High-strength collagen/delphinidin film incorporated with Vaccinium oxycoccus pigment for active and intelligent food packaging

This study developed an active and intelligent collagen-based packaging film with high strength for visually monitoring the freshness of fish.The results of scanning electron microscopy and atomic force microscopy showed that the film based on cross-linked collagen/delphinidin catalyzed by laccase exhibited a denser layer structure and a rougher surface.The dry and wet tensile strengths of the laccase-catalyzed collagen/delphinidin film(Col/Dp-LA film)increased by 41.74 MPa and 13.13 MPa in comparison with that of the pure collagen film,respectively.Moreover,the Col/Dp-LA film presented good antioxidant and barrier properties demonstrated by the results of free radical scavenging rate,light transmission rate,and water vapor permeability.The intelligent collagen-based film was obtained by incorporating Vaccinium oxycoccus pigment into the Col/Dp-LA film,which could change color under different pH values.When applied to the preservation offish fillets,the film could release Dp to minimize oxidative rancidity and prolong the shelf life of the fish for 2 days.Meanwhile,the film showed visual color changes from purplish-red to greyish-blue after the fish spoilage.These results indicated that the collagen film treated with delphinidin,laccase,and Vaccinium oxycoccus pigment has potential application value in the field of active and intelligent food packaging.

Generation of Tough Poly(glycolic acid)(PGA)/Poly(butylene succinate-co-butylene adipate)(PBSA)Films with High Gas Barrier Performance through In situ Nanofibrillation of PBSA under an Elongational Flow Field

Poly(glycolic acid)(PGA)is derived from glycolide obtained by fermenting pineapples or sugarcane,which has excellent gas barrier properties and a small carbon footprint.PGA is a potential substitute for the current aluminum-plastic composite films used in high barrier packaging applications.However,its poor ductility and narrow processing window limit its application in food packaging.Herein,poly(butylene succinate-co-butylene adipate)(PBSA)was used to fabricate PGA/PBSA blend films through an in situ fibrillation technique and blown film extrusion.Under the elongational flow field used during the extrusion process,a unique hierarchical structure based on the PBSA nanofibrils and interfacially oriented PGA crystals was obtained.This structure enhances the strength,ductility and gas barrier properties of the PGA/PBSA blend film.In addition,an epoxy chain extender(ADR4468)was used as a compatibilizer to further enhance the interfacial adhesion between PGA and PBSA.70PGA/0.7ADR exhibited a very low oxygen permeability(2.34×10^(-4)Barrer)with significantly high elongating at break(604.4%),tensile strength(47.4 MPa),and transparency,which were superior to those of petroleum-based polymers.Thus,the 70PGA/0.7ADR blown films could satisfy the requirements for most instant foods such as coffee,peanuts,and fresh meat.

Antibacterial and antioxidant water-degradable food packaging chitosan film prepared from American cockroach

Traditional food packaging films made of plastic have caused serious damage to the environment.Chitosan film is a potential substitute but it is weak in antioxidant activity.In this study,the extract and chitosan from American cockroach were combined to produce a new environment-friendly chitosan film for food packaging.The chitosan film was easily degraded by water,avoiding accumulation in the environment.The addition of American cockroach extract improved the antioxidant activity of the chitosan film(up to 50 times higher than that of pure chitosan film when considering reducing capacity)and did not weaken its efficient antibacterial activity.In practical application,the packaged food was protected by the chitosan film from fast decay and oxidation for 15 days and 48 h,respectively.These results suggested that the new chitosan film possessed the potential for food packaging and improved the value of American cockroach.

Effect of sodium alginate/phosphate-stabilized amorphous calcium carbonate nanoparticles on chitosan membranes

Biodegradable chitosan(CS)films can meet the demand for sustainable development.However,the performance of pure CS membrane still exists a particular gap compared with the traditional film.Inorganic nanomaterials with the controllable release are added to improve its physical and chemical properties.Herein,a series of CS/phosphate-stabilized amorphous calcium carbonate(CS/ACCP)and CS/sodium alginate/ACCP(CS/Alginate/ACCP)composite films were prepared by the flow method.The effects of ACCP and Alginate/ACCP nanoparticles on the physical and chemical properties of the composite membrane were investigated.The results showed that the composite nanoparticles could significantly improve CS film’s compactness,hydrophobicity,and mechanical properties and enhance its ultraviolet(UV)blocking ability,water resistance,and water vapor blocking ability.When the number of nanoparticles was 8%,the mechanical properties of the CS composite membrane reached optimum value,and the comprehensive performance was better.In addition,the controlled-release properties of CS composite membranes were also studied,and the antioxidant,antibacterial,biocompatibility,and fresh-keeping effects of the composite membranes were explored.The results indicated that the CS composite membranes had not only excellent bacteriostatic(72%)properties(Escherichia coli)but also presented well fruit preservation(15 days)properties(sugar orange).In particular,the controlled release range of CS composite membrane at 12 h was between 30%and 90%,which provided a theoretical basis for its use as an edible membrane.Therefore,based on ACCP and Alginate/ACCP nanoparticles,CS composite membranes with more excellent application value in the biological field were prepared through further optimization design.