Preparation, characterization and antioxidant activity of two partially N-acetylated chitotrioses

► An N-acetylated chitotriose mixture is prepared. ► N-acetylchitotriose (D2A) and N,N′-diacetylchitotriose (DA2) were separated. ► The main isomers of D2A and DA2 were DDA and ADA, respectively. ► N-acetylation enhanced the antioxidant activity of chitotriose.