Synthesis and preservative application of quaternized carboxymethyl chitosan containing guanidine groups

A chitosan derivative, quaternized carboxymethyl chitosan containing guanidine groups (QGCMC), was synthesized and structurally characterized using FT-IR, (1)H NMR spectroscopy. The elemental composition of QGCMC was also investigated. Increase in the molar ratio of materials used for QGCMC synthesis and an increase in the reaction time of QGCMC synthesis led to an increased degree of substitution. QGCMC demonstrated a strong antimicrobial activity at acidic, neutral, and basic pH conditions and could significantly lengthen the shelf life of strawberries.