MATURITY & QUALITY
Maturity Indices
Based on berry surface color. US: minimum 1/2 or 3/4 berry surface showing red or pink color, depending on grade. Calif.: minimum 2/3 berry surface showing red or pink color.
Quality Indices
- Appearance (color, size, shape, freedom from defects),
- Firmness
- Flavor (soluble solids, titratable acidity and flavor volatiles)
- Nutritional value (Vitamin C)
- For acceptable flavor, a minimum of 7% soluble solids and/or a maximum of 0.8% titratable acidity are recommended.
TEMPERATURE & CONTROLLED ATMOSPHERE (CA)
Optimum Temperature
0 ± 0.5°C (32 ± 1°F)
Optimum Relative Humidity
90 to 95%
Rates of Respiration
| Temperature | 0°C (32°F) | 10°C (50°F) | 20°C (68°F) |
| ml CO2/kg·hr | 6 – 10 | 25 – 50 | 50 – 10 |
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.
Rate of Ethylene Production
< 0.1 µl/C2H4/kg·hr at 20°C (68°F)
Response to Ethylene
Strawberries do not respond to ethylene by stimulation of ripening processes (strawberries should be harvested near to full ripe). Removal of ethylene from storage air may reduce disease development.
Responses to Controlled/Modified Atmospheres
Modified atmosphere packaging for shipment with 10 to 15% carbon dioxide reduces the growth ofBotrytis cinerea (Grey Mold Rot) and reduces the respiration rate of the strawberries thereby extending postharvest life. Use of whole pallet covers for modified atmospheres is the most common method.
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