Compared with synthetic packaging materials,edible biopolymer has outstanding advantages,such as easy to degrade and good mechanical performance. The soy protein isolate(SPI) film is a kind of edible biopolymer,and SPI film can be obtained by adding soy protein isolate,glycerol and distilled water during the preparation of the film forming solution. As a polymeric material,SPI film is sensitive to environmental changes.In the process of storage and circulation,different ambient temperature and humidity can ...