Olive

MATURITY & QUALITY

Maturity Indices 

Green olives. Size and color (even, pale green with a minimum of whitish spots (lenticels) through a straw color. An olive is considered mature if it exudes a characteristic white juice when squeezed.

Black olives. Color, removal force; fruits reach this stage about 3-4 months after the green stage.

Quality Indices 

Green olives. Color; freedom from mechanical damage, shrivelling, surface blemishes, scale and other insect injury, and decay. These olives are processed according to the California black-ripe style or Spanish green style canned olives.

Black olives. Color, freedom from defects, oil content (12 to 25% depending on cultivar). These are processed (Greek or Italian style) or used for oil extraction.

TEMPERATURE & CONTROLLED ATMOSPHERE (CA)

Optimum Temperature

5 – 7.5°C (41-45.5°F); temperatures below 5°C (41°F) cause chilling injury of fresh olives.

Optimum Relative Humidity

90-95%

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

Less than 0.1 (green olives) or 0.5 (black olives) µl ethylene/kg·hr at 20°C (68°F).

Responses to Ethylene

Olives produce very little ethylene but are moderately sensitive to ethylene action above 1 ppm (loss of green color and flesh firmness).

Responses to Controlled Atmospheres (CA)

Optimum CA 2 – 3% O₂+ 0 – 1% CO₂; delays senescence and softening for up to 12 weeks at 5°C (41°F) or 9 weeks at 7.5°C (45.5°F).

O₂ below 2% can cause off-flavors.

CO₂ greater than 5% may increase the severity of chilling injury if olives are kept below 7.5°C (45.5°F).

Note: The above information is for fresh green olives; fresh black olives should be processed as soon after harvest as possible.