Apricot

MATURITY & QUALITY

Maturity Indices

In California, harvest date is determined by skin ground color changes from green to yellow. The exact yellowish-green color depends on the cultivar. Apricots should be picked when still firm because of their high bruising susceptibility when soft. Most apricot cultivars soften very fast making them very susceptible to bruising and subsequent decay.

Quality Indices

• Fruit size, shape, and freedom from defects and decay.
• High consumer acceptance is attained for fruit with high (>10%) soluble solids content (SSC) and moderate acidity (0.7-1.0%).
• Apricots with 2-3 pounds-force flesh firmness are considered “ready to eat”.
• Apricot cultivars have a rapid rate of fruit softening (3 pounds-force per day at 20°C (68°F).
  

TEMPERATURE & CONTROLLED ATMOSPHERE (CA)

Optimum Temperature

-0.5 to 0°C (31-32°F) is recommended. Susceptibility of cultivars to freezing injury depends on SSC, which may vary from 10-14%. Highest freezing point = –1.0°C (30.5°F).

Optimum Relative Humidity

90 to 95%

Rates of Respiration

*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

Ethylene production rates increase with ripening and storage temperature [<0.1 µl/kg · hr at 0°C (32°F) to 4-6 µl/kg · hr at 20°C (68°F) for firm-ripe apricots and higher for soft-ripe apricots].

Responses to Ethylene

Exposure to ethylene hastens ripening (as indicated by softening and color changes from green to yellow). Also, ethylene may encourage growth of decay-causing fungi.

Responses to Controlled Atmosphere (CA)

The major benefits of CA during storage/shipment are to retain fruit firmness and ground color. CA conditions of 2-3% O₂ + 2-3% CO₂ are suggested for moderate benefits; extent of benefits depends on cultivar. Exposure to 2 may result in development of off-flavors and > 5% CO₂ can cause flesh browning and loss of flavor.