Influence of Molar Mass and Degree of Substitution on Water Solubility of DEAE-Functionalized Apple Glycans

Making sustainable biopolymers available as replacements for fossil-based additives requires fitting of physical and chemical properties. As β-1,4-linked hemicelluloses are soluble in water only to a certain extent, introduction of a functional group (ternary amines) is required to overcome this issue. The study showed that the reaction conditions for the etherification of glycans from depectinized apple pomace can be varied significantly while still obtaining the desired degree of substitution with high yields. Keeping the reaction temperature at 60 °C, the time can be lowered to 0.5–1 h, which saves up to 4 h in total, and the input equivalents of diethylaminoethyl can significantly be reduced up to 63% regarding numerical optimization. An important result was the strong increase in the water solubility by 200%, which is excellent for future applications in water-based coating systems.