From teak wood to pulping additives: Natural quinones emerge as alternatives to anthraquinone
A mini-review examines the potential of teak-derived quinones to improve alkaline pulping, while highlighting the safety, consistency and scale-up challenges
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A mini-review examines the potential of teak-derived quinones to improve alkaline pulping, while highlighting the safety, consistency and scale-up challenges
view moreCredit: https://www.sciencedirect.com/science/article/pii/S2369969826000757
Alkaline pulping must remove enough lignin to separate wood fibers while preserving the cellulose and hemicelluloses needed for pulp yield and quality. Anthraquinone (AQ) has served as an important cooking additive because its redox cycle can promote delignification and stabilize carbohydrates. However, concerns about potential carcinogenicity and impurities in commercial products have renewed interest in alternative compounds.
In a mini-review published in the Journal of Bioresources and Bioproducts, Peifu Kong examines whether quinones from teak (Tectona grandis) wood could provide another option. The review covers 19 scholarly publications, comparing synthetic AQ derivatives with teak extracts and individual teak-derived compounds, including 2-methylanthraquinone (2-MAQ), deoxylapachol and lapachol.
Several studies summarized in the review report encouraging results under specific laboratory cooking conditions. In eucalyptus kraft pulping, Myanmar teak extract reduced the kappa number—a measure associated with residual lignin—by approximately five to six points and increased pulp yield by about two percentage points compared with cooking without the additive. Other studies found that deoxylapachol promoted delignification, while lapachol reduced the active alkali requirement estimated for reaching a target kappa number in a particular kraft-pulping system.
The results also reveal substantial differences between compounds and extracts. Their effects depend on the wood feedstock, cooking chemistry, additive concentration, extraction method and chemical composition. Improvements in delignification or yield alone do not establish overall performance; pulp viscosity, brightness, carbohydrate retention and compatibility with mill operations also matter.
Safety remains a central concern. Although some studies reported low residual levels and negative Ames-test results for purified 2-MAQ under the conditions tested, these findings do not establish comprehensive toxicological or food-contact safety. Some crude teak extracts showed mutagenic responses in laboratory tests, underscoring the need to evaluate extracts separately from purified compounds.
The review concludes that teak-derived quinones are promising candidates, rather than ready-to-use replacements for AQ. Progress will require standardized extract composition, more comprehensive safety and residue testing, scalable recovery methods, independent replication and pilot-scale validation. Their potential environmental and economic benefits also remain to be demonstrated through process-level assessment.
See the article:
DOI
https://doi.org/10.1016/j.jobab.2026.100303
Original Source URL
https://www.sciencedirect.com/science/article/pii/S2369969826000757
Journal
Journal of Bioresources and Bioproducts
Journal
Journal of Bioresources and Bioproducts
Method of Research
Literature review
Subject of Research
Not applicable
Transparent coloring of wood: Balancing natural appearance with functional color design
Preserving wood grain while adding color
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Preserving wood grain while adding color.
view moreCredit: Faculty of Forestry and Wood Technology, University of Zagreb, Zagreb 10000, Croatia
Wood has long been appreciated as a natural material for furniture, interior decoration and architectural applications. Its visual appeal comes not only from its colour but also from its distinctive grain and texture. Conventional colouring methods can broaden the range of available appearances, but maintaining the visibility of these natural features while introducing a controlled colour remains a challenge.
Transparent colouring offers a way to approach this challenge. Rather than simply covering the wood surface with an opaque colour layer, the concept aims to introduce colour while allowing the underlying wood structure to remain visible. This creates opportunities to combine the natural character of wood with greater flexibility in product design.
However, achieving a visually attractive colour is only part of the challenge. Wood is a structurally heterogeneous material, and differences in its anatomy and surface characteristics can affect the uniformity of colour. The interaction between colouring materials and the wood substrate is therefore important to the final appearance. Colour stability and durability are also relevant considerations, particularly when coloured wood is exposed to light, moisture or repeated use.
These considerations make transparent colouring an interdisciplinary research topic involving wood science, colour chemistry, surface treatment and materials engineering. Progress in this area could help broaden the design options available to wood-based products while retaining the visual qualities that distinguish wood from other materials.
The review Transparent Colouring of Wood: A Review provides a dedicated examination of this research topic. A detailed assessment of the methods discussed in the article, their comparative performance and the specific research priorities identified by the authors requires verification against the full text. Nevertheless, the central challenge for the field is clear: developing reliable colouring approaches that combine controllable appearance with preservation of the natural wood structure.
By bringing attention to transparent colouring, this review highlights a research direction relevant to the continued development of value-added wood products. Further progress will depend on establishing effective ways to control colour, maintain visual transparency and ensure that the resulting appearance remains stable under practical conditions.
See the article:
DOI
https://doi.org/10.1016/j.jobab.2026.100308
Original Source URL
https://www.sciencedirect.com/science/article/pii/S2369969826000800
Journal
Journal of Bioresources and Bioproducts
Journal
Journal of Bioresources and Bioproducts
Method of Research
Literature review
Subject of Research
Not applicable
Article Title
Transparent Colouring of Wood: A Review
Article Publication Date
13-Oct-2026
Article Title
From anthraquinone to teak wood quinones: Redox additive candidates for alkaline pulping
Article Publication Date
10-Oct-2026
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