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    Comparison of antioxidant activities of juice, peel, and seed of pomegranate (Punica granatum L.) and inter-relationships with total phenolic, Tannin, anthocyanin, and flavonoid contents
    (Korean Society Food Science & Technology-Kosfost, 2012) Orak, Hakime Hulya; Yagar, Hulya; Isbilir, Sebnem Selen
    In this study, the antioxidant activities of juice, peel, and seed parts of pomegranate were investigated by using DPPH scavenging activity, beta-carotene bleaching method, reducing power, and metal chelating activity. Sample of pomegranates which are named Punica granatum L. cv. Hicaznar, genotype 19-121, genotype 17-67, and genotype 19-66 obtained from BATEM (West Mediterranean Agricultural Research Institute) in Anlalya. The EC50 values of DPPH scavenging activities in peel extracts (PE) had 23.4-fold higher than the juice extracts (JE), and the seed extracts (SE) had 2.3-fold higher than JE. The reducing power in peel extracts was found to be 4.7-fold higher than SE and 10.5-fold higher than the JE. The highest metal chelating capacity (37.22%) was determined in peel, while the lowest (7.151%) in seed. Generally, in peel, the total polyphenol, flavonoid, tannin contents, and in juice, the total polyphenol, anthocyanin, tannin contents, and acidity significantly affected to antioxidant activities.
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    DETERMINATION OF ANTIOXIDANT ACTIVITIES OF STRAWBERRY TREE (Arbutus unedo L.) FLOWERS AND FRUITS AT DIFFERENT RIPENING STAGES
    (Wydawnictwo Akad Rolniczej W Lublinie, 2012) Isbilir, Sebnem Selen; Orak, Hakime Hulya; Yagar, Hulya; Ekinci, Neslihan
    In this study, the antioxidant activities of Strawberry tree (Arbutus unedo L.) flowers at flowering period and fruits during ripening period were investigated, along with some ripening characteristics such as color, reducing sugar and acidity. Antioxidant activity characteristics were investigated using by the methods of DPPH (1,1-Diphenyl-2-picryl-hydrazyl) scavenging activity, beta-carotene bleaching, reducing power, metal chelating capacity, superoxide anion scavenging and hydrogen peroxide scavenging activity in water, ethanol and methanol extracts. The total phenolic content of flowers in water extracts was found to be 232.38 +/- 7.19 mg GAE . g(-1) extract, and the DPPH activity was 81.3 +/- 0.49% at 50 mu g.ml(-1) concentration. In the ripening stages, the fully red fruits were determined higher antioxidant capacity than green and yellow fruits, except H2O2 scavenging activity which was highest in green fruit. In correlation study, the highest relationship was found between total phenolic content with reducing power (r(2) = 0.987**, P < 0.01), while the lowest with H2O2 scavenging activity (r(2) = 0.519*, P < 0.05).
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    Determination of antioxidant properties of lyophilized olive leaf water extracts obtained from 21 different cultivars
    (Korean Society Food Science & Technology-Kosfost, 2012) Orak, Hakime Hulya; Isbilir, Sebnem Selen; Yagar, Hulya
    The objective of this study was to compare the antioxidant activities of lyophilized olive leaf water extracts (OLWExtracts) from 21 different olive tree cultivars. The highest total phenolic content (102.69 +/- 1.63 mu g GAE/mg extract) was found in cultivar 'Esek Zeytini' and the lowest content (78.52 +/- 2.18 mu g GAE/mg extract) was in 'Uslu'. The highest total flavonoid content (12.47 +/- 0.12 mu g QE/mg extract) obtained from 'Frantoio'. According to EC50 values, 'Domat' have the highest DPPH scavenging activity (EC50 =59 mu g/mL), reducing power (EC50 =180 mu g/mL), and superoxide radical scavenging capacity (EC50=44 mu g/mL). While, 'Ascolana' showed the highest metal chelating capacity (EC50=163 mu g/mL), 'Memecik' showed the highest hydrogen peroxide (H2O2) scavenging capacity. Research results exhibited that OLWExtracts are comparable to synthetic antioxidants. The correlation study showed that while total phenolic content correlated with DPPH scavenging activity and reducing power (p < 0.01), total flavonoid content correlated with metal chelating and superoxide radical scavenging capacity (p < 0.05).
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    Evaluation of Antioxidant and Antimicrobial Potential of Strawberry Tree (Arbutus Unedo L.) Leaf
    (Korean Society Food Science & Technology-Kosfost, 2011) Orak, Hakime Hulya; Yagar, Hulya; Isbilir, Sebnem Selen; Demirci, Ahmet Sukru; Gumus, Tuncay; Ekinci, Neslihan
    In present study, antioxidant and antimicrobial activities of strawberry tree (Arbutus unedo L.) leaves were investigated. Antioxidant activity was determined by methods of DPPH scavenging, beta-carotene bleaching, reducing power, metal chelating, superoxide anion scavenging, and hydrogen peroxide scavenging activity. Total phenolic content were determined to be 197.16 +/- 1.43 mg GAE/g extract in aqueous extract. The EC50 value of methanolic extracts was found to be 0.423 mg/mL. The extracts of leaves showed nearly 1/4 metal chelating capacity of standard EDTA, high reducing power, superoxide anion scavenging, and hydrogen peroxide scavenging activities. While the strawberry tree leaves exhibited antibacterial activity against Staphylococcus aureus, there was no inhibitory effect against Escherichia coli and Salmonella enteritidis. The strawberry tree leaves exhibited antifungal effect against 2 aflatoxigenic molds namely Aspergillus parasiticus NRRL 2999 and NRRL 465. These results suggest that the strawberry tree leaves may be used as an antioxidant source for pharmaceutical application, nutraceutical and functional food industries.