Preparation Of High Barrier Functional Fresh-keeping Paper And Study On Its Fresh-keeping Performanc

Nowadays,cold chain is a common fresh-keeping method for fruit transportation.However,due to the high cost of cold chain and large investment in equipment in China,the picking end of“the first kilometer”and the distribution end of“the last kilometer”can′t form a closed loop.As a main component of plants,hemicellulose is often used as a fresh-keeping coating for fruits and vegetables with excellent oxygen barrier properties.However,due to the inherent hydrophilic properties of hemicellulose-based membrane materials,it is very easy to disintegrate the coating structure and reduce the barrier properties in the cold chain environment with high humidity,resulting in the loss of fresh-keeping function of hemicellulose-based membrane materials.To address these drawbacks,the paper uses paper as the base material and hemicellulose composite preservative film solution as the coating agent to prepare preservative paper with high strength and high gas barrier characteristics,which can be applied to high humidity environment.It is used to solve the fundamental drawbacks of the decline of strength and barrier properties of traditional hemicellulose-based film materials in high humidity environment.The strength and barrier properties of coated preservative paper under different humidity environments were studied.It was found that the tensile strength and elongation at break of the preservative paper with HC/PVA/CNF/MMT/AKD film agent in 95%RH humidity environment on the 10th day were still able to reach 37.28 MPa and 27.44%,respectively.And the oxygen and carbon dioxide gas transmission rates can still be maintained at 8.78 and 5.89 cm~3/(cm~2·d·(0.1MPa))separately during this period,which meets the preservation conditions in the cold chain environment.The preservation of kiwifruit with HC/PVA/CNF/MMT/AKD surface-coated paper was studied,the results showed that the surface-coated paper could prolong the marketable life of kiwifruit for at least 3 days at 13%～95%RH humidity at room temperature.The browning index of kiwifruit was studied.It was found that the lipoxygenase(LOX),cell conductivity and browning index of kiwifruit treated with surface-coated paper showed a downward trend during storage compared with the control group.For example,in the 95%RH humidity environment,the browning index(BI)of the kiwifruit group was 0.059 on the 7th day.The BI of the control kiwifruit group was 0.209,and the surface-coated paper effectively inhibited its browning and improved the preservation quality,especially solved the browning problem caused by excessive cell water absorption of kiwifruit in high humidity environment.At the same time,the change trend of polyphenol oxidase(PPO)activity of kiwifruit was found.The PPO activity and environmental humidity of kiwifruit in the preservation group during storage conformed to the second-order kinetic model:y=3.816892×0.05511x/(1+3.81689×0.05511x),which provided a theoretical basis for the preservation effect of high barrier surface-coated paper on inhibiting kiwifruit browning in high humidity environment.