Preparation And Application Of Gelatin/Essential Oil Nanofibers As Food Packaging

Food packaging,which could protect food from the external environment and prolong the storage time of food,is one of the research focuses in the field of food engineering.However,conventional packagings represented by plastic packagings have certain defects in the environmental friendliness of the materials and the efficacy on food preservation.Active packaging technology by loading various kinds of active substances(such as antibacterial agents,antioxidants,etc.)in natural-source packaging materials,not only can avoid the environmental pollution and waste of resources of traditional plastic-based packaging,but also can improve the quality of food preservation and preservation aging,thus has received more and more attention in recent years.Among various active packaging preparation techniques,electrospinning could achieve stable and efficient loading and sustained release of active substances in the electrospun nanofibers at room temperature conveniently and efficiently,which has become a research hotspot in the field of active packaging.In this thesis,we proposed several types of essential oil-loaded gelatin nanofiber materials prepared by blending electrospinning technology,in which natural polymer gelatin is applied as the main material and three natural plant essential oils are selected as active additives.The details are as follows:(1)Using gelatin and angelica essential oil(AEO)as raw materials,gelatin/AEO nanofibers were prepared via electrospinning.Scanning electron microscopy observation revealed that all groups of gelatin/EO nanofibers exhibited homogeneous and bead-free structures and no obvious difference from pure gelatin nanofibers.The proton nuclear magnetic resonance spectrum proved that AEO was incorporated in gelatin nanofibers successfully.The addition of AEO significantly improved the hydrophobicity of gelatin nanofibers.Gelatin nanofiber containing 9%(v/v)AEO exhibited a significant hydrophobic property.As the concentration of AEO increased,both the antioxidant and antibacterial activities of gelatin/AEO nanofibers were improved.Cytotoxicity experiments indicated that gelatin/AEO nanofibers were non-cytotoxic.(2)Using gelatin,peppermint essential oil(PO)and chamomile essential oil(CO)as raw materials,three kinds of nanofibers(gelatin/PO,gelatin/CO and gelatin/PO/CO nanofibers)were prepared by electrospinning technique.It was observed from the scanning electron microscope image that the addition of essential oils(EOs)had no significant effect on the morphology of the nanofibers.The proton nuclear magnetic resonance spectrum proved that essential oils were successfully incorporated in gelatin nanofibers.The water contact angle of gelatin nanofibers was increased by the addition of EOs.With the same percentage of EOs,gelatin/PO/CO nanofibers showed the water contact angle in between gelatin/CO and gelatin/PO nanofibers.The addition of the two kinds of EOs improved the antioxidant property and antimicrobial activity of nanofibers.Among them,the addition of CO in nanofiber resulted in better antioxidant property than that of PO,while the addition of PO showed better antimicrobial activity.Gelatin nanofibers loaded with two kinds of EOs showed overall optimum bioactivities compared that loaded with single PO or CO,possessing not only the excellent antibacterial property of PO,but also the outstanding antioxidant activity of CO.Cytotoxicity experiments revealed the non-cytotoxicity of all the three nanofibers.In summary,the successful preparation of the gelatin nanofibers encapsulated with different EOs via electrospinning in this thesis,which possessed good hydrophobicity,anti-oxidation,antibacterial and other activities,shows broad application potential in the field of active food packaging.The study would not only broaden the application fields of plant essential oils,but also provide new strategies for the function optimization of food packaging.