https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/74 2026-03-25T11:08:42Z https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/10413 Title: Effet de la méthode d’extraction aqueuse « macération et décoction » sur les différents composés et l'activité antioxydante des cladodes de l'Opuntia ficus-indica de la région de Ghardaïa Authors: HOUDJEDJE, Asma; BAAMMOUR CHIKH, Hanan Abstract: The young cladodes of Opuntia ficus-indica, consumed as a vegetable, are a valuable source of bioactive compounds and nutrients, and are the subject of our study on their antioxidant activity and nutritional value by analyzing primary and secondary metabolites as well as mineral content. Moisture content, phytochemical composition, mineral analysis, and quantitative determinations: primary metabolites, total polyphenols, total flavonoids, and antioxidant capacity were carried out following established experimental protocols on the dry matter and/or the two aqueous extracts prepared by maceration (Ex M) and decoction (Ex D). The results revealed the presence of flavonoids, polyphenols, alkaloids, free quinones, tannins, terpenes, and reducing compounds, while anthraquinones and saponins were absent. Nutritional analysis showed moisture, fiber, lipid, and ash contents of 92 ± 0,03%, 7,135 ± 0,3%, 1,763 %, and 26,69 ± 0,37%, respectively. Protein content was higher in the maceration extract (14,46 ± 0,01%) than in the decoction extract (10,02 ± 0,02%). Carbohydrates were 56.47% in the dry powder, 49.65% in Ex D, and 55.66% in Ex M. The energy value was low in fresh material (22 kcal/100 g), while the dry matter extracts were much more energetic (273–281 kcal/100 g DM). Total polyphenols and flavonoids were also more abundant in the maceration extract (53,53 ± 0,04 μg GAE/mg and 150,4 ± 0,03 μg RE/mg, respectively) than in the decoction extract. The maceration extract also contained higher levels of minerals, particularly Zn²⁺, Mg²⁺, P, Ca²⁺, and K⁺. Antioxidant activity assessed by the DPPH assay showed a strong IC₅₀, comparable to ascorbic acid, with 42,731 ± 0,46 mg/ml for the maceration extract and 49,643 ± 1,9 mg/ml for the decoction extract. Total antioxidant activity was 35,08 ± 0,06 μg AAE/mg for Ex M and 30,9 ± 0,00 μg AAE/mg for Ex D. According to our study, higher extraction temperatures have a negative impact on the levels of secondary metabolites and nutritional compounds in the aqueous extracts of the cladodes, consequently reducing their antioxidant activity. 2025-01-01T00:00:00Z https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/10408 Title: Valorisation agroalimentaire des dattes par la production de confiture : analyse technico-économique et optimisation du procédé de transformation Authors: DIAF, OMAR; OULAD YAHIA ILYES Abstract: This research aims to evaluate three varieties of dates (Ghars, Azerza, Timdjouhart) to select the most suitable for producing a healthy, high-quality date jam, by leveraging abundant raw material supply, developing new industrial production methods, and supporting the economy. A series of chemical and physical analyses were carried out, examining pH, electrical conductivity, water content, dry matter, ash content, sugar content (Brix), titratable acidity, along with microbiological analyses, to determine the variety best suited nutritionally and technologically. Results showed the pH ranged from 5.83 for Ghars, 6.18 for Azerza, and 5.97 for Timdjouhart, values close to neutrality, which are good for food preservation. Electrical conductivity was highest in Ghars (1208 µS/cm), followed by Timdjouhart (1177), and lowest in Azerza (1072), reflecting differences in mineral salt concentration. Regarding moisture, Timdjouhart had the lowest water content (35%) compared to Ghars (39%) and Azerza (38%), favoring higher sugar concentration and a firmer texture for the jam. Dry matter was highest in Timdjouhart (65%), then Azerza (62%), and Ghars (61%), an important advantage that reduces cooking time and preserves nutrients. Ash content was 4.5% in Ghars, versus only 3% in Azerza and Timdjouhart. Brix measurements, indicating soluble sugar concentration, showed Ghars and Timdjouhart reaching a high, identical rate (53.5%), significantly higher than Azerza (46%), offering natural sweetness and better preservation. Titratable acidity was highest in Timdjouhart (0.203), followed by Azerza (0.159), then Ghars (0.121), ensuring a good balance between sweetness and acidity and limiting microbial growth. In light of these results, Timdjouhart appears the most suitable variety for producing a healthy, high-quality date jam. It combines high dry matter content, which reduces cooking time, rich sugar content for natural sweetness and good preservation, and balanced acidity providing pleasant flavor and microbiological safety. These features make Timdjouhart the ideal choice for a nutritious jam with firm texture and harmonious taste. 2025-01-01T00:00:00Z https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/10401 Title: Etude de l’effet de stress hydrique sur les variétés de petit pois(pisumsativum L) Authors: Beldjoudi, Maroua; Bouregba, Maroua Abstract: An experimental study was conducted in 2025 at the Faculty of Natural, Life, and Earth Sciences in Ghardaïa, aiming to evaluate the effect of water deficit on two pea varieties (Kelvedon and Onward) through four irrigation levels (5%, 10%, 15%, 20% ). Statistical analyses revealed that water stress led to a significant decrease in the studied morphological and physiological parameters, including leaf number, stem and root length, as well as the fresh and dry weight of both aerial and underground parts, reflecting the direct negative impact of water shortage on pea growth and productivity. 2025-01-01T00:00:00Z https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/10400 Title: Caractérisation des sols agricoles dans une région aride : cas de Mansoura (Ghardaïa) Authors: ACHOUR, Tarek; MEKECHTI, Chouaib Abstract: This study was conducted in the Saharan commune of Mansoura, in the south of the province of Ghardaïa, with the aim of characterizing the physicochemical properties of agricultural soils and assessing the impact of cropping systems on their quality. Using 48 soil samples collected from various types of agricultural land (cereals, olive trees, palm trees) and uncultivated control plots, several parameters were analyzed, including pH, electrical conductivity (EC), calcium carbonate (CaCO₃) content, organic matter (OM), and texture. The results revealed high spatial variability between the study sites. Soil pH was generally neutral to slightly alkaline (7.185 to 7.795), which is characteristic of arid environments, although there were differences between plots depending on agricultural practices. Electrical conductivity revealed moderate to high salinity levels (0.2885 dS/m to 8.595 dS/m), particularly in olive groves (8.595 dS/m), suggesting salt accumulation due to insufficiently controlled irrigation. CaCO₃ content (3.92% to 17.54%) varies considerably, reflecting a local geological influence, with higher levels in some areas with calcareous substrates. As for organic matter (2.13% to 3.10%), it is generally low, reflecting the low biological productivity of arid soils, but a few plots show a significant improvement where sustainable practices (organic amendments, crop rotations) are implemented. Texturally, the majority of soils have a sandy to sandy- clayey texture, which reduces their water and nutrient retention capacity, and poses a major constraint to the sustainability of agricultural systems. Overall, the results confirm that soil quality in this region is strongly influenced by agricultural practices and highlight the urgent need to adopt sustainable management strategies to preserve soil fertility, optimize water use, and improve the resilience of agroecosystems to the extreme climatic conditions specific to arid zones. 2024-01-01T00:00:00Z