Preparation And Properties Of PH-responsive Chalcone-loaded PVA/PAA Functional Films

Recently,pH-responsive films have attracted widespread attention because of their ability to control the release of active substances by changing the pH of media.In this study,a pH-responsive antibacterial packaging film was developed using PVA/PAA and AEP,which was applied in the field of meat preservation.A pH-responsive PVA/PAA was prepared by using solution blending method and mild thermal crosslinking to connect PAA to PVA in the form of hydrogen and ester bonds.The addition of PAA decreased the relative crystallinity of PVA.PAA(less than6%)significantly improved the thermal stability,mechanical properties and barrier properties of the films.In particular,the decomposition temperature of PVA/PAA3 increased to 363.6 ℃(67 ℃ higher than that of pure PVA),the TS and YM increased by 49.7%,232.94%,OP decreased by 44.17%,and WVP decreased by 49.11%.The swelling behavior of the film was controlled by pH change of the solution.The swelling kinetics followed the Ritger-Peppas and Schott second-order model and was reversible,which confirmed the pH responsiveness of PVA/PAA and its practical application.The PVA/PAA3-AEP was prepared by adding the active substance AEP with antibacterial and antioxidant ability on PVA/PAA3 as the carrier,and AEP was bonded with PVA/PAA3 by hydrogen bond.The release kinetics of AEP is consistent with Korsmeyer-Peppas equation and first-order kinetics equation.The results show that the release process of AEP is non-Fickian diffusion,and the transport of AEP is a rate-limiting step.The scavenging efficiency of PVA/PAA3-AEP3 on DPPH· reached80%,which showed good antioxidant activity,and inhibited the growth of food-borne bacteria.The inhibitory efficiency of PVA/PAA3-AEP3 on L.monocytogenes,S.aureus E.coli was 71%,76% and 3.6% respectively.The ability of PVA/PAA3-AEP3 to keep pork fresh at room temperature was studied.It was found that the shelf life of pork could be effectively extended for 4 days at 25 ℃.Meanwhile,the TVB-N value of pork was monitored.It can be seen that the active defense release mechanism of PVA/PAA3-AEP3 may have great potential in the field of intelligent food packaging.