New ChromaQuest paper: nanocellulose from invasive plants as a carrier for berry anthocyanins

We’re pleased to share that our article “Invasive plant biomass as a source of cellulose nanofibrils for anthocyanin sorption” has been published open access in Industrial Crops & Products (253, 124622). The work brings together two waste streams that ChromaQuest cares about: stems of three invasive plants that are cleared from Latvian landscapes every year (Sosnowsky’s hogweed, Japanese knotweed and Canadian goldenrod), and the press residues left behind when berries are juiced. From the plant stems we produced cellulose nanofibrils (CNF) through delignification, ammonium persulfate oxidation and microfluidization, and from the berry residues of aronia, blueberry, blackcurrant and honeysuckle we extracted and purified anthocyanins, the pigments responsible for their red-to-purple colours.

The central question was whether these nanofibrils could take up anthocyanins and hold on to them. They can. CNF from Sosnowsky’s hogweed performed best, binding 16.18 mg of anthocyanins per gram experimentally, with a Langmuir-estimated maximum of about 28 mg g⁻¹, followed by goldenrod and knotweed CNF. Interestingly, sorption did not track crystallinity: the less ordered, less aggregated fibrils with more accessible hydroxyl and carboxyl groups bound more pigment, which points to hydrogen bonding and electrostatic attraction between the flavylium cations and the oxidised cellulose surface as the main interactions at the mildly acidic pH of the system. Just as important for ChromaQuest’s goal of more stable natural dyes, a preliminary desorption test showed no release of anthocyanins from the loaded CNF even in 96% ethanol. The pigments are retained within the fibrillar network, which supports the idea of CNF as a matrix that can protect anthocyanins rather than merely carry them, in line with earlier reports that immobilisation on nanocellulose improves the thermal and oxidative stability of polyphenols. The next steps in the project will look directly at long-term colour stability in these matrices and at how the pigment–cellulose interactions can be tuned.

This paper was a true team effort, and we want to thank all of the co-authors: Linards Klavins, Linda Ansone-Bertina, Laura Andze, Inese Filipova, Lasma Bugovecka, Raimonds Meija, Kristaps Sarsuns, Lauris Arbidans, Oksana Petricenko and Maris Klavins, spanning the University of Latvia, the Latvian State Institute of Wood Chemistry and Rīga Stradiņš University. Thanks also to VeryBerry Ltd for providing the berry press residues. The research was supported by the Latvian Council of Science through the ChromaQuest project (lzp-2024/1-0066). The full article is available as an open acces publication at https://doi.org/10.1016/j.indcrop.2026.124622.