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Tytuł:
Wpływ warunków parzenia na zawartość antyoksydantow w naparach różnych rodzajów herbat
Influence of brewing conditions on antioxidant content in different kinds of tea infusions
Autorzy:
Kurleto, K.
Kurowski, G.
Laskowska, B.
Malinowska, M.
Sikora, E.
Vogt, O.
Powiązania:
https://bibliotekanauki.pl/articles/172172.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
herbata
antyoksydanty
całkowita aktywność antyoksydacyjna
tea
antioxidants
total antioxidant capacity
Opis:
Tea has been consumed all over the World for over two thousand years and now it is the most popular caffeine-containing beverage. Its worldwide consumption is second only to water [1–3]. The tea is not only important because of its popularity but also due to its beneficial influence on human health [4]. The biological benefits of tea are due to their flavanol content [5–13]. Tea flavanols are a group of natural polyphenols (Fig. 2). Therapeutic effects of tea have been extensively examined in many in vitro and in vivo tests. It was confirmed that tea leaves ingredients have antibacterial, antifungial, antiviral properties, they also prevent cell mutations and they inhibit progress of heart diseases. Moreover, tea can stimulate neural system and regulate its functions [14–20]. All this activities are mostly due to antioxidant ability of tea polyphenols (Fig. 4). Tea production process can be run in different ways and this affects of the tea taste, aroma, colour and antioxidants content. According to fermentation degree, different tea kinds can be obtained (Fig. 1). During the manufacturing process of black and oolong teas, tea leaves are crushed to allow polyphenol oxidase to catalyze the oxidation and polymerization of catechins to polymers called theaflavins and thearubigins (Fig. 3) [21–23]. Green or white teas are obtained through shorter fermentation, so the catechin concentration remains higher. Tea is prepared by infusing tea leaves in hot water. Brewing process conditions like temperature, brewing time, pH, besides other factors has a significant influence on polyphenols content [24-32]. Many studies have determined total flavonoids content and antioxidant activity according to different tea type and brewing conditions, tea plantation type or fermentation process. The amount of total polyphenol was determined using the F-C method, catechins, caffeine and polyphenolic acids were analysed using High Performance Liquid Chromatography with reversed phase. Obtained results let compare how different production and brewing processes affect the tea quality [33–56].
Źródło:
Wiadomości Chemiczne; 2013, 67, 11-12; 1129-1147
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Właściwości antyoksydacyjne, antybakteryjne i przeciwgrzybicze związków kompleksowych miedzi(II)
Antioxidant, antibacterial and antifungal properties of complex compounds of copper(II)
Autorzy:
Piotrowska, A.
Drzeżdżon, J.
Jacewicz, D.
Chmurzyński, L.
Powiązania:
https://bibliotekanauki.pl/articles/171722.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
związki kompleksowe
miedź(II)
antyoksydanty
aktywność antybakteryjna
aktywność przeciwgrzybicza
copper(II) complexes
antioxidants
antibacterial activity
antifungal activity
Opis:
Since late 1930s copper has been recognized as an essential trace metal in living organisms. Copper(II) cation plays the role as a coordination center not only in the single-nuclear complexes, but also in the multinuclear coordination compounds with a particular emphasis on the polymers as ligands. The selected complex compounds of copper(II) with ligands which are organic and inorganic species have been characterized taking into account their physico-chemical properties. In addition, the complex compounds containing ligands such as Schiff ’s bases, hydrocarbons, organic bases, and also polycarboxylic anions: oxydiacetate, thiodiacetate, iminodiacetate and dipicolinate have been described considering their role in the biological systems. Nowadays tested coordination compounds of copper(II) have interesting antibacterial activities against bacteria strains that are antagonistic to the human. The antibacterial activity of copper(II) complex is stronger than some of the known antibacterial substances e.g. ciprofloxacin. In addition, copper(II) complex compounds exhibit a 64-fold greater antimicrobial properties than copper(II) chloride. Moreover, these compounds have antifungal and antioxidant properties. The activities of antibacterial, antifungal, and antioxidant complex compounds of copper( II) have been compared to the reactivities of these compounds with complexes used as reference substances, e.g. L-ascorbic acid, in the assay using nitrotetrazolium blue.
Źródło:
Wiadomości Chemiczne; 2017, 71, 3-4; 219-240
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
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