Agriculture Reference
In-Depth Information
than those in the paper carton with ethylene vinyl alcohol
(EVOH) layer (Beltran-Gonzalez et al., 2009) and clear
PET bottles (Beltran-Gonzalez et al., 2008). Storage tem-
perature plays a significant effect on quality changes in both
studies.
Interactions between products and polymeric materials
can be one of the most important factors contributing to
quality changes of the aseptic fruit juices during storage
due to flavor loss, known as “flavor scalping.” Many stud-
ies were conducted to determine the sorption of d-limonene,
which is a key flavor compounds in orange juices, in vari-
ous polymeric films (Kwapong and Hotchkiss, 1987; Imai
et al., 1990; Sheung et al., 2004; Auras et al., 2006). Primary
factors affecting flavor sorption include polymer morphol-
ogy and polarity. Sorption values are higher in polyolefin
such as LDPE and PP than polar polymers such as PET,
PA, and EVOH (Imai et al., 1990; Nielsen et al., 1992).
Poly(lactide) (PLA) to d-limonene was reported to have
low sorption and permeability coefficients as compared to
PET, PP, and LDPE (Auras et al., 2006) and HDPE and
PS (Haugaard et al., 2002). The low permeability coeffi-
cients of PLA to d-limonene indicate that PLA is a high
barrier to d-limonene, suggesting a potential of PLA as
a good aroma barrier for food packaging (Auras et al.,
2006). Addition of the polar layer such as PET and PVdC
to the laminated packaging materials reduced absorption
of d-limonene (Sheung et al., 2004). Product/package
interactions are the important factor in selecting poly-
meric
Oxygen scavengers (e.g., nylon MXD6 and benzoacry-
lates) are incorporated into the packaging structures. When
combined with the high oxygen barrier closures containing
oxygen scavengers, the plastic bottles offer ideally imper-
meable to oxygen (Brody, 2005). By means of scavenging
systems, packaging can actively absorb compounds that
cause or relate to quality changes and deterioration of pack-
aged food products. As oxygen is the main cause of food
deterioration and spoilage, limited oxygen in the package
environment generally results in food products with ex-
tended shelf life. While oxygen absorbing sachet is not
commonly used and projected decline in use in the USA
(Brody, 2005), it is popular in Asia and is applied with a
wide variety of processed products such as dried and dehy-
drated fruits.
Release of carbon dioxide was among the earliest meth-
ods used to extend the shelf life of processed products such
as coffee through the same principle of MAP. Carbon diox-
ide has shown inhibitory effects on microbial spoilage of
some dried and dehydrated fruit products as in MAP un-
der high carbon dioxide levels. Active releasing systems
have been widely studied in the past decade. Various re-
leasing compounds have shown a wide range of effects on
many processed fruit products. Most studies have focused
on the antimicrobial and antioxidant effects of releasing
compounds for extending the shelf life of food products;
most of these compounds are major constituents in fruits.
Releasing of flavor and aroma compounds by packaging
materials/systems is gaining interest, as flavor and aroma
are among the most significant factors in food quality and
consumer perception which affect the shelf life of food
products. Recently, controlled release packaging (CRP) is
gaining interest for research and development as one of the
most innovative active packaging technology. The principle
of CRP is a release of active compounds from packaging
materials at different controlled rates (LaCoste et al., 2005).
materials
with
optimized
thickness
for
aseptic
fruit products.
MAP of processed fruits
MAP has been widely studied and reviewed, but mostly
applied for fresh fruits, fresh-cut fruits, and fresh meats.
MAP has not commonly been applied for processed fruits,
but mostly for processed meats, bakery products, and some
prepared meals (Brody, 2005). Optimum gas compositions
for MAP of processed fruits vary among products. In gen-
eral, dried, dehydrated, moisture-sensitive fruit products
are packed in high carbon dioxide or nitrogen levels (i.e.,
60-70% CO
2
+
PACKAGING FOR INNOVATIVELY PROCESSED
TROPICAL AND SUBTROPICAL FRUITS
With time, conventional food processing technologies, es-
pecially thermal processing, are gradually replaced by or
combined with newer processing technologies known as
novel food processing technologies such as high-pressure
processing (HPP), pulse-electric field (PEF) heating, ohmic
heating, radio frequency/microwave heating, and so on.
Packaging is a key factor to the feasibility of novel pro-
cessing since it plays a role in preserving the maximum
of the intrinsic qualities of non-thermally processed food.
Among many packaging materials, plastics have been
30-40% N
2
or 100% N
2
). Carbon dioxide
is shown to inhibit the growth of many spoilage microbes,
while nitrogen is inert and commonly used as filler. Vacuum
packaging is an evacuation of air from a package before
sealing it. Under conditions of limited oxygen, shelf life of
the products is extended as described above.
Active packaging of processed fruits
The most common form of active packaging of processed
fruits is high-barrier plastic bottles for fruit beverages.
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