Rambutan

MATURITY & QUALITY

Maturity Indices

Rambutan fruits are borne in clusters; each fruit has seeds surrounded by an aril (edible portion) which is covered by the pericarp and its hairs or soft spines or spinterns (1-1.5 cm long). Attainment of red color is the main harvest index. A minimum soluble solids content of 16% may also be used; cultivars vary in their maximum soluble solids content from 17 to 21%.

Quality Indices

• Size, uniform reddish, color, freedom from defects and decay.
• Sweetness is related to sugar content (average is 10% sucrose + 3% fructose + 3% glucose = 16% total).
• Low acidity (average is 0.36%, mainly citric acid)
• Good source of Vitamin C (average is 70 mg/100g edible portion).
• Browning, which detracts from visual quality, is directly associated with water loss and physical damage.

TEMPERATURE & CONTROLLED ATMOSPHERE (CA)

Optimum Temperature

10-12°C (50-54°F) depending on cultivar
(cultivars vary in their chilling sensitivity)
Storage potential = 12-14 days.

Optimum Relative Humidity

90-95%; maintenance of high RH is essential to minimizing water loss and preventing skin darkening (browning).

Rates of Respiration

20-60 ml CO₂/kg·hr at 25°C (77°F); non-climacteric respiratory pattern.
To 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

0.1 to 0.7 µl/kg·hr at 25°C (77°F).

Responses to Ethylene

Rambutans are picked ripe and do not benefit from ethylene treatment or ethylene scrubbing during their postharvest handling.

Responses to Controlled Atmospheres (CA)

An atmosphere of 3-5% O₂ and 7-12% CO₂ reduces respiration rate and retards red color loss and other symptoms of senescence. Postharvest-life potential in CA is 4 weeks (vs. 2 weeks in air).