Effect of Nano-SiOx on the Structure and Properties of Chitosan Coating for Fresh-keeping1

摘要

In the application of chitosan as fruit and vegetable' s fresh-keeping coating，there are some drawbacks, such as low toughness and low moisture content, which limit the use of chitosan. Therefore, we modified the chitosan with nano-SiOx which was pre-activated by anion surfactant (SDS), and then obtained nano-SiOx / Chitosan composite film. The composite films were characterized by Infra-red spectroscopy (IR), X-ray diffraction （XRD）and Transmission Electron Microscopy (TEM). Also, the water/oxygen permeability, mechanical properties and antibacterial activity were investigated. The fresh-keeping ability of the composite films was also evaluated by measuring the storage life of fruits and vegetables; the results indicated that strong hydrogen bonds were formed between chitosan and nano-SiOx. The water permeability and oxygen permeability decreased by 35% and 21% respectively and the Tensile strength, Elongation-at-break and Orthogonal Tear strength enhanced by 49％, 45％ and 8.5% respectively. It was also found that the composite film has obvious antibacterial activity and the fruit and vegetable fresh-keeping time was increased obviously. The fresh-keeping time of JINQIU pear was prolonged from 20 to 60 days and the good quality percent was 80% after 60 days.