Application Of Ginger Leaf Extract/Chitosan Composite In Food Packaging And Its Preservation Coating In Strawberry

Plastic food packaging materials pose a serious threat to terrestial and marine ecosystems,as well as human health,due to their slow degradation.Therefore,developing new biodegradable packaging material is crucial.Natural polymers offer good biocompatibility and degradability,and incorporating natural antimicrobial agents or antioxidant substances can create active packaging materials that extend the shelf life of food products.Ginger leaves are rich in polyphenol flavonoids with antioxidant and antimicrobial properties,making them valuable for active packaging materials.Ginger leaves as waste are produced in large quantities and difficult to handle.To make effective use of the waste,we extracted polyphenol flavonoids from ginger leaves and compounded chitosan polymers to prepare a new type of food packaging film with antioxidant and antibacterial activity.Additionally,we developed a fruit preservation coating solution that effectively preserves strawberries.The specific studies are as follows:(1)Extraction process of active substances based on flavonoids in ginger leavesThe optimum extraction scheme of active substances from ginger leaves was obtained through single-factor orthogonal experiments,The best conditions were the material-liquid ratio(mass of ginger leaf powder/volume of ethanol extract)=1/20(g/m L),the mass-percentage concentration of ethanol in the extraction solution was 60%,the sonication time was 45 min,and the extraction temperature was 60°C,which resulted in highest extraction rate of the highest flavonoid(26.23 mg/g),and the measured polyphenol content was 12.11 mg/g.(2)Study on the application of ginger leaf extract/chitosan composite in food packagingThe FT-IR found that adding ginger leaf extract to chitosan resulted in a strong interaction between the phenolic ketone hydroxyl groups and the amino and hydroxyl groups of chitosan molecules.XRD analysis showed reduced diffraction peaks of composite film,and SEM patterns indicated compatability between ginger leaf extract and chitosan.The composite film had decreased light transmission(with UV transmission at 200-320 nm almost reduced to zero),water content,and swelling properties,as well as decreased,Compared with pure chitosan,the inhibition zone diameter of E.coli in CG3 group was significantly increased from 6.79±0.23~dmm to 11.61±0.54~amm,and that of S.aureus was significantly increased from 7.37±0.13~dmm to 12.99±0.26~amm,and the DPPH free radical scavenging rate was increased by 49%.The antioxidant activity was significantly improved.Overall,the composite film showed enhanced photoresist,antioxidant,and antibacterial properties,making it a promising material for food packaging.(3)Formulation of ginger leaf extract/chitosan preservation coating solution and its application in strawberry preservationA ginger/chitosan preservation coating was prepared for strawberry preservation.Comparing with the control group,the coating group could maintain better color,hardness,weight,soluble solid content and titratable acid content.After 8 days of storage,the soluble solid content increased and then decreased,the titratable acid content decreased significantly,the total color difference increased.Mycorrhizal growth was evident in the uncoated group and no spoilage was observed in the strawberry group after ginger leaf extract/chitosan composite film.On the 8th day,the weight of the control group was significantly reduced with a weight loss of 31.3%,while the weight loss of the CG3 group was only 20.5%after treatment,indicating that ginger leaf extract/chitosan coated film has good water retention effect.The coating solution with the ratio of CG3 group had the most significant effect on preserving the freshness of strawberries.Overall,the ginger leaf extract/chitosan coating solution is a promising method for preserving the freshness of strawberries.