72 Novel food packaging techniques Food Food Fig. 5.1 Simplified visual comparison of (a) non-migratory and (b)migratory bioactive packaging. Adapted from Han(2000) medium(see Fig. 5. 1). Typically this is achieved through covalent attachment of he active component to the polymer backbone, inherently bioactive polymer backbones, or entrapment of the active component within the polymer matrix. The first two of these will be discussed in this chapter 5.2 Advantages of nMBP In order for any new technology to be considered, it needs to have advantages over existing technologies. Typically, however, these advantages come with in limitations, in application or utility, and frequently with an increase in Benefits and limitations will apply differently to the different types of NMBP The benefits of np can be divided into four main areas: technical benefits gulatory advantages, marketing aspects and the food processor's perspective Note that this list is not exhaustive; particular applications will involve some or all of these plus other considerations specific to that application Technical benefits nical benefits of NMBP include improved stability of the bioactive substance, and concentration of the bioactive effect at a specific locus. Improved stability is a consideration for covalently immobilised bioactive substances biological molecules, e.g. enzymes, are typically very sensitive to environmental conditions. They are readily denatured by some solvents, by high, and in some cases low, temperatures; by high pressures, high shear or ionising radiation; by certain levels of pH and in the presence of high concentrations of electrolytes chardon and Hyslop, 1985). Conjugation to polymer supports has been shown to enhance dramatically the stability of these molecules. Topchieva andmedium (see Fig. 5.1). Typically this is achieved through covalent attachment of the active component to the polymer backbone, inherently bioactive polymer backbones, or entrapment of the active component within the polymer matrix. The first two of these will be discussed in this chapter. 5.2 Advantages of NMBP In order for any new technology to be considered, it needs to have advantages over existing technologies. Typically, however, these advantages come with certain limitations, in application or utility, and frequently with an increase in cost. Benefits and limitations will apply differently to the different types of NMBP. The benefits of NP can be divided into four main areas: technical benefits, regulatory advantages, marketing aspects and the food processor’s perspective. Note that this list is not exhaustive; particular applications will involve some or all of these plus other considerations specific to that application. 5.2.1 Technical benefits Technical benefits of NMBP include improved stability of the bioactive substance, and concentration of the bioactive effect at a specific locus. Improved stability is a consideration for covalently immobilised bioactive substances; biological molecules, e.g. enzymes, are typically very sensitive to environmental conditions. They are readily denatured by some solvents, by high, and in some cases low, temperatures; by high pressures, high shear or ionising radiation; by certain levels of pH and in the presence of high concentrations of electrolytes (Richardson and Hyslop, 1985). Conjugation to polymer supports has been shown to enhance dramatically the stability of these molecules. Topchieva and Fig. 5.1 Simplified visual comparison of (a) non-migratory and (b) migratory bioactive packaging. Adapted from Han (2000). 72 Novel food packaging techniques