Yazar "Ozkok, Asli" seçeneğine göre listele

Listeleniyor 1 - 5 / 5
  • Küçük Resim Yok
    Öğe
    Bee collected pollen as a value-added product rich in bioactive compounds and unsaturated fatty acids: A comparative study from Turkey and Romania
    (Elsevier, 2021) Margaoan, Rodica; Ozkok, Asli; Keskin, Saban; Mayda, Nazli; Urcan, Adriana Cristina; Cornea-Cipcigan, Mihaiela
    The aim of this study was to determine the botanical origin, phenolics, flavonoids and fatty acids content, antioxidant and antimicrobial properties, of 18 bee collected pollen (BP) samples from Turkey and Romania. Five plant families with predominant pollens (>45%) were found in the Turkish samples, and only three in the Romanian samples. The phenolic content, varied between 16.40 and 41.17 mg GAE/g and the flavonoids content varied between 2.39 and 7.17 mg QE/g. The highest value of DPPH was 2.93 mmol Trolox/g and 9.64 mmol Trolox/g for the TEAC, whereas the IC50 value of alpha-Amylase inhibition was 8.10 mg/mL. We also verified that the presence of the methanolic extract of BP differentially affected the growth of Gram-positive and Gram-negative bacteria under study, strongly depending on the microorganism and the botanical origin of the BP samples used. The fatty acids contents were closely correlated with the above-mentioned parameters especially with the botanical origin and antibacterial activity. Our findings suggest that BP is a rich source of unsaturated fatty acids and bioactive compounds, which can be considered a value-added product. Furthermore, the differences in Turkish and Romanian BP chemical composition is also shown based on their antimicrobial and alpha-amylase inhibitory activities.
  • Küçük Resim Yok
    Öğe
    Honey: Determination of volatile compounds, antioxidant and antibacterial activities
    (Czech Academy Agricultural Sciences, 2021) Karlidag, Semiramis; Keskin, Merve; Bayram, Sinan; Mayda, Nazli; Ozkok, Asli
    Honey is an important functional food for human health and nutrition that is collected by honey bees and stored in the honeycombs. In this study, total phenolic content, antioxidant activity and volatile compounds of 13 different honey samples collected from various districts of Malatya province were investigated. As a result of this study, it was determined that the total phenolic content varied between 8.50 mg GAE 100 g(-1) and 73.90 mg GAE 100 g(-1) and it was observed that the honey samples were rich in aldehydes, aliphatic acid and esters, alcohols, hydrocarbons, carboxylic acid esters, ketones, terpenes, fatty acids and esters. In addition, the antibacterial effects of honey samples were determined against 18 different pathogenic bacteria using agar well diffusion (AWD) method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). In AWD assay, it was recorded that inhibition zone diameters varied between 9 mm and 14 mm and honey samples were found to have a partial inhibitory effect against selected target pathogens.
  • Küçük Resim Yok
    Öğe
    Organic acids and their derivatives: minor components of bee pollen, bee bread, royal jelly and bee venom
    (Springer, 2022) Celik, Saffet; Gercek, Yusuf Can; Ozkok, Asli; Bayram, Nesrin Ecem
    This study aimed to determine the organic acid profiles of bee products such as royal jelly, bee venom, bee pollen and bee bread, as well as to verify the method employed in the study. For this purpose, royal jelly, bee venom, bee pollen and bee bread samples were obtained from different locations, and 55 individual organic acids were determined using the liquid chromatography technique coupled with tandem mass spectrometry (LC-MS/MS), and method verification was carried out. Moreover, principal component and hierarchical cluster analyses were performed to compare the organic acid content of bee products and evaluate the overall variation. According to the results, the order of the total organic acid profiles was determined as bee venom (4141 mg/kg-6260 mg/kg) > bee bread (736-990 mg/kg) > bee pollen (837-1503 mg/kg) > royal jelly (192-1947 mg/kg). Although citric acid (423-41,519 mg/kg) was dominantly detected in samples among the organic acids screened. It is thought that the results obtained will contribute to scientific studies carried out to determine the authenticity of bee products and their standardization.
  • Küçük Resim Yok
    Öğe
    Phenolic and free amino acid profiles of bee bread and bee pollen with the same botanical origin - similarities and differences
    (Elsevier, 2021) Bayram, Nesrin Ecem; Gercek, Yusuf Can; Celik, Saffet; Mayda, Nazli; Kostic, Aleksandar Z.; Dramicanin, Aleksandra M.; Ozkok, Asli
    In this study, the chemical profile of bee pollen (BP) and bee bread (BB) samples collected from the same beehive were analyzed by LC-MS/MS (liquid chromatography technique coupled with tandem mass spectrometry), providing the identification of 23 phenolic compounds and 42 free amino acids (FAAs). Rutin was the phenolic compound with the highest rate of occurrence in both BP and BB samples. However, concentrations of protocatechuic acid, 2,5-dihydroxybenzoic acid and kaempferol compounds were significantly higher in BB samples than in BP samples from the same hive probably as result of microbial activity and glycosides degradation. The obtained data revealed that the phenolic profiles of the samples differ not only by the type of a product but also by region. Among FAAs proline was the predominant compound in all the analyzed BP and BB samples followed by L-asparagine (BP samples) and L-aspartic acid (BP and BB samples). A high content of proline can be used as a parameter of sample freshness. Also, Principal Component Analysis (PCA) and Cluster analysis proved the possibility of using phlorizin as a chemotaxonomic marker for Rosaceae (Malus or Prunus genus) pollen presence in BP1 sample. In addition, amino acid profile had higher impact on BP and BB sample differentiation due to lower FAAs content in BB samples probably caused by microbial activity. To the best of our knowledge, this study is the first to compare the individual phenolic compounds and free amino acids of bee pollen and bee bread samples with the same botanical origin (predominantly originated from plants belonging to the following families: Asteraceae, Fabaceae, Plantaginaceae and Rosaceae). (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.
  • Küçük Resim Yok
    Öğe
    Total Bioactive Compounds and Antimicrobial Capacities of Bee Pollen with Different Botanical Origins
    (Univ Agricultural Sciences & Veterinary Medicine Cluj-Napoca, 2021) Ozkok, Asli; Koru, Ozgur; Bedir, Orhan; Cetinkaya, Serdar; Celemli, Omur Gencay; Ozenirler, Cigdem; Mayda, Nazli
    Bee pollen has many therapeutic properties with its rich chemical content. Especially the phenolic substances in the structure of bee pollen are very effective in showing the bioactive compounds. Thanks to these properties, bee pollen is used as a food supplement. It is known that these features are influenced by many factors such as climate, geography and plant origin. Therefore, it is important to determine the botanical origins of bee products. In this study, botanical origins and total bioactive compounds were determined at the seven bee pollen samples collected from different regions of Turkey. Also, antimicrobial activity of the seven bee pollen samples against seven different bacterial pathogens and one fungal agent using broth microdilution method were studied. Asteraceae, Fabaceae, Cistaceae, Papaveraceae families were found as a dominant in the regions by botanical origins examination. Total phenolic values were found between 24.77 +/- 288.824 mg GAE/g and 51.61 +/- 727.14 mg GAE/g. Total flavonoid content was 1.36 +/- 0.015 mg QE/g and 2.40 +/- 0.077 mg QE/g. The antimicrobial results showed that each of the tested bee pollen samples inhibited the growth of the gram-positive and gramnegative bacteria at the different levels while they did not have a complete inhibitory effect on the fungi.