Preparation And Characterization Of Potato Peel Active Film Containing Bacterial Cellulose And Curcumin

Plastic-based packaging materials are popular among consumers because of their convenient use and excellent performance,but they have seriously endangered the environment.In recent years,the development trend of using waste from food processing as packaging material has become more and more intense.By developing environmentally friendly biodegradable packaging materials,and the maximum utilization of resources can be achieved.However,due to current problems such as poor barrier properties and low brittleness and flexibility,they cannot be applied in actual production.Based on the above,it is necessary to use modifiers in the biodegradable materials or to exploit new processing film technology to improve film various properties.On this basis,adding active substances to new packaging materials,the films were endowed with certain properties to protect food from environmental damage.In this study,the whole potato peel powder was used as film-forming substrates to maximize the utilization of wastes.Bacterial cellulose(BC)was used as the modifier to add to the matrix in order to increase tensile strength and barrier properties of potato peel films.Finally,curcumin was added to the films.Adding curcumin to the film gives it special properties.The results are as follows:(1)3% and 5%(w/w)potato peel powder was used as film-forming matrix,biopolymer films was prepared using different concentration of BC(0%,5%,10% and 15%)as modifier,and adding glycerol as plasticizer to improve the flexibility of biopolymer films.Scanning electron microscopy(SEM)images showed that BC had good biocompatibility with potato peel,and the film structure was uniform and compact.However,excessive BC(15%)aggregated in the matrix and destroyed the microstructures of biopolymer films.X-ray diffraction(XRD)results indicated the addition of BC increased the crystallinity of the films and reduced the amorphous region.Fourier transform infrared spectroscopy(FTIR)showed that hydrogen bonding occurred between potato peel and BC.However,thermogravimetric analysis(TGA)showed that the addition of BC did not significantly improve the thermal stability of potato peel films.(2)From macro perspective,the tensile strength(TS)of 3% and 5% biopolymer films increased with the addition of BC,reaching the maximum at 10% BC,which were 11.30 ± 1.03 MPa and 13.87 ± 2.44 MPa,respectively.When BC was added to 15%,the TS decreased.In addition,BC reduced water vapor permeability(WVP)and oxygen permeability(OP)of the 3% and 5% composite films.The variation trend of WVP and OP was opposite to that of the TS,which first decreased(10% BC)to the optimum level,and then increased slightly(15% BC).The results showed that the strength of the new composite films increased and the damage of water and oxygen to food in the environment was alleviated.The addition of BC increased the opacity of the films and the optical shielding effect was better.(3)Potato peel and cortex contain polyphenols,which have certain antioxidant effect.The addition of curcumin improved the antioxidant activity of bacterial cellulose-potato peel films,and the polyphenols released by the films in fat system were higher than those in alcohol food simulation system.Films containing 1-5% curcumin had good free radical scavenging ability,and had a positive correlation with the amount of curcumin added.The ability of active films to scavenge ABTS and DPPH radicals is different,which is due to the different systems of the two methods.ABTS test is suitable for hydrophilic and high color food,while DPPH is suitable for hydrophobic food system.(4)Fresh pork was packaged with BC-potato peel film without curcumin for 7 days at 4 °C.The MDA content was increased from 0.44 ± 0.03 to 1.00 ± 0.01 nmol/mg.Pork wrapped with 1% and 5% curcumin active films reduced the MDA content(0.84 ± 0.07 and 0.72 ± 0.05 nm/mg,respectively)compared to the control(1.00 ± 0.01 nmol/mg).That is,packaging fresh pork with potato peel film containing curcumin can effectively delay the degree of lipid oxidation,especially for high fat products.Moreover,the active films can slow down the shelf life of fresh meat products due to deterioration caused by ultraviolet light.(5)The addition of BC in the potato peel film improves the mechanical properties and barrier properties of the film,and increases the shielding effect on visible light.Further addition of curcumin imparts a certain antioxidant capacity to the film and delays the degree of lipid oxidation of the meat product.