A1 Journal article (refereed)
Behaviour of Extractives in Norway Spruce (Picea abies) Bark during Pile Storage (2022)

Halmemies, E. S., Alén, R., Hellström, J., Läspä, O., Nurmi, J., Hujala, M., & Brännström, H. E. (2022). Behaviour of Extractives in Norway Spruce (Picea abies) Bark during Pile Storage. Molecules, 27(4), Article 1186. https://doi.org/10.3390/molecules27041186

JYU authors or editors

Publication details

All authors or editors: Halmemies, Eelis S.; Alén, Raimo; Hellström, Jarkko; Läspä, Otto; Nurmi, Juha; Hujala, Maija; Brännström, Hanna E.

Journal or series: Molecules

eISSN: 1420-3049

Publication year: 2022

Publication date: 10/02/2022

Volume: 27

Issue number: 4

Article number: 1186

Publisher: MDPI AG

Publication country: Switzerland

Publication language: English

DOI: https://doi.org/10.3390/molecules27041186

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/80217


The current practices regarding the procurement chain of forest industry sidestreams, such as conifer bark, do not always lead to optimal conditions for preserving individual chemical compounds. This study investigates the standard way of storing bark in large piles in an open area. We mainly focus on the degradation of the most essential hydrophilic and hydrophobic extractives and carbohydrates. First, two large 450 m3 piles of bark from Norway spruce (Picea abies) were formed, one of which was covered with snow. The degradation of the bark extractives was monitored for 24 weeks. Samples were taken from the middle, side and top of the pile. Each sample was extracted at 120 °C with both n-hexane and water, and the extracts produced were then analysed chromatographically using gas chromatography with flame ionisation or mass selective detection and high-performance liquid chromatography. The carbohydrates were next analysed using acidic hydrolysis and acidic methanolysis, followed by chromatographic separation of the monosaccharides formed and their derivatives. The results showed that the most intensive degradation occurred during the first 4 weeks of storage. The levels of hydrophilic extractives were also found to decrease drastically (69% in normal pile and 73% in snow-covered pile) during storage, whereas the decrease in hydrophobic extractives was relatively stable (15% in normal pile and 8% in snow-covered pile). The top of the piles exhibited the most significant decrease in the total level of extractives (73% in normal and snow-covered pile), whereas the bark in the middle of the pile retained the highest amount of extractives (decreased by 51% in normal pile and 47% in snow-covered pile) after 24-week storage.

Keywords: bark; Norway spruce; storage; degradation; extracts; tannins; stilbenes; gas chromatography; high pressure liquid chromatography

Free keywords: pile storage; wood extractives; condensed tannins; stilbenes; gas chromatography with mass selective detection (GC-MS); high-performance liquid chromatography (HPLC)

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2022

Preliminary JUFO rating: 1

Last updated on 2022-20-09 at 13:45