CHARACTERIZATION OF BARK RICH-IN-TANNINS EXTRACTS FROM DECIDUOUS TREES WITH EMPHASIS ON THEIR ANTIOXIDANT ACTIVITY

Baltic Polymer Symposium 2015

材料科学;化学

Janceva, S.^1 ; Dizhbite, T.^1 ; Vevere, L.^1 ; Arshanitsa, A.^1 ; Telysheva, G.^1 ; Dzenis, M.^2

Latvian State Institute of Wood Chemistry, Dzerbenes Street 27, Riga

LV-1006, Latvia^1

Riga Technical University, Faculty of Material Science and Applied Chemistry, Institute of Polymer Materials, P. Valdena Street 3, Riga

LV-1048, Latvia^2

关键词: Anti-oxidant activities;    Antioxidant efficiencies;    Condensed tannins;    Deciduous trees;    Oligomeric proanthocyanidins;    Polyurethane films;    Radical scavenging capacities;    Thermo-oxidative;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/111/1/012013/pdf
DOI  :  10.1088/1757-899X/111/1/012013

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The barks of deciduous trees spread over a wide area of Northern Europe, were sequentially extracted using solvents of increasing polarity. The highest yields of hydrophilic extractives were found for ash tree and goat willow (23.6% and 23.8%, respectively). The highest total contents of polyphenols were found for black alder and goat willow bark (0.18 GAE•g-1and 0.12 GAE•g-1, respectively). Hydrophilic extract from the both grey and black alder barks contained high amount (up to 7% on bark dry mass) of condensed tannins (CT) or oligomeric proanthocyanidins (OPC). In tests with free radicals (ABTS•+, DPPH•), the high radical scavenging capacities of the hydrophilic extracts enriched with OPC were demonstrated. The antioxidant efficiency of the hydrophilic extracts and purified OPC from alder barks was tested by their influence on thermo-oxidative destruction of model polyurethane (PU) films. The hydrophilic extracts enriched with tannins have good potential as a technical antioxidant for polyurethanes, with the most prominent activity for the hydrophilic extract from black alder and goat willow bark.