Extraction of hemicellulose and condensed tannin from spruce bark

Tannin industry is looking for new industrial sources for condensed tannins due to the limited availability of the current raw materials such as Acacia bark and quebracho wood. Spruce bark is a promising source of polyphenolic compounds including condensed tannins, which can be extracted in an unpressurized hot water treatment. In addition to phenolic compounds, hot water extraction dissolves a large amount of hemicellulose and monosaccharides from spruce bark. To be able to fractionate these two groups of compounds and to find uses for the extractable bark sugars, it is important to understand the effect of extraction parameters to the extract composition and its sugar profile. The research leading to these results has received funding from the WoodWisdom-Net Research Programme which is a transnational R&D programme jointly funded by national funding organisations within the framework of the ERA-NET WoodWisdom-Net 2.