Adsorption of apple xyloglucan on cellulose nanofiber depends on molecular weight, concentration and building blocks.

Apple xyloglucan (XyG) structural features (molecular weight and building motifs) were studied in relation with the hemicellulose interaction with cellulose nanofiber (CNF) through adsorption isotherm, high performance size exclusion chromatography and high-performance anion exchange chromatography analyses. Up to 75.6 μg of apple XyG adsorbed/mg of CNF. XyG adsorption depended on both Mw and XyG/CNF ratio. The adsorption capacity increased with Mw irrespectively of XyG/CNF ratio. At XyG/CNF ratio > 0.05, the adsorption of high Mw populations (2.0 × 10, 7.9 × 10 g mol) gradually ceased, while it kept increasing for low Mw populations (2.6 × 10, 1.2 × 10 g mol). The unbranched glucan segments and the galactosylated XLLG motif showed the highest binding affinity to CNF. Most of the XLLG motif was found in "loops and tails", whereas most of the XyG unbranched glucan segments interact directly with CNF.