Postharvest Enhancement of Phenolic Phytochemicals in Apples for Preservation and Health Benefits - Postharvest Biology and Technology of Fruits, Vegetables, and Flowers - page 352

conditions to extend shelf life, improve safety or maintain sensory properties of food”
(Quintavalla and Vicini, 2002), and includes MAP (modified atmosphere packaging), an-
tioxidant packaging, and other functional components. There is new interest in antioxidant
films and in finding new potential antioxidant components. If more effective antioxidants
can be successfully applied in films, another useful barrier can be created against oxidation,
decomposition, and deterioration of foods. We propose the development of a new generation
of active films and coatings. Current active packaging slows deterioration changes in food.
The next generation of coatings will modify the biochemistry of raw foods to increase the
concentration of positive health factors such as phenolic antioxidants.

16.9 Application of antioxidants films and commercialization

Due to the complexity of food, many factors influence the type of film and coating material
to be used, including intrinsic food properties (pH, water activity, and composition) and
extrinsic factors (temperature and relative humidity in processing and storage conditions)
(Min et al., 2005). These factors may interact during processing or storage to give unexpected
results. Due to the unpredictability of these interactions, commercialization of potential
antioxidants in package materials and film forming is difficult. Packaging films incorporated
with antioxidants can extend the shelf life of various foods including fruit and vegetables.
For example, antioxidants can prevent or delay lipid peroxidation by binding iron ions and
by stabilizing heme compounds, thereby stabilizing color, flavor, and sensory properties.
For example, low-density polyethylene films with 0.1% tert-butyl-hydroxyanisole added
resulted in higher “a” (redness) values in fresh beef compared to beef in control, tert-butyl-
hydroxyanisole, rosemary extract, and α -tocopherol films by days 8 and 9 (Moore et al.,

2003; Min et al., 2005).

16.10 Incorporation methods and migration of antioxidants

According to Quintavalla and Vicini (Quintavalla and Vicini, 2002), there are two common
methods to incorporate components during film formation. The component can be placed
into the film by addition to the extruder when the film is produced. The disadvantage of
this method is poor cost-effectiveness since active components not exposed to the surface
of the film are generally rendered inactive. An alternative to extrusion is to apply the active
component in a controlled manner where the material is needed and not lost; for example,
it can be incorporated into the food-contact layer of a multilayer packaging material. Also,
active films can be classified in two types by migration methods: (1) those that contain an
active agent that migrates to the surface of the food and (2) those that are effective without
migration (Suppakul et al., 2003). While much of the research has been with antimicro-
bials, the antioxidants can be treated in the same manner. Active substances (antimicrobial
or antioxidant components) can be added by different methods such as spray/coating be-
fore and after packaging, incorporation of active substances, and chemical immobilization
after which substance can migrate to foods at different rates (Fig. 16.7; Min et al., 2005).
Chemical immobilization can be performed by a nonfood agent. For successful application
of antioxidant films with foods, various factors are to be considered such as water activity,
pH, temperature, chemical interaction with film matrix, physical properties of packaging
material, cost, and FDA approval.