https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/72 Faculté des Sciences de la Nature et de la Vie et des Sciences de la Terre 2026-04-12T22:43:14Z https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/10417 Contribution à l’étude des effets biocides des extraits végétaux d’espèces spontanées sur des bioagresseurs des cultures en milieu saharien ARABA, Fatna In the context of enhancing and valorizing natural resources, methanolic extracts from two parts of three spontaneous plant species collected in the Algerian Sahara Cotula cinerea Del. (inflorescences and leaves), Peganum harmala L. (seeds and leaves), and Pergularia tomentosa L. (seeds and leaves) were tested for their antifungal activity. Extraction yields ranged from 11% to 24%. The highest yield was obtained from the leaf extract of C. cinerea (24%), followed by the leaf extract of P. harmala (22%) and P. tomentosa (21%). The seed extract of P. harmala showed a yield of 20.1%, while the inflorescence extract of C. cinerea yielded 18%. The lowest extraction yield (11%) was obtained from P. tomentosa seeds. Phytochemical screening of the hydro-methanolic extracts obtained by reflux extraction revealed a rich and diverse composition of secondary metabolites. Tannins were present in all crude extracts except the leaf extract of P. harmala Alkaloids were characteristic of C. cinerea and P. harmala, but absent in P. tomentosa. Flavonoids were detected in all extracts except those of P. harmala. Reducing compounds, free quinones, saponins, and steroids were completely absent in C. cinerea, while P. harmala lacked flavonoids and free quinones, and P. tomentosa was devoid of coumarins and alkaloids. Terpenoids were found in all crude extracts except the seed extract of P. harmala. In vitro evaluation of antifungal activity against the mycelial growth of two pathogenic fungi Mauginiella scaettae Cav. and Fusarium oxysporum f.sp. albedinis using a direct contact test, revealed variable inhibitory effects among the tested extracts. Methanolic extracts of C. cinerea and P. harmala exhibited significant antifungal activity at all tested concentrations against both fungal species, with markedly reduced mycelial growth compared to the control. Notably, the seed extract of P. harmala at 20% concentration completely inhibited the mycelial growth of M. scaettae Cav. For F. oxysporum f.sp. albedinis, inhibition rates of 61.29%, 72.89%, and 83.94% were observed at 40%, 50%, and pure extract concentrations, respectively. Abstract The seed extract of P. tomentosa showed moderate antifungal activity against M. scaettae at lower concentrations, while the inflorescence and leaf extracts of C. cinerea at 40% concentration inhibited F. oxysporum f.sp. albedinis growth by more than 50%. These findings suggest that it would be of particular interest to further investigate the potential synergistic effects of aqueous extracts from the studied plants. 2025-01-01T00:00:00Z https://dspace.univ-ghardaia.edu.dz/xmlui/handle/123456789/10413 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 HOUDJEDJE, Asma; BAAMMOUR CHIKH, Hanan 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 Valorisation agroalimentaire des dattes par la production de confiture : analyse technico-économique et optimisation du procédé de transformation DIAF, OMAR; OULAD YAHIA ILYES 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 Etude de l’effet de stress hydrique sur les variétés de petit pois(pisumsativum L) Beldjoudi, Maroua; Bouregba, Maroua 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