8
modity thermoplastics, such as poly(ethylene) (PE) and poly(propylene) (PP). The
modification of these materials by incorporating organic and inorganic nanoparticles (NPs) is a promising route to obtain AP, since their final properties can be tailored to specific product requirements.
2.2 AP Films
In order to extend the product shelf-life, AP design must take into account several
processes that occur in the packaged product: (1) physiological process which can
be evidenced during respiration, such as in fresh fruits and vegetables, (2) chemical
processes that can, for example, be detected in lipid oxidation, (3) physical processes which are present in staling of bread or dehydration, (4) microbiological
processes as in the case of putrefaction by microorganisms and (5) infestation by
insect attack.
The purpose of AP is to preserve and protect the product against spoilage and
microorganism attack. In this technology, an active component is incorporated into
packaging films which, by interacting with internal or external factors, promote
actions that extend the product shelf-life, and preserve its quality and safety. This
component performs its activity by itself or by chemical reaction, resulting in a
beneficial influence on the packaged food. Depending on the requirements of certain food products, a mixture of active components is included in the packaging
materials. These components can release and/or absorb substances into/from the
product or the surrounding. In this sense, AP technologies can be classified into
absorbing (scavengers) and releasing (emitters) systems (Fig. 2.1). There are different active components that play a specific role in the protection and preservation of
foodstuffs, such as antimicrobials, carbon dioxide (CO 2 ) and O 2 scavengers, ethanol
emitters and ethylene and moisture absorbers (Bhardwaj et al. 2019).
2.3 Classification of AP
AP systems can be divided into scavenging and emitters. Regarding the absorbing
systems, their functions are to eliminate undesirable substances from the foodstuff
or the head-space of the packaging such as CO 2 , O 2 , ethylene, moisture, odor, among
others. On the other hand, the active character of the release systems consists in
delivering specific compounds to the packaged foodstuff or into the atmosphere
such as CO 2 , ethanol, ethylene, flavors, as well as antimicrobial and antioxidant
compounds and preservatives. Figure 2.2 shows the active agents used for food
packaging applications. When products require more than one active agent, combinations of compounds with different functionality are incorporated into the packaging system. It is important to mention that the selection of active agents depends
mainly on the characteristics of the product. In this way, antioxidants are used in
Y. N. Alonso et al.
modity thermoplastics, such as poly(ethylene) (PE) and poly(propylene) (PP). The
modification of these materials by incorporating organic and inorganic nanoparticles (NPs) is a promising route to obtain AP, since their final properties can be tailored to specific product requirements.
2.2 AP Films
In order to extend the product shelf-life, AP design must take into account several
processes that occur in the packaged product: (1) physiological process which can
be evidenced during respiration, such as in fresh fruits and vegetables, (2) chemical
processes that can, for example, be detected in lipid oxidation, (3) physical processes which are present in staling of bread or dehydration, (4) microbiological
processes as in the case of putrefaction by microorganisms and (5) infestation by
insect attack.
The purpose of AP is to preserve and protect the product against spoilage and
microorganism attack. In this technology, an active component is incorporated into
packaging films which, by interacting with internal or external factors, promote
actions that extend the product shelf-life, and preserve its quality and safety. This
component performs its activity by itself or by chemical reaction, resulting in a
beneficial influence on the packaged food. Depending on the requirements of certain food products, a mixture of active components is included in the packaging
materials. These components can release and/or absorb substances into/from the
product or the surrounding. In this sense, AP technologies can be classified into
absorbing (scavengers) and releasing (emitters) systems (Fig. 2.1). There are different active components that play a specific role in the protection and preservation of
foodstuffs, such as antimicrobials, carbon dioxide (CO 2 ) and O 2 scavengers, ethanol
emitters and ethylene and moisture absorbers (Bhardwaj et al. 2019).
2.3 Classification of AP
AP systems can be divided into scavenging and emitters. Regarding the absorbing
systems, their functions are to eliminate undesirable substances from the foodstuff
or the head-space of the packaging such as CO 2 , O 2 , ethylene, moisture, odor, among
others. On the other hand, the active character of the release systems consists in
delivering specific compounds to the packaged foodstuff or into the atmosphere
such as CO 2 , ethanol, ethylene, flavors, as well as antimicrobial and antioxidant
compounds and preservatives. Figure 2.2 shows the active agents used for food
packaging applications. When products require more than one active agent, combinations of compounds with different functionality are incorporated into the packaging system. It is important to mention that the selection of active agents depends
mainly on the characteristics of the product. In this way, antioxidants are used in
Y. N. Alonso et al.