Agriculture Reference
In-Depth Information
The applications of edible fi lms to fresh fruits and vegetables have received
increasing interest because these fi lms can serve as carriers for various anti-
microbial compounds that can reduce the risk of pathogen growth
.
Preservatives,
acidulants, antioxidants, and antibiotic compounds can be added to edible fi lms to
reduce surface microbial populations on foods and enhance oxygen-barrier properties.
Edible fi lms can also enhance food nutritional value and improve the appearance of
foods. A greater emphasis on safety features associated with the addition of antimi-
crobial agents is the next area for development in edible fi lms technology (Cha and
Chinnan 2004 ).
Fruit and Vegetable-Based Edible Films
McHugh and others (1996) developed the fi rst edible fi lms made from fruit purées and
characterized their water vapor and oxygen permeability properties. Fruit-based edible
fi lms were excellent oxygen barriers, particularly at low to moderate relative humidi-
ties. McHugh and Senesi (2000) coated apple pieces by dipping into solutions and then
drying or wrapping in preformed apple-based edible fi lms. Increasing the lipid concen-
tration of the fi lms signifi cantly improved its moisture barrier properties. Water vapor
permeability values were reduced from 325 to 69 g - mm/kPa - d - m
2
through the addition
of lipids. Apple-based wraps signifi cantly reduced moisture loss and browning in fresh-
cut apples, retaining color for 12 days at 5 °C. Wraps were signifi cantly more effective
than coatings of the same composition (McHugh and others 1997).
In addition to providing antimicrobial properties, fruit- and vegetable-based edible
fi lms can benefi t consumers in other ways. For example, although the USDA Food
Guide Pyramid recommends that mature adults consume 2-4 servings of fruit per day,
less than half of Americans meet these dietary recommendations. Because consumers
demand convenience and variety, there is a need to provide access to fruit products
in new, innovative forms. Incorporation of fruit purées into edible barrier fi lms can
help meet these needs. Fruit fi lms, due to their low moisture levels, are concentrated
sources of natural nutrients and can impart appealing colors and fl avors.
Apple and tomato purées have been used to prepare model edible fi lms in recent
studies to incorporate antimicrobial plant essential oils (Rojas- Gra ü and others 2006 ,
2007a; Olsen and others 2008). Undoubtedly, the results can be extrapolated to other
fruit - and vegetable - based fi lms. Based on the interest in the use of fruit and vegetable
fi lms, a commercial partner, Origami Foods, has begun to commercialize fruit- and
vegetable - based edible fi lms.
A potential application of fruit- and vegetable-based edible fi lms is the controlled
release of volatile active antimicrobial compounds from the natural essential oils of
plants. Because plant essential oils and some fruit and vegetable products are com-
monly found in combination food products such as pizza, which contains tomato,
basil, and oregano, it is anticipated that the fl avors of plant essential oils and other
antimicrobial phytochemicals added to the fruit and vegetable fi lms will be readily
acceptable to consumers (Rojas-Graü and others 2007b). Edible fi lms can then be
incorporated into conventional packaging systems (Koide and Shi 2007) for fresh and
fresh-cut fruits and vegetables with a dual purpose as edible and antimicrobial
components.
