Sidi Mohamed Ounane

Effects of Physicochemical Characteristics and Lipid Distribution in Algerian Durum Wheat Semolinas on the Technological Quality of Couscous

ABSTRACT Semolinas milled from 18 Algerian durum wheat cultivars cropped over a two-year period (1999-2000) were used for making couscous. This study was designed to determine the impact of lipid components of durum wheat semolina on the quality of the couscous end product. Lipids were extracted from semolina by various techniques and classified as free or bound lipids, polar or apolar lipids, and glycolipids or phospholipids. An analysis of the overall results clearly revealed that the cooking quality of couscous made from different durum wheat semolinas was partially dependent on the semolina free lipid content and composition. We have shown that this is mainly a varietal characteristic (53.4%). The surface state of the couscous, i.e., caking index (r = -0.48) and cooking loss (r = -0.54), thus depends on the apolar lipid content. Polar lipids, and especially glycolipids, affect couscous texture in terms of firmness (r = 0.57 and r = 0.63, respectively). Polar bound lipids also contribute to couscous sw...

Discrimination against 15N among recombinant inbred lines of Phaseolus vulgaris L. contrasting in phosphorus use efficiency for nitrogen fixation

Although isotopic discrimination processes during nitrogen (N) transformations influence the outcome of (15)N based quantification of N2 fixation in legumes, little attention has been given to the effects of genotypic variability and environmental constraints such as phosphorus (P) deficiency, on discrimination against (15)N during N2 fixation. In this study, six Phaseolus vulgaris recombinant inbred lines (RILs), i.e. RILs 115, 104, 34 (P deficiency tolerant) and 147, 83, 70 (P deficiency sensitive), were inoculated with Rhizobium tropici CIAT899, and hydroaeroponically grown with P-sufficient (250 μmol P plant(-1) week(-1)) versus P-deficient (75 μmol P plant(-1) week(-1)) supply. Two harvests were done at 15 (before nodule functioning) and 42 (flowering stage) days after transplanting. Nodulation, plant biomass, P and N contents, and the ratios of (15)N over total N content ((15)N/Nt) for shoots, roots and nodules were determined. The results showed lower (15)N/Nt in shoots than in roots, both being much lower than in nodules. P deficiency caused a larger decrease in (15)N/Nt in shoots (-0.18%) than in nodules (-0.11%) for all of the genotypes, and the decrease in shoots was greatest for RILs 34 (-0.33%) and 104 (-0.25%). Nodule (15)N/Nt was significantly related to both the quantity of N2 fixed (R(2)=0.96***) and the P content of nodules (R(2)=0.66*). We conclude that the discrimination against (15)N in the legume N2-fixing symbiosis of common bean with R. tropici CIAT899 is affected by P nutrition and plant genotype, and that the (15)N/Nt in nodules may be used to screen for genotypic variation in P use efficiency for N2 fixation.

Seed Oil from Ten Algerian Peanut Landraces for Edible Use and Biodiesel Production

As a result of a recent ad hoc prospection of the Algerian territory, a collection of peanut (groundnut; Arachis hypogaea L.) landraces was established, covering a remarkable array of diversity in terms of morphological and physiological features, as well as of adaptation to local bioclimatic conditions. In the present work, the oils extracted from the seeds of these landraces were evaluated in terms of edible properties and suitability for biodiesel production. As for edible use, a low free acidity (ranging from 0.62 to 1.21%) and a high oleic acid content (44.61-50.94%) were common features, although a poor stability to oxidation [high peroxide values, high spectrophotometric indices, and low % of inhibition in the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH)· test] was observed in a few cases. As for biodiesel production, low values of acidity [1.23-2.40 mg KOH (g oil)(-1)], low iodine values [90.70-101.54 g I2 (g oil)(-1)], high cetane numbers (56.95-58.88) and high calorific values (higher heating value 37.34-39.27 MJ kg(-1)) were measured. Edible properties and suitability for biodiesel production were discussed with respect to the German standard DIN 51605 for rapeseed oil and to the EN 14214 standard, respectively. One way ANOVA and Hierarchical Cluster Analysis showed significant differences among the oils from the Algerian peanut landraces.

Evaluation of pesticide residues in fruits and vegetables from Algeria

ABSTRACT A total of 160 samples of 13 types of fresh fruits and vegetables from domestic production and import were analysed to detect the presence of pesticide residues. Analysis was performed by multi-residual extraction followed by gas chromatography–mass spectrometry. In 42.5% of the tested samples, no residues were found and 12.5% of samples contained pesticide residues above maximum residue limits. Risk assessment for long-term exposure was done for all pesticides detected in this study. Except chlorpyrifos and lambda-cyhalothrin, exposure to pesticides from vegetables and fruits was below 1% of the acceptable daily intake. Short-term exposure assessment revealed that in seven pesticide/commodity combinations, including three pesticides (chlorpyrifos, deltamethrin and lambda-cyhalothrin), the acute reference dose had been exceeded.

REPONSES MORPHO-PHYSIOLOGIQUES ET BIOCHIMIQUES DE LA SYMBIOSE RHIZOBIA-ARACHIDE AU STRESS HYDRIQUE

Despite the level of resistance sizable developed by peanut (Arachis hypogaea L.) production in the dry ecosystems is affected by periods of water deficit occurring during the growth cycle. The purpose of this work was to highlight the responses to water deficit low, moderate and severe of five peanut populations of local and foreign origin were inoculated by three rhizobiens strains, to identify criteria for selecting symbiotic interactions better adapted to drought. Water stress was imposed by withholding water at the floral initiation stage. The mechanisms studied focused on the morpho-physiological aspects (height of the stem, leaf area, content of proline and soluble sugar, relative water content, leaf water potential, stomatal resistance and leaf temperature), biochemical aspects (fixation and assimilation of nitrogen) and agronomical aspects (yield and its components). During the stress treatment, relative water content and leaf water potential decreased and stomatal resistance, leaf temperature increased in all symbiotic interactions. Water Réponses morpho-physiologiques et biochimiques de la symbiose rhizobia-archide au stress hydrique ISSN 2170-1318 4 Algerian journal of arid environment vol. 3, n° 1, Juin 2013: 3-14 stress also increased sugar and proline concentrations and decreased the assimilation and fixation of nitrogen. All these effects of water impact negatively on the vegetative growth and on yield and its components. The symbiotic interactions studied behave differently depending on the severity of water stress. However, symbiotic interactions SA3-BER, SA3-OUM, SA3-TON, SA3-TIM, SA1BER, SA1-TON and SA1-OUM proved the most tolerant to different degrees of water stress applied. As against the symbiotic interactions SA2-TIM and SA2-NIG showed a significant sensitivity over the lack of water. The behavior of other symbiotic interactions varied depending on the severity of stress applied. Moreover, the genetic variability of plant material in relation to water stress does not appear related to the geographical origin of populations of peanut, but rather to their phenology and morphology. This study could serve to define criteria for resistance to drought used in breeding.