Institute of Polymer Chemistry and Technology, C.N.R., Italy
Abstract:
In order to defend against damage from oxidation, organisms have developed complex antioxidant
activity to scavenge reactive oxygen species (ROS) thereby protecting key biological sites from
oxidative damage. These antioxidants are either produced by the body or derived from diets. The
desire for new sources of safe and inexpensive antioxidants of natural origin has resulted in
considerable interest in herbs and spices as sources of natural antioxidants. Several studies have
found many commonly used herbs and spices to be excellent sources of natural antioxidants which
contain a diverse array of compounds such as phenolic acids, flavonoids, tannins, vitamins and
terpenoids that account for their antioxidant properties. The area of polymer degradation and stabilization is still an area
of appreciable industrial interest supported by corresponding research activities in several universities and industrial
laboratories. In this contest, the interest for natural antioxidant is also motivated by the necessity to increase the amount
of natural substances in the compounding of polymers. In the first part of this lecture, tocopherol and by-products
containing polyphenols and tannins deriving from grape processing for wine production, as well as carotenoidcontaining
waste from processing of tomatoes, were tested as potential antioxidants for polypropylene, to partially
substitute synthetic, oil-based stabilizers. In the second part, active food packaging will be discussed as an innovative
tool to meet the continuous changes in current consumer demands and market trends. Active food packaging extends
shelf life and improves safety of the food by scavenging of oxygen, moisture or ethylene, and by promoting emission of
ethanol, flavours, and antimicrobial agents. Antimicrobial packaging is attracting increasing attention from the food and packaging industry, since the use of preservative packaging films offers several advantages compared with the direct
addition of preservatives into food products. The incorporation of antimicrobial agents into polymeric films allows
industry to combine the preservative functions of antimicrobials with the protective functions of the pre-existing
packaging concepts. Some results will be presented on the development of antimicrobial films of low-density
polyethylene (LDPE) containing carvacrol. As reported in literature, one drawback of PE liners in barrier packages for
e.g., aseptically processed juices, is the loss of flavour/aroma due to the scalping effect of the polymer membrane.
Nanoparticles were used to improve the barrier properties of packaging films and to protect the volatile and heatsensitive
carvacrol from degradation. In this frame, the nanoclay filler is believed to positively interact with carvacrol
dispersed into clay galleries, thus preserving the antimicrobial activity of the doped film.
