Agriculture Reference
In-Depth Information
fruits from different stages along the line. Lowest amounts
of rot were found in fruit sampled immediately prior to the
packing line and highest amounts at the end of the line,
after the lychee had been destalked by hand, sorted and
hydro-cooled. The authors suggested further work to deter-
mine if handling practices could be improved to reduce
accumulation of rots during commercial processing.
An alternative to fungicides is a hot-water spray and dip,
for example at 45°C for 30 minutes in Florida (Kader
2000b) or 49°C for 20 minutes in Hawaii (Follett et al .
1998). Using cv. Kwai May Pink, Olesen et al . (2001)
found that control fruit reached 50% rot coverage 15%
more quickly than the best 52°C dipped fruit. This is
approximately half the effect of a 52°C benomyl dip on
rot  development on the same cultivar, a useful effect given
that benomyl is no longer registered.
A patented heat treatment method has been used in
Israel, involving five weeks of refrigeration followed by
three days at 28°C.
packing fruit wet because the water evaporates quickly
from the treated fruit. However, there are concerns about
packing fruit when it is warm (Menzel 2002). These
technologies should be integrated to provide a range of
strategies to improve lychee post-harvest handling.
Other suggestions in Australia highlighted the need for a
checklist of best practice for post-harvest handling along
the supply chain and case studies to identify the compo-
nents of successful systems, guidelines for fruit sampling
and  systems' monitoring, market access protocols and
consumer research to identify key attitudes to lychees
so  that research and development would better match
consumer expectations (Chay-Prove 2003).
Use of modified atmospheres containing oxygen and
carbon dioxide have been assessed but the use of other
gases such as nitrous oxide (Qadir & Hashinaga 2001) and
low oxygen (Techavuthiporn et al . 2003a, 2003b) deserves
examination.
REFERENCES
Agar, I.T., Massantini, R., Hess-Pierce, B. & Kader, A.A.
(1999) Postharvest CO 2 and ethylene production and quality
maintenance of fresh-cut kiwifruit slices. Journal of Food
Science , 64 , 433-440.
Akamine, E.K. & Goo, T. (1973) Respiration and ethylene
production during ontogeny of fruits. Journal of the
American Society for Horticultural Science , 93 , 381-383.
Ali, Z.M. & Lazan, H. (1997) Guava. In: Postharvest
Physiology and Storage of Tropical and Subtropical Fruits
(ed. S. Mitra). CAB International, Wallingford, UK.
Anon. (1996) Lychee. California Rare Fruit Growers, Fullerton
CA, US. http://www.cfrg.org/pubs/ff/lychee.html.
Anon. (2000) Taiwan Agricultural Yearbook . Department of
Agriculture and Forestry, Taiwan Provincial Council, Taiwan.
APL (undated) Reefer-commodity handling table. http://
www.apl.com/reefer/html/commodity-table.html.
Arjona, H.E., Matta, F.B. & Garner, J.O. (1992) Temperature
and storage times affect quality of yellow passion fruit.
HortScience , 27 , 809-810.
Arjona, H.E., Matta, F.B. & Garner, J.O. (1994) Wrapping in
polyvinyl chloride film slows quality loss of yellow passion
fruit. HortScience , 29 , 295-296.
Bassetto, E., Jacomino, A.P., Pinheiro, A.L. & Kluge, R.A.
(2005) Delay of ripening of 'Pedro Sato' guava with
1-methylcyclopropene. Postharvest Biology and Techno-
logy , 35 , 303-308.
Batten, D.J. (1989) Maturity criteria for lychees. Food Quality
Preference , 1 , 149-155.
Bauchot, A.D., Harker, F.R. & Arnold, W.M. (2000) The use
of electrical impedance spectroscopy to assess the physical
condition of kiwifruit. Postharvest Biology & Technology ,
18 , 9-18.
Physiological disorders
Browning is the main physiological disorder in lychee
(Underhill et al . 1997). Browning of the pericarp from
water loss is manifest by the appearance of brown spots
against the normal bright red background colour. In severe
cases the spots may coalesce and cover the whole surface
of the fruit. Arils within may not be affected but the fruit
will be downgraded because of the external colour change.
Water loss may also lead to percarp splitting or cracking.
Breakdown of the arils results from prolonged storage and/
or over maturity - the effects are seen as softening, loss
of   turgor and translucency and loss of flavour. Damage
commences at the blossom end of the fruit and spreads
towards the stem end. Chill injury symptoms such as
pericarp browning and increased decay susceptibility
resulted from 12 day's storage at 1°C followed by one day
at 20°C (Kader 2000b).
Future needs
Olesen et al . (2004) pointed out that methods of improving
lychee shelf lives in commercial outlets have not been
investigated. In retail outlets fruits may be exposed on
shelving and lose their attractive appearance in less than a
day. Promising developments include coatings to reduce
water loss. Thus Zhang and Quantick (1997) used a solu-
tion of chitosan and L-glutamic acid to reduce water loss at
4°C by 20% and significantly slow browning. Packaging
that maintains high humidity but minimises the appearance
of free water on fruit surfaces is another promising area.
The use of hot-water sprays does not bring problems of
Search WWH ::




Custom Search