Cherry

MATURITY & QUALITY

Maturity Indices

Skin color and soluble solids content (SSC) are the main criteria used to judge fruit maturity. Minimum maturity in California requires that the entire cherry surface have a minimum of light red color and/or 14 to 16% SSC, depending on the variety. The red mahogany stage is recommended for harvest of Brooks, Garnet, Ruby, Tulare and King varieties.

Quality Indices

• Taste is related to SSC, titratable acidity (TA) and the ratio of SSC/TA.
• Freedom from cracks, bird pecks, shriveling, decay or misshappen fruit (doubles, spurs)
• Green fleshy stems are often associated with freshness and quality

TEMPERATURE & CONTROLLED ATMOSPHERE (CA)

Optimum Temperature

-0.5 ± 0.5°C (31 ± 1°F)

Optimum Relative Humidity

90-95%; high humidity is particularly important to maintain green stem color.

Rates of Respiration Production

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

< 1 µl/kg·hr at 20°C (68°F)

Responses to Ethylene

Cherry response to ethylene is minimal. Ethylene does not accelerate cherry ripening.

Responses to Controlled Atmospheres (CA)

CA reduces respiration rate and thereby increases postharvest life. Elevated CO₂ suppresses decay development. Modified atmosphere packaging within boxes has been very successful. Successful atmospheres are generally within the following ranges:

3 to 10% O₂
10 to 15% CO₂
< 1% O₂ can result in skin pitting and off-flavors
> 30% CO₂ can result in brown skin discoloration and off-flavors.

Flavor volatiles may be reduced following several weeks of CA storage resulting in fruit of good visual quality but poor sensory quality.