Preservation of ginkgo (Ginkgo biloba L.) seeds by coating with chitosan/nano-TiO 2 and chitosan/nano-SiO 2 films.

In this study, the chitosan, chitosan/nano-TiO2 and chitosan/nano-SiO2 coating films were prepared, their physico-chemical properties were determined. Then the preservation of ginkgo seeds coating with these films were investigated during storage. The incorporation of nano-TiO2 and nano-SiO2 particles of the best formula enhanced the mechanical properties of the composite films, which improved the water-vapor and gas permeability. Chitosan coating incorporation of nano-TiO2 and nano-SiO2 particles could significantly decrease the decay rate, shrinkage rate, respiration rate, ethylene production rate, electrolyte leakage rate, superoxide anion (O2 ·- ) production rate and the accumulation of malondialdehyde (MDA) content. After storage, the firmness of seeds coated with chitosan alone and chitosan/nanocomposite were markedly higher than those of control. Higher activities of scavenger antioxidant enzymes including peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) were enhanced in the chitosan/nano-TiO2 and chitosan/nano-SiO2 coating treatments during storage time. Either the composite treatment of chitosan with nano-TiO2 or chitosan/nano-SiO2 exhibited desirable performance in inhibiting mildew occurrence, shrinkage and maintaining the firmness of ginkgo seeds, positively affect the antioxidant activity in ginkgo seeds, thereby leading to the enhancement of seed quality. Coating ginkgo seeds with chitosan/nano-TiO2 or chitosan/nano-SiO2 is a potential method for commercial preservation.