The Potential Value of Debarking Water as a Source of Polyphenolic Compounds for the Specialty Chemicals Sector

Forest-based industries produce huge quantities of bark during their primary processing activities. In Nordic pulp and paper industries, where a wet debarking process is used for bark removal, toxic debarking water and bark press water are produced as a by-product. However, polyphenols represent an important fraction of the debarking water and bark press water. These polyphenolic compounds are of commercial interest in chemical specialty sectors since polyphenols have been proven to have diverse health benefits, and after collecting them from waste sources, they can act as alternatives to oil-based chemicals. Determining the economic potential of polyphenolic compounds, identifying their molecular structure, and determining the antioxidant capacity of these compounds present in debarking water and bark can support the identification of their potential applications. The results show that water extractions from bark have a lower efficiency than (partial) alcoholic extractions. Nevertheless, a considerable amount of low-molecular polyphenolic compounds, which are of interest for high-end applications, was found in all extracts. Bark press water has a highly versatile range of polyphenolic compounds and showed some antioxidant activity, making it a great source for the collection of polyphenolic compounds, in contrast to debarking water, which had a much lower polyphenolic content and low antioxidant activity.

Automated summary

Forest-based industries generate large quantities of bark during primary processing, and in the Nordic pulp and paper industries, toxic debarking water and bark press water are produced as by-products. These waters contain polyphenolic compounds, which have commercial value and can serve as alternatives to oil-based chemicals. Evaluating the economic potential, molecular structure, and antioxidant capacity of these compounds can help identify their potential applications. Water extractions from bark showed lower efficiency compared to alcoholic extractions, but all extracts contained a considerable amount of low-molecular polyphenolic compounds suitable for high-end applications. Bark press water had a versatile range of polyphenolic compounds and exhibited antioxidant activity, making it an excellent source for collecting polyphenolic compounds, in contrast to debarking water with lower polyphenolic content and antioxidant activity.