| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 691.96 KB | Adobe PDF |
Advisor(s)
Abstract(s)
The present work determines the chemical and thermal characteristics as well as the phytochemical
and antioxidant potential of the polar extractives of the Picea abies bark from an
industrial mill, their wood and bark components and also different bark fractions obtained by
mechanical fractionation (fine B1, Φ<0.180 mm, medium B3, 0.450 < Φ<0.850 mm and
coarse B6, 2 < Φ<10 mm). The aim is to increase the knowledge on the Picea abies bark to
better determine possible uses other than burning for energy production and to test an initial
size reduction process to achieve fractions with different characteristics. Compared to
wood, bark presented similar lignin (27%), higher mineral (3.9% vs 0.4%) and extractives
(20.3% vs 3.8%) and lower polysaccharides (48% vs 71%) contents. Regarding bark fractions
the fines showed higher ash (6.3%), extractives (25%) and lignin (29%) than the
coarse fraction (3.9%, 19% and 25% respectively). Polysaccharide contents increased with
particle size of the bark fractions (38% vs 52% for B1 and B6) but showed the same relative
composition. The phytochemical profile of ethanol and water extracts presented higher contents
for bark than wood of total phenols (2x higher), flavonoids (3x higher) and tannins (4-
10x higher) with an increasing tendency with particle size. Bark antioxidant activity was
higher than that of wood for ferric-reducing antioxidant power (FRAP, 10 vs 6 mmolFe2+/gExt
for the ethanol extract) and free radical scavenging activity (DPPH, 6 vs 18 mg/L IC50 for
the ethanol extract) methods. The different bark fractions antioxidant activity was very similar.
Bark thermal properties showed a much lower volatiles to fixed carbon ratio (V/FC) than
wood (3.1 vs 5.2) although the same higher heating value (20.3 MJ/kg). The fractions were
quite similar. Bark presented chemical features that point to their possible upgrade, whether
by taking advantage of the high extractives with bioactive compounds or the production
potential for hemicellulose-derived oligomers with possible use in nutraceutical and pharmaceutical
industries
Description
Research Article
Keywords
Picea abies industrial bark chemical composition thermal properties polar extracts activity
Pedagogical Context
Citation
Neiva DM, Araujo S, Gominho J, Carneiro AdC, Pereira H (2018) An integrated characterization of Picea abies industrial bark regarding chemical composition, thermal properties and polar extracts activity. PLoS ONE 13 (11): e0208270
Publisher
David A. Lightfoot