ABSTRACT
Films and coatings are thin layers, which can be used to protect foodstuffs by covering/wrapping or direct coating on the food surface. Films are generally preformed material and coatings are liquids, in which foods could be dipped. Biodegradable packaging has been known as an important eco-friendly approach to reduce plastic wastes. Nevertheless, lms from synthetic polymers generally have superior properties to biodegradable lms. To tackle this problem, the appropriate modications of biodegradable lms are required. Collagen and gelatin are commonly obtained from bovine hides, bones, and pigskins. Nowadays, gelatin and collagen from aquatic animals are gaining increasing attention due to health issues and religious constraints of mammalian counterpart. The industrial use of collagen and gelatin obtained from nonmammalian source is therefore rising signicantly. Collagen lms/coatings have numerous applications in the eld of medical, pharmaceutical, and cosmetics. Due to their lm-forming abilities, lms/ coatings from gelatin can be used to preserve foodstuffs and extend their shelf life. Mechanical properties of lms and barrier properties of lms/coatings mainly depend on the molecular weight distribution and
Abstract .................................................................................................................................................. 103 6.1 Introduction .................................................................................................................................. 104 6.2 Films and Coatings ...................................................................................................................... 104
6.2.1 Denition ......................................................................................................................... 104 6.2.2 Traditional Starting Materials for Protein Films and Coatings ...................................... 105
6.3 Collagen and Gelatin .................................................................................................................... 105 6.3.1 Sources ............................................................................................................................ 105 6.3.2 Molecular Characteristics................................................................................................ 105
6.4 Collagen/Gelatin Films and Coatings .......................................................................................... 106 6.4.1 Film Formation Processes ............................................................................................... 106 6.4.2 Parameters Affecting Properties of Film/Coating .......................................................... 107
6.4.2.1 Intrinsic Factors ............................................................................................... 107 6.4.2.2 Processing Parameters ..................................................................................... 108 6.4.2.3 Film Drying Condition .................................................................................... 108 6.4.2.4 Some Additives and Protein Modiers ............................................................ 109 6.4.2.5 Ultraviolet, γ-Irradiation, and Other Physical Treatments ...............................112
