Mimouni Yamina^{1, 2,}, Benaissa Atika^{1, 2}, Bedda Hafsia^{1, 3}

The objective of this research is to study the biological activity of date syrups of four cultivars: Kantichi, Tamesrit, Tantbouchet and Degla Beida from the South-East Algerian region. This study is carried out in the context of contributing to the enhancement of date palm heritage on the one hand and innovation of dietary products on the other hand, by a technological method. Diffusion of water soluble solids at two different concentration temperatures (65°C and 105°C) the targeted extraction technique in this practice. Qualitative characterization was positioned by the phytochemical screening. The quantitative analysis was carried out by measuring the phenolic compounds and condensed tannins. The evaluation of the antioxidant (anti-radical) activity was determined by the 1,1-Diphenyl-2-picryhydrazyl (DPPH) test. However, antibacterial activity was tested by the agar diffusion method against two bacterial strains (Escherichia coli, Staphylococcus aureus). The results obtained note the presence of flavonoids, tannins, coumarins, terpenoids, steroids, cardiotonic glycosides, saponosides and essential oils. The content of polyphénols varies between 194-712 mg equivalent of gallic acid/100 g of date syrup, that of condensed tannins varies between 34.7-265.34 mg of catechin equivalent/100g of date syrup. The concentration temperature of date syrups did not show a significant effect on the composition of phytochemicals. The evolution of the anti-free radical activity was perfectly clear according to the percentage inhibition curve (48.18%-97%). The inhibitory concentration (IC50) recorded was interesting, it oscillates between 0.04-0.47 mg/ml. The sensitivity of the strains to the syrups studied is manifested by significant zones of inhibition (10-12.5 mm) for concentrations (71-74° Brix). Overall, these elaborate syrups can be considered as an important source of natural antioxidant and / or functional food conferring appealing therapeutic properties.

Algeria, antioxidant activity, antibacterial activity, Date Syrup, phytochemicals