Abstract
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•Modification of alkynyl group and alkynyl silver on CS increased its viscosity.•Ag-CS demonstrated dose dependent antimicrobial effects against bacteria strains.•Ten μg/mL Ag-CS suppressed the growth of E. coli under detection limit.•The TVB-N generated by Ag-CS coated shrimps were 3 times less than control group.•The Ag residue left in Ag-CS coated shrimp after storage was 0.145 mg Ag / kg meat.
Chitosan was modified by substituting alkynyl silver on chitosan (Ag-CS) through a two-step chemical modification to form a novel antimicrobial coating material. The physicochemical property, antimicrobial activity, cytotoxicity, and potential food applications of Ag-CS were systematically investigated. The Ag-CS presented a smooth sheet structure, and demonstrated stronger antimicrobial effects than either silver acetate (AgOAc) or silver nitrate (AgNO3) against both Gram positive and Gram negative bacteria strains. Ag-CS also demonstrated a controlled release of Ag for over 5 days, whereas AgOAc or AgNO3 infused chitosan released over 90 % Ag within 4 h. Ag-CS coating on shrimps significantly extended their shelf-life. Overall, our results revealed that the newly developed Ag-CS antimicrobial coating material possesses strong antimicrobial efficacies with a sustained Ag release property, and its ability to slow down the spoilage rate of shrimps indicates its potential in the improvement of food quality and shelf life.
