MATURITY & QUALITY
Maturity Indices
Fruit color changes from green to yellow which is accompanied by an increase in soluble solids including sugars (sweetness). Carambolas should be picked when fully yellow to assure good eating quality. However, color break (1/2 to 3/4 of fruit is yellow) is used as the commercial maturity index because these fruits are firmer and easier to handle.
Quality Indices
- Yellow and firm fruits with no brown discoloration on the skin and the five ribs
- Crisp and juicy flesh
- Cultivars vary in their sweetness (glucose, fructose and sucrose) and acidity (oxalic and malic acids); sweet (pH = 3.8-4.1) cultivars include ‘Arkin’ and tart (pH = 2.2-2.6) cultivars include ‘Golden Star’
- Freedom from bruises, insect damage, bird damage, windscar, and decay
- Carambola fruits are good sources of vitamins A and C
TEMPERATURE & CONTROLLED ATMOSPHERE (CA)
Optimum Temperature
5 – 10 °C (41-50°F), depending on cultivar and production area
Lower temperature may induce chilling injury depending on cultivar, ripeness stage, and temperature and duration of storage.
Optimum Relative Humidity
90-95%
Lower humidity results in more severe symptoms of rib browning
Rates of Respiration
| Temperature | 5°C (41°F) | 10°C (50°F) | 15°C (59°F) | 20°C (68°F) |
| ml CO2/kg·hr1 | 5-10 | 8-15 | 12-18 | 20-40 |
1To calculate heat production multiply ml CO2/kg·hr by 440 to get Btu/ton/day or by 122 to get kcal/metric ton/day.
Rates of Ethylene Production
Less than 1.0 µl /kg·hr at 20°C (68°F)
Carambola is a nonclimacteric fruit
Responses to Ethylene
Green color of carambolas continues to disappear during storage at 15°C (59°F) or 20°C (68°F) and some improvement in flavor due to loss of acidity may be noted. These changes can be slightly accelerated with exposure to ethylene (100 ppm for 24 hours), but such treatment may increase decay incidence and severity.
Responses to Controlled Atmospheres (CA)
Florida carambolas can be kept in air at 5°C (41°F) for 4 to 6 weeks provided that water loss is minimized (by high relative humidity and/or packaging film barriers).There are no published data on their response to atmospheric modification.
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