surtout sur les caprins et les ovins où ils passent presque toute l'année dans la subéraie en l'affectant de surpâturage accentué perturbant tout l'écosystème

Mots clés : subéraie, parcours forestier, surpâturage, végétation dégradée, Kroumirie, l'Homme, cheptel.

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I. FELFOUL*,

M. BORCHANI,

O. SAMET-BALI,

H. ATTIA,

M.A. AYADI

Laboratoire Valorisation, Analyses et Sécurité des Aliments, Ecole Nationale d’Ingénieurs de Sfax, Route de Soukra, 3038 Sfax, Tunisie

Abstract – The present study aims to investigate the addition effect of ginger powder (Zingiber officinalis) in bovine milk used for yogurt processing by determining the physico-chemical, the rheological and the sensory attributes after 24-hour storage. The total phenolic content and the antioxidant activity were evaluated during 21 days of cold storage at 4 °C for control and fortified yogurt samples with 1% ginger powder. The supplementation of bovine milk with ginger powder at concentration ranging from 0.5 to 2.5% (w/v), accelerated the rate of pH reduction, increased the total solids contents, reduced the syneresis rate, increased the apparent viscosity and improved the textural properties of yogurt samples. Fortified yogurt sample with 1% ginger powder showed higher values of total phenolics content, DPPH scavenging activity, reducing power and metal chelating assay during storage period compared to control samples. Furthermore, the antioxidant activity for 1% ginger yogurt increased significantly over storage period.

Keywords: Ginger powder, yogurt, antioxidant activity, total phenolics, syneresis

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Activité antioxydante et composition biochimique des bulbes frais et des feuilles fraiches de l’ail sauvage Allium ursinum

D. SAHNOUN,

W. MEGDICHE KSOURI,

I. YOUNES, M. HAMMAMI,

I. BETTAIEB, M.SAADA,

K. MKADMINI,

R. KSOURI,

R. BEJI SERAIRI*

Laboratory of Medicinal and Aromatic Plants Biotechnology Center of Borj Cedria, Hammam-Lif 2050, Tunis El Manar University, Tunisia.

Abstract – Allium ursinum commonly called wild garlic or bear’s garlic is a medicinal species commonly recommended in traditional medicine for its therapeutic properties as well as common garlic. To the best of our knowledge, phytochemical investigations and antioxidant capacities of this plant remain unclear. This work assessed the phenolic composition of fresh bulbs and leaves of A. ursinum and evaluated their antiradical capacity according to the extraction method. Extraction was realized by two methods: infusion and decoction. Phenolic composition was determined by quantitative analysis of total phenolics, flavonoids and condensed tannins. Antioxidant activity was evaluated through the use of synthetic radical DPPH. Results showed that extraction method and organ influence biochemical composition and antioxidant activity. It has been observed that leaves were significantly richer in total polyphenols, flavonoids and condensed tannins than bulbs. Decoction gave the richest extract of polyphenols and flavonoids. However, infusion gave the richest extract of condensed tannins. The higher percentage of DPPH inhibition (66.61%) belong to the extract of fresh bulbs obtained by infusion. Because of the odor of the bulbs extract, we thought to analyze extracts with Gas Chromatography coupled to Mass Spectrometry (GC/MS). Our data showed that volatile composition of extracts is variable depending on the extraction method. Volatile fraction obtained by infusion was mainly composed of disulfide methyl propyl (46.45%) and disulfide dipropyl (53.55%). While decoction gave three compounds which are 1-limonene (41.74%), delta.-cyclogeraniolene (36.70%) and 3-butyl-1-cyclohexane (21.56%). Our findings showed that both organ and extraction method significantly affected biochemical composition and antioxidant activity.

Keywords: Allium, polyphenols, GC-MS, antioxidant activity, DPPH, infusion, decoction

Résumé -Allium ursinum, appelé ail sauvage ou ail des ours, est une espèce médicinale recommandée en médecine traditionnelle pour ses propriétés thérapeutiques comme l’ail commun. Au meilleur de nos connaissances, les investigations phytochimiques et les capacités antioxydantes de cette plante restent non claires. Ce travail s’intéresse à la composition phénolique des bulbes frais et des feuilles fraiches d’Allium ursinum et évalue leurs capacités anti radicalaire en fonction de la méthode d’extraction. L’extraction a été réalisée par deux méthodes: l’infusion et la décoction. La composition phénolique a été déterminée par l’analyse quantitative des polyphénols totaux, flavonoïdes et tannins condensés. Les résultats obtenus montrent que la méthode d’extraction et l’organe influencent la composition biochimique et l’activité antioxydante. Il a été observé que les feuilles sont significativement plus riches en polyphénols totaux, flavonoïdes et tannins condensés que les bulbes. La décoction donne l’extrait le plus riche en polyphénols et flavonoïdes. Tandis que, l’infusion donne l’extrait le plus riche en tannins condensés. Le pourcentage de l’inhibition de DPPH le plus élevé (66.1 %) appartient à l’extrait des bulbes frais obtenu par infusion. Grâce à l’odeur de l’extrait des bulbes, nous avons pensé à analyser les extraits par la Chromatographie Gazeuse couplée à la Spectrométrie de Masse (GC/MS). Nos données montrent que la composition volatile des extraits est variable dépendant de la méthode d’extraction. La fraction volatile obtenue par infusion était principalement composée de disulfide methyle propyle (46.45%) et disulfide dipropyle (53.55%). Par contre, la décoction donne trois composés qui sont: 1-limonène (41.74%), delta.-cyclogeraniolène (36.70%) and 3-butyle-1-cyclohexane (21.56%). Nos résultats montrent que, l’organe et la méthode d’extraction affectent significativement la composition biochimique et l’activité antioxydante

Mots clés : Allium, Polyphénols, GCMS, activité antioxydante, DPPH, infusion, décoction.

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S. KHERIJI^1*,

I. RABEH²,

M. EL CAFSI²,

N. BOURIGA¹,

W. MASMOUDI¹,

MS. ROMDHANE³

¹ Higher institute of Peach and the Fish farming of Bizerte

² Reaserch Unit of Physiology and Aquatic Environment, University of Tunis El Manar

³ Research Unit for Ecosystems and Aquatic Resources (UR03AGRO1), National Agronomic Institute of Tunisia (INAT)

Abstract – An experiment was conducted to investigate the effect of soybean meal enrichment on growth performance, protein content, fatty acid composition of Mugil cephalus fry (Mean initial body weight, 0.420 ± 0.06 g). Three experimental diets, based on 2 ingredients (an extruded diet (ED) and the soybean meal (SBM)), were formulated: control diet: D_c (50% ED and 50% SBM), D₂₅ (75% of ED and 25% of SBM) and D75 (25% of ED and 75% of SBM). The results showed that high level of soybean meal affects negatively growth of Mugil cephalus fry specially at the second half of the experience. The protein content increase significantly, during experience, only for FD_c. We can then replace fish meal based diet with soybean meal until 50% for providing them with a good protein rate. Concerning lipid, major fatty acid is the 16:1. We find that unlike FD₇₅, FD₂₅ and FD_c total body fatty acids decreases significantly according to time. However, more the food is rich in soybean meal, more fatty acids, and particularly EPA and DHA levels decrease significantly at the beginning of the experiment. It seems that their proportion in diets D₂₅, D_c and D₇₅ is insufficient for providing a good fish growth.

Keywords: diet; fatty acids; growth; Mugil cephalus; protein; soybean meal.

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