Research On The Preparation,Properties And Application Of PH-Sensing Smart Food Packaging Films

Novel food packaging films based on ?-carrageenan(Car)incorporated with curcumin(Cur)were developed by casting method.Cur andCar wereinteracted by hydrogen bonds.A low amount of Cur(no less than 3%)could be well-dispersed in Car matrix and was partially in crystalline form.These characteristics significantly improved the film barrier and tensile strength besides the enhancement of thermal stability.The films showed a good release control of Cur and a predominantFickian diffusion release mechanism,which was favorable to sustainable pH color sensing.The Car-Cur films demonstrated a strong redness-shift under alkaline condition.The results showed that the level of TVBN has risen and the color of the films was changed from yellow to red during storage.A novel wide pH–sensing colorimetricantioxidation film of ?-carrageenan incorporated with extract from Lyciumruthenicum Murr.(Car-LRM)were developed by casting method.A low incorporation of LRM(no more than 2.5%)led to an enhancement in thermal stability and water vapor barrier of films to a certain extent.At above level of incorporation,LRM could be well-distributedin Car matrix by the interactions of hydrogen bonds.The film displayed colorimetric response at a wide range of pH(2–10)and the color change was reversible.The addition of LRM weakened the mechanical properties and oxygen barrier properties of the films to some extent,but is still within acceptable limits.The antioxidant ability of the films was determined by DPPH method.The release of LRM from films followed Fick's law which was controlled by diffusion mechanism.The successful applications of Car-LRM for the freshness monitoring of milk and shrimps indicated that Car-LRMmay have a great potential in monitoring the freshness of milk and aquatic products.