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Green-Seeds.com
Fruits
& Others
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Postharvest Cooling and Handling of Cactus (Prickly) Pear
Adel A. Kader Department of Pomology, University of California, Davis,
CA 95616
Maturity Indices
Fruit size and fullness, external color changes from green to yellow or
red, abscission of the glochids (tufts of very small spines), fruit firmness,
and flattening of the floral cavity. Cactus pears should be picked when
fully-ripe to assure good flavor quality.
Quality Indices
Uniformity and intensity of the characteristic color of each cultivar
(pale-green, yellow, orange, red, or purple), size, freedom from defects
and decay. There are large differences among cultivars in total soluble
solids (12-17%), titratable acidity (0.03-0.12%), pH (6.0-6.6), and ascorbic
acid contents (20-40 mg/100g fresh weight).
Optimum Temperature
6-8°C (43-46°F); storage potential is 2-5 weeks; depending on
cultivar, ripeness stage, and harvest season.
Optimum Relative Humidity
90 to 95% packaging in perforated plastic bags or box liner is effective
in reducing water loss under lower relative humidities.
Rates of Respiration
Cactus pear is a non-climacteric fruit with relatively low respiration
rate [15-20 ml CO2/kg·h at 0°C (68°F)]. To calculate heat
production multiply ml CO2/kg·h by 440 to get Btu/ton/day or by
122 to get cal/metric ton/day.
Rates of Ethylene
Production Less than 0.3 µl/kg·h at 20°C (68°F)
Responses to Ethylene
No published information but since cactus pears are picked fully-ripe
it is likely that they are not affected by postharvest exposure to ethylene.
Responses to Controlled Atmospheres(CA)
Limited research (in Italy) indicates that storage of cactus pears at
5°C (41°F)in 2% O2 + 2-5% CO2 delays ripening and extends storage-life
(based on appearance quality) to 4-8 weeks (compared to 2-4 weeks in air
storage).
Physiological Disorders
Chilling Injury: Exposure to temperatures below 5°C (41°F) for
longer than a few days causes chilling injury, as indicated by pitting
and dark-brown spots on the peel surface and increased susceptibility
to decay. Conditioning at 38°C (101°F) for 24 hours reduces incidence
and severity of chilling injury during subsequent handling at temperatures
below 5°C (41°F).
Pathological Disorders
Physical damage to the peel and stem-end during harvesting and handling
and/or chilling injury predispose cactus pears to attack by decay-causing
pathogens, including Penicillium spp., Alternaria spp., and Dothiorella
ribis. Curing [1-2 days at 20°C (68°F)] to encourage wound healing
and/or prestorage dipping in water at 55°C (129°F) for 5 minutes
can reduce decay incidence and severity during subsequent storage.
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Green - Seeds Co., Ltd.
81/10B Ho Van Hue Street, Phu Nhuan District, Ward 9, Ho Chi Minh City, Vietnam
Tel: +84 (8) 847 6901 - Fax: +84 (8) 844 1392 - Email: info@green-seeds.com
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