الفهرس 
Evaluation of the antioxidant and antimicrobial activities of different parts of Moringa plantOnly 14 pages are availabe for public view
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Abstract
Moringa oleifera tree is a multipurpose tree, each part of this plant has its own uses. Leaves are used to combat malnutrition in developing countries by adding it to their meals. Seeds also used to purify water supplies by precipitate impurities and decrease its microbial load. Roots are used to treat several maladies such as kidney pain and constipation. So, the aim of this study is to determine the proximate composition of different parts (leaves, seeds and roots) in two different forms (fresh and dried), comparing between the efficacy of different solvents (aqueous and ethanolic) to extract bioactive compounds (phenols and flavonoids), measuring antioxidant activity of all extracts using DPPH and FRAP methods, identification extracted compounds using HPLC, measure the antioxidant and antimicrobial activities for each extract. The best form and the most effective extract were used after that to supplement two popular products with part and its extract and evaluate the ability of additive to extend shelf life of these new products by retard its oxidation and decrease inhibit microbial growth. The results obtained from this study were very promising. To begin with proximate composition, seeds contained higher amount of protein (37.91%) while leaves and roots contained 29.22% and 13.28%, respectively. Also, seeds contained high amount of oil 42.13% followed by leaves 8.96% then roots 1.16%. on the other hand, dried leaves contained 15.21% minerals higher than that found in seeds and roots (3.49 and 4.22%, respectively). Moringa oleifera roots are a good source for dietary fiber it contained 40.55% crude fiber followed by leaves which contained 24.62% then seeds (13.73%). Secondly, ethanol solvent was more effective than water to extract phenolic compounds from leaves and roots while water was more efficient than ethanol to extract phenolic compounds from seeds. Also, leaves in both forms (fresh and dried) using both solvents (water and ethanol) contained total phenolics higher than that found in roots and seeds. Dried leaves ethanolic contained the highest amount of total phenolic content (20.46 mg gallic acid equivalent/1 g extract) followed by fresh leaves aqueous extract 12.28 mg GAE/ 1 g extract, dried leaves ethanolic extract 11.18 mg GAE/ 1 g extract and 5.58 mg GAE/ 1 g extract for dried leaves aqueous extract. Seeds aqueous extract contained 3.35 mg GAE/ 1 g extract followed by aqueous extract (2.01 mg GAE/ gm extract). Dried roots using both extractants (water and ethanol) showed higher amount of total phenols (3.96 and 5.72 mg GAE/ g extract, respectively) than that found in fresh roots extracts (aqueous 1.19 mg GAE/ g extract and ethanolic 1.15 mg GAE/ g extract). Ethanolic extract of both forms (fresh and dried) leaves and roots contained higher amount of flavonoids than that found in aqueous extract of the same parts. Also, ethanolic extract of dried roots contained (2.04 Ru/g) higher than (0.76 Ru/g) that found in fresh root ethanolic extract and fresh and dried roots aqueous extracts (0.79 Ru/g for each), while seeds aqueous extract contained (1.06 RU/g) higher than (0.90 RU/g) ethanolic extract. from the obtained data leaves contain high amount of phenols and flavonoids that seeds and roots. Thirdly, the antioxidant activity of dried leaves ethanolic extract showed higher scavenging activity against DPPH than that found by ascorbic acid and other extracts. The scavenging activity of dried leaves ethanolic extract at high concentration was almost similar to that obtained from using BHA as synthetic antioxidant agent. Moreover, ethanolic extract of dried leaves showed the highest reducing power (78.79) followed by MDL aqueous extract (43.49), MDR ethanolic extract (41.90), MFL (36.66), MFR aqueous extract, MDL aqueous extract (29.40), MDL aqueous extract (25.84), seeds ethanolic extract (11.14), seeds aqueous extract (9.33) and MFR ethanolic
extract (8.01). Finally, to evaluate the antimicrobial effect of different parts extracts, all extracts tested against 9 bacterial strains and 6 fungal strain. Aqueous extract of seeds showed antibacterial activity greater than that resulted from testing aqueous extract of fresh and dried leaves although, fresh leaves aqueous extract of fresh leaves had more antibacterial activity than dried leaves. While, aqueous extract of fresh and dried roots had no antibacterial activity against tested bacterial strains. On the other hand, dried leaves ethanolic extract showed powerful antibacterial activity against tested strains than that obtained from using rest extracts. However, strains Clostridium botulinum ATCC 3584 and Staphylococcus aureus NCTC 10784 could not be inhibited using all extract. Seeds aqueous extract was the only extract that showed antifungal activity against tested fungal strains but dried leaves ethanolic extract showed inhibition zone diameter greater than that resulted from using seeds aqueous extract and also showed lower inhibitory concentration than that resulted from using seeds aqueous extract. from all obtained data, dried leaves and its ethanolic extract were the best choice to study their addition to food products as antimicrobial and antioxidant agents in comparison with positive control (containing BHA) and negative control (without addition). 1% and 0.5% of dried leaves powder and its ethanolic extract were separately added to beef burger and evaluated their ability to extend shelf life under refrigerated storage at 4ºC. The results revealed that the addition of both dried leaves powder and dried leaves ethanolic extract showed ability to extend shelf life of product compared with negative and positive control. The addition of extract decreased TBA value, TVC, psychrophilic count and Enterobacteriaceae count without affecting sensory evaluation of samples. Also, fortification of croissant using 1% MDL and 1% MDLE were able to decrease yeast and mold count and retard lipid oxidation parameters with no significance difference and without affecting sensory parameters comparing with negative and positive controls.