EFFECTS OF TEMPERATURE AND HUMIDITY ON THE PERMEABILITY OF SOY PROTEIN ISOLATE FILMS

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 lead to the change in the permeability of the SPI film,which may lead to the change of the shelf life of the packaged food.Therefore,it is necessary to study the effects of temperature and humidity on the O₂permeability (Po₂) and CO₂ permeability (Pco₂) of SPI films.The results showed that Po₂and Pco₂of the SPI films increased significantly with temperature,showing very good agreement with the Arrhenius model.At low relative humidity (RH<33%),SPI films presented very low Po₂and Pco₂.For higher than 59%RH,Po₂and Pco₂increased greatly,and the increasing extent of Pco₂was greater.The results can provide data and references for the applications of SPI films as the edible packaging material or coating materials used in food processing.