The Regulation On Gas Permeability Of Poly(L-lactic Acid) Based On Equilibrium Modified Atmosphere Packaging Of Strawberry

The experiment was aim at preparing a new type cling wrap for equilibrium modified atmosphere packaging to extend the shelf life of strawberry.First,the PLLA-PCL-PLLA triblock copolymer was prepared,and its properties of packing were investigated by 1HNMR,X-ray,FTIR,DSC,tensile test and gas permeability.The result showed that the high molecular weight copolymer was synthesized successfully and the insert PCL segment greatly improved the brittleness of PLLA and the elongation at break of PLCLx films increased with increasing PCL content.The elongation at break of PLCL25 was 210%and about 35 times of neat PLLA.In addition,the PLCLx films has much better gas permeability and CO2/O2 perm-selectivity than neat PLLA,the perm-selectivity ratio also increased with increasing PCL content and the maximum ratio can reached 7.45.This to say the PLCLx films were more suitable for modified atmosphere packaging of strawberry.Further use those films in equilibrium modified atmosphere packaging of strawberry in cold storage.The result showed that PLCL35 and PLCL25 restrained a steady-state atmosphere about 5?9%O2,8?9%CO2 from the 8th day due to the better gas permeability of films.The strawberry kept good sensory quality and less nutrient loss during storage.