Agriculture Reference
In-Depth Information
Moderate CO
2
(5% to 10%) may be useful to reduce
discoloration and other visual defects of cut cladodes.
An extension of shelf life and maintenance of chemical
and sensory attributes of prickly pear fruit (
Opuntia ficus-
indica
cv. Gialla) for 8 days was achieved by placing in
polystyrene trays sealed with polyolefinic films and stored
at 4°C (Piga
et al
. 2000, 2003). Fruit texture was also
reported to be maintained in ethylene-vinyl acetate (EVA)
for 7 days at 5°C (Saenz
et al
. 2001). MAP at 4-8°C for up
to 7 days was reported to reduce microbial spoilage by
mesophilic bacteria (staphylococcus spp., Enterobacter
spp., Leuconostoc mesenteroides), as well as yeasts (Corbo
et al
. 2004).
(a)
2.5
2.0
1.5
1.0
0.5
0
(b)
2.5
2.0
1.5
1.0
0.5
0
(c)
6.0
SUMMARY
Prickly pear fruit are produced and consumed in several
countries, and cladodes are traditionally consumed in
Mexico and some parts of the United States as vegetable,
and also exported to few other countries. Both have been
suggested to have several health benefits. They can be
readily and abundantly produced under high temperature
and little water, conditions unfavourable for the produc-
tion of many other crops, and therefore interests in their
production and consumption is increasing. Cactus plants
serve numerous purposes; such as sources for fruit and
vegetables, for medicinal and cosmetic purposes, as
forage, for building materials and as a source for natural
colours. However, many of these uses are still very
restricted to a very few countries, and in light of global
desertification and declining water sources,
Opuntia
spp.
is gaining importance as an effective source of food
including as a vegetable. The fruit is relatively perisha-
ble an can be kept for 2 to 5 weeks at 5°C to 8°C with
90-95% RH, and several factors can limit storage life
such as decay, dehydration and CI. Cladodes are more
perishable than fruit and can be maintained for only a
few days at 5°C with 95-99% RH, and major factors
limit their storage life including CI, decay and dehydra-
tion. Modified and controlled atmospheres can delay rip-
ening and senescence and extend storage life of both
fruit and cladodes.
4.0
2.0
0
0
10
20
Days at 5
30
40
°
C
Figure 13.10
Changes in total microbial count (AeM,
AnM, molds and yeast) in passive and semi-active
MA-packaged prickly pear cactus stems stored at
5°C for up to 35 days. Non packaged (●), passive
MAP (❍), 20% CO
2
(▼), 40% CO
2
(
∇
) and 80% CO
2
(■). Vertical bars represent standard error of the
mean (Guevara
et al
. 2003, with permission).
great variety of situations involving different commodities.
This approach should facilitate package designing for fresh
produce, and therefore maximizing the benefits of MAP
for horticultural products. Another major conclusion of
this study, however, is that the relative humidity around the
packages (e.g. in the display cabinet of retail stores) can
have a major impact on the respiration and gas exchange of
MAP packed products. This could well be the missing link
in understanding the sometimes erroneous and incompre-
hensible results obtained with MAP packages in practice.
FRESH-CUT
In Mexico cladodes are commonly processed and packed
as fresh-cut, however, reducing brown discolouration at cut
surfaces and preventing fluid (mucilage) loss are the main
problems in handling diced cactus stems. Cut cladodes
cannot be washed before marketing, because it will cause
mucilage to exude and enhance discoloration of cut sur-
faces. Shelf-life of diced cladodes was 1 day at 20
REFERENCES
Alvarado, L.S. (1978) Physiology and biochemistry of devel-
opment of the tuna fruit (Opuntia amyclaea T). M. Sc.
Thesis, Natl. School of Agric., Chapingo, Mexico (in
Spanish).
Amin, E.S., Awad, O.M. & El-Sayed, M.M. (1970) The muci-
lage of
Opuntia ficus-indica
Mill.
Carbohydrate Research
,
15
, 159-161.
°
C and 6
days at 5
°
C (Rodríguez-Felix & Soto-Valdez 1992).
