Surface-treated carboxyalkylated polysaccharides comprising a biobased content of at least 82% are described herein. The surface-treated carboxyalkylated polysaccharides comprise a CRC of at least 18 g/g, a FSC of at least 26 g/g, and an AUL at 0.7 psi of at least 14 g/g. Processes for the manufacture of surface-treated carboxyalkylated polysaccharides are also described herein.