Agriculture Reference
In-Depth Information
under air (Pelayo et al., 2003). Keeping wild strawberry fruits (
Fragaria vesca
L.) at under
10 kPa of CO
2
and 11 kPa O
2
efficiently prolonged the shelf life by maintaining the quality
parameters within acceptable values, without significantly modifying consumer acceptance
(Almenar et al., 2006). The flavor and external appearance of grapefruit stored for 21 days
at 14
◦
C under ultra-low oxygen and 14 additional days in air at 23
◦
C was rated acceptable,
yet inferior to grapefruit stored similarly in air (Shellie, 2002). On the other hand, freshly
harvested “Kyoho” table grapes (
Vitis vinifera
Vitis labrusca
) were stored in controlled
atmosphere, either in high oxygen concentration (80 kPa O
2
)or40kPaO
2
+
×
30 kPa CO
2
.
Storage in 80 kPa O
2
or 40 kPa O
2
+
30 kPa CO
2
improved flavors over control fruits
stored in air. Treatment in 80 kPa O
2
resulted in significantly high sensory scores than those
treated with 40 kPa O
2
+
30 kPa CO
2
, but did not significantly affect the aroma (Deng
et al., 2005).
The effect of CA on sensory quality of several vegetables was also tested. Mature green,
breaker, and pink tomatoes (
Lycopersicon esculentum
Mill.) were treated in air or in CA at
0.5 kPa O
2
and 80 kPa CO
2
. Aroma and taste were not enhanced by any treatment/ripeness
combinations, although high CO
2
marginally increased the sweetness and blandness of the
fruit (Ratanachinakorn et al., 1997). Sensory assessment of green asparagus (
Asparagus
officinali
) indicated that spears held in CA for 6 days had similar flavor and acceptability
to spears held in air for 1 day. Spear quality was more strongly influenced by CA than
by feeding solutions (Renquist et al., 2005). Gomez and Artes (2004) reported that CA
improved sensory quality of green celery stalks. Neither off-odors nor off-flavors were
detected in stalks from any treatment.
14.4.2 Modified atmosphere packaging and coatings
Modified atmosphere packaging (MAP) involves the modification of the head space gas
in a package in order to prolong the shelf life of the product it contains. The success
of MAP depends on the packer's ability to correctly prepare the product and to con-
trol the concentrations of head space gas within the desired limits. Edible coatings and
films can provide an alternative for extending the postharvest life of fresh fruits and vege-
tables.
Bagging of peach (
Prunus persica
) on tree increased fruit flavor through an increase
in aroma volatile content (Jia et al., 2005). The postharvest quality of papaya (
Carica
papaya
L.) was enhanced significantly by combining MAP (3-5 kPa O
2
; 6-9 kPa CO
2
)
with methyl jasmonate treatments. The modified atmosphere created inside the package
did not induce any off-flavor development during storage at 10
◦
C (Gonzalez-Aguilar et
al., 2003). Harvested fresh mature green papaya (
C. papaya
L.) fruits were individually
shrink-wrapped with Cryovac D-955
R
film. The shrink-wrapped papaya fruits could be
stored for 10 days at ambient temperature, after which they ripened normally in 5 days
with firm texture and good flavor after unwrapping, whereas the nonwrapped fruits ripened
within 7 days beyond which they became unmarketable (Singh and Rao, 2005).
Strawberries (
F. ananassa
) are highly perishable and are characterized by a short shelf
life. Wheat gluten-based coatings and films maintained the visual quality of refrigerated
strawberries during storage, and the taste was acceptable to consumers. However, the ap-
pearance and taste of coated fruit were unacceptable (Tanada-Palmu and Grosso, 2005).
Chitosan has been found to be an ideal preservative coating material for fresh strawberries
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