Preparation And Characterization Of Antimicrobial Silver Carp Fish Skin Collagen-based Edible Films

Edible food packing film is a hot technology in the research of green packing field due to the properties of biodegrable and non-polluting as well as the high security and a certain nutritional value compared to the traditional packing film. Collagen is a kind of good film-forming substrate. However, the mechanical properties, water reistance, antimicrobial and antioxidation resistance of the collagen film are poor, thus carrying on the modification is an important issue in the study of edible packaging film. In this paper, collagen as film-forming substrate was extracted from silver carp fish skin, then natural plant essential oils were added into the film form solution to prepare the antimicrobial edible packaging film, essential oil nanoliposome and collagen film added with essential oil nanoliposomes are also prepared. In addition, the antimicrobial and physical-chemical properties of film were studies. This paper was consisted of three parts.(1) Different concentrations of cinnamon essential oil (CEO) and thyme essential oil (TEO) as antimicrobial additive were added into collagen-based films to prepare the antimicrobial edible packing film. Systematic studies conducted to investigate the effect of essential oils on the mechanical properties、hydrophilicity、morphology structure and the antimicrobial activity. According to studies, the addition of essential oils into the film improved the hydrophilicity, light barrier and antimicrobial properties of the collagen-film. The study suggested the film incorporated with CEO possessed the excellent comprehensive performances. Release experiment showed that the release rate of CEO in the collagen film into the corn oil solution was fast, and the higher the temperature was, the faster the release rate became. The antimicrobial activity of the film added with CEO reduced after the film was storage for 30 d.(2) In order to further improve the antimicrobial stability of the collagen-film incorporated with essential oils. CEO nanoliposomes were prepared by the thin film dispersion method and the best preparation processes were confirmed by single factors and orthogonal experiments. According to the process parameters in the preparation, particles size of the CEO nanoliposomes suspension distributed uniformly, meanwhile, the the CEO nanoliposomes showed high encapsulation rate and good stability.(3) The collagen-films incorporated with CEO and CEO nanoliposomes were prepared. Systematic studies conducted to investigate the effect of CEO and CEO nanoliposomes on the light barrier properties> water resistance properties、mechanical properties and the antimicrobial activity and a comparative study was also carried out. In contrast with the film added with CEO, the film added with CEO nanoliposomes showed the better light barrier properties、water resistance properties、mechanical properties. SEM suggested the surface of the film with CEO nanoliposomes displayed smoother and the cross section was more compact compared to the film with CEO. This microstructure reduced the path that water molecules transitted. Release experiments showed the film incorporated with CEO nanoliposomes can retard the release rate of essential oil of the film. Antimicrobial stability experiment showed the lower level of antimicrobial activity of film added with CEO nanoliposomes was lower than that of film added with CEO, the result showed CEO nanoliposomes can improve the antimicrobial stability of the films.