Bushberries

MATURITY & QUALITY

Maturity Indices

Generally based on berry surface color. Soluble solids and titratable acidity may also be considered. All berries should be harvested near ripe as eating quality does not improve after harvest.

Quality Indices

• Appearance (color, size, shape, freedom from defects)
• firmness
• flavor (soluble solids, titratable acidity and flavor volatiles)
• nutritional value (Vitamins A & C)

TEMPERATURE & CONTROLLED ATMOSPHERE (CA)

Optimum Temperature

0±0.5°C (32±1°F) for blackberry and raspberry (2-5 days); and blueberry (1-2 weeks) 3±1°C (37±2°F) for cranberry (2-4 months).

Optimum Relative Humidity

90-95%

Rates of Respiration Production

To calculate heat production multiply ml CO₂/kg·h by 440 to get Btu/ton/day or by 122 to get kcal/metric ton/day.

Rates of Ethylene Production

0.1-1.0 µl / kg·hr at 5°C (41°F)

Responses to Ethylene

Blackberries and raspberries do not respond to ethylene by stimulation of ripening processes. Blueberries are climacteric fruit and respond to ethylene; but should be harvested near to full ripe as flavor does not improve after harvest. Removal of ethylene from storage air may reduce disease development.

Responses to Controlled Atmospheres (CA)

Modified atmosphere packaging for shipment with 15 to 20% carbon dioxide and 5 to 10% oxygen reduces the growth of Botrytis cinerea (Grey Mold Rot) and other decay causing organisms, and reduces the respiration and softening rates of blueberries, raspberries and blackberries thereby extending postharvest life. Whole pallet covers and consumer packages for containment of the modified atmosphere are commonly used. Prompt cooling should be done before atmosphere modification.