Antioxidative and antimicrobial effects of low molecular weight shrimp chitosan and its derivatives on seasoned-dried Pangasius fillets

This study was performed to evaluate the efficacy and applicability of low molecular weight shrimp chitosan (LMWC) and its derivatives (chitosan nanoparticles, CN; chitosan hydrochloride salt, CHS) as a preservative against lipid oxidation and microbial growth in seasoned-dried Pangasius hypophthalmus fillets during storage. All chitosans exhibited antioxidant activity in vitro (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, total reducing power ability and lipid peroxidation inhibition activity). The lipid oxidation in dried pangasius fillets that were seasoned by immersing in a solution containing 1.5% chitosan was suppressed during the 8-week storage; such effect was more effective than immersing in a solution containing 0.05% vitamin C. Likewise, LMWC and its derivatives were more effective in inhibiting microbial growth (lower total viable count and yeast/mould counts) than the control. These results clearly show that LMWC and its derivatives could be a potent antioxidant and antimicrobial preservative in seasoned-dried pangasius fillets during 8-week storage at 20 degrees C.