Preparation And Release Kinetics Of Tea Polyphenols Active Packaging Membrane

Food safety is the focus of the world,plastic as a commonly used food packaging film brings more and more serious environmental pressure,it is particularly important to study the food packaging material with fresh-keeping performance and biodegradable.Polylactic acid(PLA)is recognized as an environmentally friendly material,and Tea Polyphenols(TP)is widely used in food preservation because of its strong antioxidant properties,non-toxic and tasteless.In addition,in order to extend the shelf life of foods,the controlled release technology of active substances slowly from packaging film has been paid more and more attention by researchers.In this paper,PLA/TP films were prepared by solution casting method and electrospinning method,and the effects of preparation process and TP content on the properties of the films were studied,the effect of inner and outer layer thickness on the properties of the multilayer electrospun film with PLA/TP Nanofiber as the intermediate active film layer was analyzed,and the release of TP from different active film to food simulation solution was studied The fresh-keeping effects of different active packaging films on strawberry were compared under the same experimental conditions.The main conclusions of this paper are as follows:1.The PLA/TP composite casting film was prepared and the effect of TP content on the casting film was investigated.The results show that the tensile strength,elongation at break and contact angle of the composite membrane decrease with the increase of TP content,while the swelling rate and DPPH radical scavenging rate increase,the diffusivity increases with the increase of TP content,and the PLA/TP casting film shows excellent fresh-keeping performance,which could prolong the shelf life of strawberry to 18 days.2.PLA/TP composite electrospinning membrane was prepared,and the effects of TP content on the properties of the electrospinning membrane were studied.The results showe that with the increase of TP content,the tensile strength,elongation at break,contact Angle and swelling rate of the composite membrane decrease,while the DPPH radical scavenging rate increase.The kinetics of TP release in the composite membrane conforms to Higuchi model,and the diffusion coefficient increases with the increase of TP content.PLA/TP electrospun film shows good fresh-keeping performance and extend shelf life to 9 days.3.PLA/TP multilayer composite electrospinning membrane was prepared,and the effects of barrier layer on the properties of the electrospinning membrane were studied.The results show that with the increase of the barrier layer spinning liquid,the swelling rate and DPPH radical scavenging rate of the multilayer composite membrane decrease,while the tensile strength and elongation at break increase.The kinetics of TP release in the multilayer composite film conforms to the Higuchi model,and the diffusion coefficient decreases with the increase of the spinning liquid in the barrier layer.PLA/TP multilayer electrospinning films show excellent fresh-keeping properties,which can extend shelf life to 18 days.