Irradiation-induced Maillard reaction with glucosamine: an advance strategy to modify chitosan

Abstract

In this study, Maillard reaction with glucosamine (GA) induced by gamma irradiation was applied for chitosan (CT) and oligochitosan (OC) to improve the solution stability and antibacterial activity under alkaline condition. The mixture solutions of CT and/or OC with GA were irradiated at the dose of 25 kGy to form the Maillard reaction products (MRPs) respectively. The formations of MRPs were determined by spectrophotometric analyses at the wavelength of 284 nm and 420 nm. The improvement effect caused by the Maillard reaction on the stability of CT and OC solutions in alkaline condition was evaluated through the increase of pH value at the precipitation point of the solutions before and after irradiation. The antibacterial activity of the solutions against Escherichia coli was also investigated. The results showed that the CT-GA MRPs and OC-GA MRPs solutions could be remain their stability at pH 7, and the pH values at the precipitation point were 7.4 and 11.5 respectively. Moreover, at pH 7, the MRPs solutions exhibited high antibacterial activity with the reduction of ~ 4 log CFU/ml over control sample. Furthermore, 5-hydroxymethylfurfural (5-HMF), a known cytotoxic product formed by heat-induced Maillard reaction was not detected in both irradiated CT-GA and OC-GA solution. These results prove that the irradiation-induced Maillard reaction is an effective strategy to modify chitosan, and the MPRs of CT/OS with GA had a great potential to replace synthesis additives as a natural preservative for food applications