Yazar "Demirci, A. S." seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF WHITE, GREEN AND BLACK TEA EXTRACTS
    (Akademiai Kiado Zrt, 2013) Orak, H. H.; Yagar, H.; Isbilir, S. S.; Demirci, A. S.; Gumus, T.
    In the present study, the antioxidant and antimicrobial activities of three tea (Camellia sinensis) types (white tea WT, green tea - GT, and black tea - BT) were compared and the relationships between total phenolic, tannin and flavonoid contents were determined. Regardless of the assays used, the highest total phenolic content (313.3 +/- 1.41 mu g GAE/mg extract), total flavonoid (16.98 +/- 0.27 mu g QE/mg extract) and total tannin content (266.79 +/- 2.59 mu g TAE/mg extract) were determined in green tea extract, which also demonstrated the highest antioxidant capacity. Black tea extract showed the lowest phenolic content and antioxidant capacity. The EC50 value of DPPH scavenging activity was in the order of: ascorbic acid >GT>BHA>WT>BT>BHT. While the tea extracts exhibited antibacterial activity against Staphylococcus aureus, no inhibitory effects were observed against Escherichia coli and Salmonella enteritidis. All extracts exhibited antifungal activity against two aflatoxigenic moulds Aspergillus parasiticus NRRL 2999 and NRRL 465. The antibacterial activity of tea extracts decreased in the following order: GT>WT>BT DPPH scavenging activity strongly correlated with total phenolic content, reducing power, antimicrobial activity against S. aureus, A. parasiticus NRRL 2999, A. parasiticus NRRL 465 (P<0.05). These data suggest that green tea extract is more effective than white and black tea extracts as a potential source of natural antioxidants.
  • Küçük Resim Yok
    Öğe
    Phytosterols as Functional Food Ingredients
    (Univ Namik Kemal, 2006) Tasan, M.; Bilgin, B.; Gecgel, U.; Demirci, A. S.
    Phytosterols are defined as plant sterols and plant stanols. Phytosterols lower total and LDL blood cholesterol by preventing cholesterol absorption from the intestine, so they have been known as blood cholesterol-lowering agents for over the last half century. Phytosterols are naturally found in vegetable products, principally oils. Dietary phytosterol intakes are normally range from 170 to 360 mg/day with variations depending on food culture and major food sources. Recent studies have shown that maximum cholesterol-lowering benefits are achieved at doses of 2-3 g per day. Therefore today's use implies the need for enriched functional food products, which give enough phytosterols intake.