Application of chitosan-ZnO nanoparticle edible coating to wild-simulated Korean ginseng root

Chitosan-ZnO nanoparticle (ZnONP) edible coating was applied to extend shelf life of wild-simulated Korean ginseng root (WsKG). In antimicrobial testing of various coating solutions (0.01, 0.02, 0.03% ZnONP), Bacillus cereus (Gram-positive) and Escherichia coli (Gram-negative) were most inhibited by the 0.03% chitosan-ZnONP solution. The 0.03% chitosan-ZnONP solution was finally used for edible coating of WsKG. In SEM analysis, the coat of chitosan and ZnONP was well-formed on the surface of WsKG. In isothermal storage tests (temperature: 5-20 °C, RH: 95%), microbial limit (4.70 log CFU/g) of total aerobic bacteria for non-coated and coated WsKG were reached at 3.9 and 6.3 weeks at 5 °C, 1.9 and 4.3 weeks at 10 °C, and 1.3 and 2.0 weeks at 20 °C, respectively. Mold occurred in the non-coated sample at 4 weeks at 5 °C, but not in the coated sample during 6 weeks. Chitosan-ZnONP edible coating was very effective in preserving WsKG.